Hachyderm Blog

• Announcements
• Crypto Spam Attacks on Fediverse
• Updating Domain Blocks
• Opening Hachyderm Registrations
• Posts
• A Minute from the Moderators
• A Minute from the Moderators
• Stepping Down From Hachyderm
• A Minute from the Moderators
• A Minute from the Moderators
• Decaf Ko-Fi: Launching GitHub Sponsors et al
• Growth and Sustainability
• Leaving the Basement
• Incidents
• Security incident: Redis cache exposed to public internet
• Moderation Postmortem
• TLS Expires: media.hachyderm.io
• Fritz Timeouts
• Fritz on the fritz
• The Queues ☃️ down in Queueville
• Degraded Service: Media Caching and Queue Latency
• Global Outage: 504 Timeouts

Announcements

Crypto Spam Attacks on Fediverse

The Situation

Starting around 8 May 2023, we began to receive reports that Mastodon Social was being inundated with crypto spam.

Initially, it appeared that only Mastodon Social, and then Mastodon World, were impacted. In each case we Limited the instance and made a site-wide announcement. As the issue progressed, it became clear that more instances were being targeted for this same style of crypto spam. As a result, we have decided to change our communication strategy to utilize this blog post as a source for what’s happening and who is being impacted, rather than relying on increasingly frequent site-wide announcements.

As it stands: right now we have seen waves of spam from Mastodon Social, Mastodon World, and now TechHub Social. These waves usually mean that we receive over 100-200 reports in less than a few hours. (By contrast, we usually receive ~20 reports per week.)

What this means for Hachydermians (and Mastodon users in general)

Spam attacks seem to make use of open federation to either find accounts to misuse follow/unfollow behaviors, DMs, comments, and other invasive behaviors. In general, Limiting a server is sufficient for mitigating the impacts of these behaviors. Limiting means that Hachydermian’s posts no longer show up in the Federated feeds of impacted instances, which means that bots can no longer use the Federated feed as a vector for malicious behavior. While this is a good thing and means that these bots will no longer be able to spam Hachydermians, the Limit works both ways. This means:

• The posts for Limited instances will no longer show up on the Federated feed
• You will receive approval requests for all accounts on Limited instances
• User profiles will appear to have been “Hidden by instance moderators”

The UI messages for the latter two are a little difficult at times to determine what it means. Essentially, you will see the same message for a user to follow you from an instance that’s been Limited, and for you to view their profile page, as you would if we had only Limited that specific user.

For users on the impacted instances, these messages should not be taken as the individual user has engaged in any sort of malicious activity. In general, when we see individual-level malicious activity, we suspend federation (block) the individual user rather than Limit them. Instead, these messages are only a consequence of us needing to Limit the servers while they are doing their best to manage the spam attacks they are undergoing.

The impacted instances

We are maintaining the list of instances that we are Limiting as a result of the current crypto spam attack here. Note that this is not all instances we currently have Limited for any reason, only the ones that are experiencing this specific scenario. We will continue to announce when new instances are added to this list via our Hachyderm Hachyderm account and link back to this blog post. Instances that are no longer impacted will be un-Limited and removed from the list below. (When the list is empty, that means that all instances have been un-Limited.)

Updates

Update 25 May 2023 - we’ve been crypto spam free from Mastodon Social and Mastodon World, so we’ve gone ahead an un-Limited those instances.

Update 2 Jun 2023 - we’ve been crypto spam free from TechHub Social, so we’ve gone ahead and un-Limited that instance! That’s the last one, so this incident is resolved.

Updating Domain Blocks

Today we are unblocking x0f.org from our list of suspended instances to federate with. Hachyderm will begin federating with x0f.org immediately.

Reason for suspending

We believe the original suspension was related to early moderation actions taken earlier in 2022. The moderation actions took place before Hachyderm had a process/policy in place to communicate and provide reasoning for the suspension.

Reason for removing suspension

According to our records, we have no reports on file that constitute a suspension of this domain. The domain was brought to our attention as likely flagged by mistake. After review we have determined that there is no reason to suspend this domain.

A Note On Suspensions

It is important to us to protect Hachyderm’s community and our users. We may not always get this right, and we will often make mistakes. Thank you to our dedicated users for surfacing this (and the other 13 domains) we have removed from our suspension list. Thank you to the broader fediverse for being patient with us as we continue to iterate on our processes in this unprecedented space.

Opening Hachyderm Registrations

Yesterday I made the decision to temporarily close user registrations for the main site: hachyderm.io.

Today I am making the decision to re-open user registrations again for Hachyderm.

Reason for Closing

The primary reason for closing user registrations yesterday was related to the DDoS Security Threat that occurred the morning after our Leaving the Basement migration.

The primary vector that was leveraging Hachyderm infrastructure for perceived malicious use, was creating spam/bot accounts on our system. Out of extreme precaution, we closed signups for roughly 24 hours,

Reason for Opening

Today, Hachyderm does not have a targeted growth or capacity number in mind.

However, what we have observed is that user adoption as dropped substantially compared to November. In my opinion, I believe that we will see substantially less adoption in December than we did in November.

We will be watching closely to validate this hypothesis, and will leverage this announcement page as an official source of truth if our posture changes.

For now we have addressed some more detail on growth, registrations, and sustainability in our Growth and Sustainability blog.

Posts

A Minute from the Moderators

Hello and welcome to this month’s Moderator Minutes. Apologies for missing June, we have a blog post that we’ll post later this month as a belated post for June. The short version is we were completing that one while compiling for this one, and a lot is going on for the summer. So let’s get started!

This month we will cover: welcoming new users to Mastodon, volunteering with Hachyderm, decisions around Lemmy/kbin, and what’s going on with the Meta instance.

• New to Hachyderm and Mastodon? Welcome!
• Interested in volunteering? We’re growing our moderation team!
• What did we decide about Lemmy and kbin?
• Let’s talk about Meta.
  • How the Hachyderm instance will reach consensus about Meta and communicate about it
    • How Hachyderm handles federating with other instances
    • The current status of Meta / Threads
    • Resources for finding out more about the implications of Meta / Threads
• Hachyderm inbound and outbound communications
  • Reminder that we use Github Issues for consolidated, searchable, discussion threads
  • How we communicate site-wide

New to Hachyderm and Mastodon? Welcome!

We’re seeing an increase in Fediverse usage of users arriving from other platforms. Welcome new users! We have an explainer for How to Hachyderm in our documentation, which includes both Hachyderm specific information as well as links to common sources you’ll want to keep handy for general Mastodon or Fediverse information. Some things you’ll want to make sure to explore:

• Understanding home, local, and federated timelines
• Understanding how DMs work and their visibility (importantly: if you add someone to a DM thread they see the history, Mastodon doesn’t create a new thread).
• There’s a strong culture of content warning and alt-text (in our Accessible Posting doc) usage in the Fediverse. We do not expect anyone to be experts on these, only to iterate and improve over time.

As always, we encourage everyone to be welcoming to new transfers from other platforms. Everyone is encouraged to help new users learn the new tools and features available to them. Please keep in mind that shaming people for not knowing something goes against the ethos of the Hachyderm server, so please only enter conversations you can participate in that will foster the growth of others.

Interested in volunteering? We’re growing our moderation team!

Also, as a response to the growth we’re seeing, we’re scaling the Moderation team! If you’re interested in volunteering on the moderation team, please read on.

Hachyderm is operated by two teams: moderation and infrastructure. In an effort to protect the instance, we have implemented a SOD (separation of duties) policy, where team members can only operate in one team at a time. For those that know that they will be interested in volunteering with different teams over time, we ask that you commit to a given team for a minimum of three months (within reason). At this point in time, we are calling for volunteers to support the moderation team.

Hachyderm Moderators are expected to be able to create and maintain safe spaces. The easiest moderation decisions we make are around “banning the Nazis”. This can include literal Nazis, of course, but also extends to all forms of extremism and their “friendly federators”. It is more difficult and nuanced to handle genuine interpersonal conflict than to simply remove harmful content and sources, local or remote. In order to handle interpersonal conflict on the instance, understanding if there’s a path back into the community or not is important. In order to handle interpersonal conflict where there are one or more remote users, who have agreed to different instance rules, involves understanding which of Hachyderm’s rules are local and which are global.

As part of our current call for moderators, we included some Q&A that showcases this in the application form. It’s important to know that there are no right or wrong answers on the volunteer form and that everything we do here on the instance is covered in moderation training. What we’re looking for from you is just for you to explain to us how you’d interpret and handle the concepts and two examples we’ve provided. If you are interested in applying, please respond to our call for moderators here:

• volunteer.hachyderm.io (direct Airtable link)

If you have any questions about volunteering in general, the application form, and so on please email us at admin@hachyderm.io.

What did we decide about Lemmy and kbin?

Many of you have been waiting for the results about whether or not Hachyderm will be running a Lemmy or kbin instance. The short, at the top, answer is:

We’ve decided that a Lemmy / kbin instance will actually need to be a Nivenly project, rather than be a sub-project of Hachyderm. There will be an upcoming announcement from Nivenly about this.

In addition to information about how to apply to Nivenly as a Lemmy or kbin instance, their post will include other project announcements and exciting status updates that they know everyone has been waiting for. While the Nivenly post will have more details about what they’re looking for specifically, we can share a bit of our experience to help as well.

As one of the first two (the other being Aurae) Nivenly Projects, we can share that two things to be aware of if you’re interested in scoping out the project: Nivenly will want to ensure that any projects brought on can commit to safe spaces and there will be expectations for what that means as well as projects that are interested in improving the community space overall. This can mean that an infra team will need to have one or more members (but not all) that are interested in contributing to the project’s software where / as applicable.

For anyone with preemptive questions about this, please reach out to Nivenly using their email: info@nivenly.org.

Let’s talk about Meta.

Lastly, let’s talk about Meta and Threads. We’ve received a lot of questions and discourse about this in general over a few different comms channels, including Hachyderm itself, email, and Nivenly’s Community Discord. By the nature of these different communication pathways, this means that essentially small bubbles of conversation have appeared that don’t have a lot of visibility. We’re consolidating some of the outcomes of those discussions here, for reference. And of course, since information is ongoing that means we’ve had to make a few revisions to this blog post while we were writing it to account for newly released information.

For this section, the first thing that we’ll be covering is how we’ll come to consensus about Meta’s instance, Threads. Then we’ll go into a bit about how Hachydermians can communicate their wants and needs to us, as well as a refresher on how we send out communications.

How the Hachyderm instance will reach consensus about Meta and communicate about it

How Hachyderm handles federating with other instances

Due to the size of our instance, we openly federate by default. This is not unchanging: as we research and become aware of instances that have a negative impact on the Hachyderm community or otherwise pose a risk, we can limit or fully defederate from other instances. The most common situation for this is when we research DarkFedi instances, though this is not exclusive.

In general, there are two sets of criteria that determine whether we federate with an instance. One set for moderation, the other for infrastructure. In both cases, the instance must be federating in order to prompt defederation research.

For moderation:

• The instance must not be a source of extremist content of any format
• The instance must not be a source of illegal content of any format
• The instance must not engage in trolling or brigading of other instances or users
• The instance must not stalk or otherwise harass other instances or users
• The instance must not monetize their users’ data without their informed consent or monetize the data of other users on the Fediverse without their informed consent
• The instance must not be a “friendly federator” with an instance engaging with one or more of the above

Note: in the above criteria, we specifically do not allow instances to stalk, target, and otherwise harass either instances or individuals. Users that target other users will be defederated from, and instances that target individuals will also be defederated from. We also evaluate “friendly federation”, which analyzes the federation impact of instances actively federating with instances who are engaging in these behaviors or who are joining in outright. We take steps, which can include defederation, to protect our space from “friendly federators” just as we do the source instances.

For infrastructure:

• The instance must not be a source of spam
• The instance must not be a source of excessive traffic, such as a denial of service (DDoS)
• The instance must not be a source of any other malicious traffic or activity, including but not limited to attempts to compromise the security of the servers or the data they store.

Hachyderm teams also differentiate if an activity is limited to a specific account or accounts, rather than instance-wide. To put it another way, “is there a spam account on the instance or is the instance being overrun by spam”. In order for action to be taken against an instance in its entirety, what we surface in our research must be consistent on the instance as a whole.

As a point of clarification: although an instance must be federating for us to evaluate if we should be federating with them or not, that instance does not need to be directly engaging with Hachyderm in any way to prompt our research. The vast majority of instances that we end up researching are found proactively.

The current status of Meta / Threads

Meta formally released their Threads product this week. Currently, Threads is not federating, and cannot be defederated from until it does. Current news sources (e.g. this TechCrunch article) indicate that Meta does plan to federate with Threads and support the ActivityPub protocol, which is in use on the Fediverse, but is not doing so at this time. Less than a day into launch, and there are already reports that Twitter is threatening to sue Meta over intellectual property. (Ars Technica article here.) Basically: it launched, and there is uncertainty to the product’s future.

If and when Threads starts federating, similar to other instances on the Fediverse, Hachyderm will evaluate our federation status using the above criteria. If Threads is found to be a source of harm or risk to the Hachyderm community or Hachyderm itself, then we would defederate from them.

Several Hachydermians have indicated an interest in the above analysis and how they will know what our stance is. As a reminder, we send out announcements using one or more of the following:

• Site wide announcements
• Posts on the Hachyderm account, which are cross posted to the Nivenly Community Discord
• Blog posts

Due to high user impact of any decisions on Meta / Threads, Hachydermians should expect:

• A post from our Hachyderm account when research has begun.
• A blog post with the results of our research once it’s concluded. We will announce the blog post via a site-wide announcement and a post on the Hachyderm Hachyderm account.

Once Threads starts federating, we will do research and commit to take action, with initial announcement, within two weeks. We will follow up with a more detailed blog post within 30 days of the decision.

As a reminder, any Hachydermian can bring up questions, concerns, and requests for changes at any time. This means that regardless of the decision that is ultimately made regarding Threads, users can voice their concerns and request that decision be reversed.

Resources for finding out more about the implications of Meta / Threads

We’ve received some Q&A over a few different channels as more information started coming out over the course of June. Some of the questions asked around what would happen if the Meta instance / Threads was a source of extremism, illegal content, and so forth. The answer to all of these is the same as the above: we block and ban users and instances that engage in those activities.

There are also lots of questions about “what would happen if”. For example, what would happen if the Meta instance becomes large or starts federating? There is also a lot of speculation around concern that Meta could deploy what’s called the “embrace, extend, extinguish” strategy against ActivityPub. This basically means that Meta would adopt it, start to build it out, and then (try to) eliminate its use.

Another concern in this area is what would happen with user data. To state it clearly: Hachyderm does not and will not ever sell user data. Due to the consequences of federation, we also cannot federate with instances that sell user data.

This means that if Hachyderm does ultimately federate with Threads, if and when they start federating, it will be because they pass all the above tests and, importantly, doing so does not result in Hachydermians data being used or sold without their consent. If Hachyderm does not ultimately federate with Threads, then it will be because the instance violated one or more of our policies for federation.

As the situation is still evolving, there is a lot of speculation to be answered. The Mastodon project has a blog post that answers some of these, including what can (and cannot) be done with ActivityPub or the Mastodon software. Similarly, Nexus of Privacy is writing a deep dive into issues and concerns with Fediverse Privacy and Threat Modeling. The article is still a draft, but already contains great points to consider if you or your instance are not doing so already.

Hachyderm inbound and outbound communications

A few quick reminders for how to communicate with the Hachyderm maintainers, if you have questions or concerns or need to request changes.

Reminder that we use Github Issues for consolidated, searchable, discussion threads

We use Github Issues as a means of communication - including intentionally leaving some threads open as Community Discussions. For 1:1 conversations, please feel free to continue to use email and Hachyderm’s Hachyderm account. We’ve also created a Hachyderm Maintainers Discord user that we use for Q&A in Nivenly’s Community Discord. That said, for wider conversations please consider using the Github Issues, as other users can search for and join in on the conversation! We mention this here mostly because Github Issues is the only place we haven’t received Q&A about Meta yet.

How we communicate site-wide

We also wanted to provide a refresher for how we communicate anything that is user impacting, including decisions, outages, and so forth, as it’s relevant to both the Meta Q&A and our communications in general. The tools we use to send announcements are one or more of the following:

• Hachyderm site announcements
• Posts on Hachyderm’s Hachyderm account, which are also cross posted in the Hachyderm category of Nivenly’s Community Discord
• Blog posts and documentation

All site announcements are also cross posted as a post on Hachyderm’s Hachyderm account. We include blog posts when there is additional detail that needs to be included, for example the Crypto Spam incident from May 2023.

We take into account how high the user impact of a decision is before choosing which, or all, of the communication paths to use. So in a case where the user impact is high you can expect to see site announcements and Hachyderm posts, as well as a blog post if additional detail is needed; whereas in situations where there is low to no user impact we’d only make a Hachyderm post if one is needed.

For 1:1 communications, like Q&A and other discussions that are not announcements, we use:

• The Hachyderm Hachyderm account
• The Hachyderm Maintainers Github account
• The Hachyderm Maintainers Discord account
• Our email, which is admin@hachyderm.io

We have communications documented on our Reporting and Communications documentation page for reference.

A Minute from the Moderators

Hello Hachydermia! It’s time for, you guessed it, the monthly Moderator Minute! Recently, our founder and former admin stepped down. As sad as we are to see her go, this does provide an excellent segue into the topics that we wanted to cover in this month’s Moderator Minute!

• The big question: will Hachyderm be staying online?
• Moderation on a large instance
  • How moderators are selected
  • Moderation onboarding and continuous improvement
  • When moderators make a mistake
• Harm prevention and mitigation on large instance
  • Using research as a tool for harm prevention
  • Nurturing safe spaces by requiring active participation in moderation

The big question: will Hachyderm be staying online?

Yes!

At Hachyderm we have been scaling our Moderation and Infrastructure teams since the Twitter Migration started to land in November 2022. Everyone on both teams is a volunteer, so we intentionally oversized our teams to accommodate high fluctuations in availability. Each team has a team lead and 4 to 10 active members at any given time, meaning Hachyderm is a ~20 person org. What this means for the moderation team specifically is the topic of today’s blog post!

Moderation on a large instance

Large instances like ours are mostly powered by humans and processes. And computers, of course. But mostly humans.

And for a large instance, there needs to be quite a few humans. In our case, most of our current mods volunteered as part of our Call for Volunteers back in December 2022.

How moderators are selected

Moderators must first and foremost be aligned with the ethos of our server. That means they must agree with our stances on no racism, no white supremacy, no homophobia, no transphobia, etc. Beyond that baseline, moderators are also chosen for:

• Their lived experiences and demographics
• Their experience with community moderation

For demographics: it is important to ensure that a wide variety of lived experiences are representative on the moderation team. These collective experiences and voices allow us to discuss, build, and enforce the policies that govern our server. Ensuring that there are multiple backgrounds, including race, gender, orientation, country of origin, language, and so on helps to ensure that multiple perspectives contribute.

For prior experience: there was also an intentional mix of experience levels on the moderation team. Ensuring that there are experienced mods also means that we have the bandwidth to onboard new, less experienced moderators. Being able to lay the groundwork for mentorship and onboarding is crucial for a self-sustaining organization.

Moderation onboarding and continuous improvement

Before moderators can begin acting in their full capacity, they must:

• Agree to the Moderator Covenant
• Be trained on our policies
  • This includes the server rules, account policies, etc.
• Practice on inbound tickets
  • Practice tickets have feedback from the Head Moderator and the group

The first two points go hand-in-hand. Our server rules outline the allowed and disallowed actions on our server. Our Moderator Covenant governs how we interpret and enforce those rules.

When practicing, new moderators are expected to write their analysis of the ticket including how they understand the situation, what action(s) they would or would not take in the given scenario, as well as why they are making that recommendation. When training the first group of moderators, this portion of the process was intended to last a week, but it worked out so well that we have kept the process. This means it is common for multiple moderators to see an individual ticket and asynchronously discuss prior to taking an action. This informal, consensus-style review has led to our team being able to continue to learn from each individual’s experiences and expertise.

When moderators make a mistake

We do our best, but are human and are thus prone to mistakes. Whenever something like this happens, we:

• May follow up with the impacted user or users
• Will review the policy that led to the error

When we make mistakes, we will always do our best by the user(s) directly impacted. This means that we will take ownership for our mistakes, apologize to the impacted user(s) if doing so will not cause further harm, and also review any relevant policies to ensure it doesn’t happen again.

Harm prevention and mitigation on large instance

How we handle moderation reports is driven by the enforced stance that moderation reports are harm already done. (We mentioned this stance in our recent postmortem as well.) Essentially, this means that if someone has filed a report because harm has been done, then that harm has been done.

How we determine what to do next depends on several factors, including the scope and severity of what has been done. It also depends on the source of the harm (local vs remote).

Using research as a tool for harm prevention

To say it first: in cases of egregious harm that originates on our server, the user is suspended from our server.

Reports of abuse originating from one of our own are exceedingly rare. More commonly, the reports of egregious harm come from remote sources. The worst cases are what you’d likely expect and are easy to suspend federation with.

The Hachyderm Moderation team also does a lot of proactive research regarding the origins of abusive behavior. The goal of our research is to minimize, and perhaps one day fully prevent, these instances’ ability to interact with our instance either directly or indirectly. To achieve this, we research not only the instances that are the sources of abusive behavior and content, but also those actively federating with them. To be clear: active here means active participation. We take this research very seriously and are doing it continuously.

Nurturing safe spaces by requiring active participation in moderation

The previous section focused on how we handle the worst offenders. What about everyone else? When someone Well Actuallys or doesn’t listen, or doesn’t respond properly when a boundary has been specified? (For information about setting and maintaining boundaries, please see our Mental Health doc.)

In situations where the situation being reported is not an egregious source of harm, the Hachyderm Moderation team makes heavy use of Mastodon’s freeze feature. The way we use it is to send the user a message that details what they were reported for, including their posts as needed, and use the freeze to tell them what we need from them to restore normal activity on their account. To prevent moderation issues from going on for long periods of time, users must respond in a given time frame and then perform the required action(s) in a given time frame.

What actions we require are situationally dependent. Most commonly, we request that users delete their own posts. We do this because we want to nurture a community where individuals are aware of, and accountable for, their actions. When moderators simply delete posts, the person who made the post is not required to even give the situation a second thought.

Occasionally, we may nudge the reported user a little further. In these cases, we include some introductory information in our message and also request that the person do a brief search on the topic as a condition of reinstating the account. The request usually looks a bit like this:

We ask that you do a light search on these topics. Only 5-15 min is fine.

The goal of this request is that we can all help make our community a safer place just by taking small steps to increase our awareness of others in our shared space.

If you agree to the above by filing an appeal, we will unfreeze your account. If you have further questions, please reach out to us at admin@hachyderm.io .

– The Hachyderm Mods

The reason we ask for such a brief search is because we do not expect someone to become an expert overnight. We do expect that all of us take small steps together to learn and grow.

As a point of clarification: we only engage in the freeze and restore pattern if the reported situation does not warrant a more immediate and severe action, such as suspending the user from Hachyderm.

And that’s it for this month’s Moderator Minute! Please feel free to ask the moderation team any questions about the above, either using Hachyderm’s Hachyderm account, email, or our Community Issues. We’ll see you next month! ❤️

Stepping Down From Hachyderm

Stepping Down From Hachyderm

Recently I abruptly removed myself from the “Admin” position of Hachyderm. This has surfaced a number of threads about me, Hachyderm, and the broader Fediverse. Today I would like to offer an apology as well as provide some clarity. There are a lot of rumors going around and I want to address some of them.

Before I get into why I am stepping down as admin, I want to be crystal clear: Hachyderm allows mutual aid. Hachyderm has always allowed mutual aid.

There has never been a point in Hachyderm’s history when mutual aid was not allowed. What we have never allowed on Hachyderm, is spam. Which we see a lot of, including phishing. What we have changed positions on, is corporate and organizational fundraising.

For us to say “Hachyderm does allow mutual aid,” and “Hachyderm does not allow spam or organizational fundraising,” requires the mods to define “Mutual Aid,” “Spam,” and “Organizational fundraising.” Once defined, Hachyderm need to come up with policies for these concepts, and instruct moderators to manage them. We do not always get this right, and we rely on the community’s help to tell us when we get it wrong, and how we can be more precise in our language and our actions.

One of the things I’ve found difficult about engaging in moderation discussions on the Fediverse, is the inability to agree on the facts at hand. I’ve always been very willing to take accountability for my actions, and take feedback on how to improve and make things better for all of our users. But that’s not possible to do when we can’t even agree on the topic at hand, and when we don’t engage with each other. In this most recent incident, I’ve had to spend significantly more time re-stating that Hachyderm does support mutual aid, and less time focusing on improving our policies and communications, so that our anti-spam and anti-organizational fundraising policies don’t harm members of our community that we want to support.

I would be very happy to have conversations about how Hachyderm’s policy, language, and enforcement were wrong, caused harm, and need to be fixed. That is a conversation worth having. I was also happy to have conversations around our stance on organizational fundraising. But the conversations about how I personally “contribute to trans genocide because I don’t support mutual aid,” are untrue, hurtful, and in my opinion, unproductive. Yes, this is extra hurtful to me, as I have experienced homelessness, and my own dependency on mutual aid as a transgender person. This is dear to my heart.

In many cases, decisions by other admins and mods were made on the assumption that I don’t support mutual aid, and this has been hard for me to reconcile.

I want to address something else, as my departure has some folks in our Hachyderm community and the broader Fediverse concerned about who will lead moderation after I leave. Moderation at Hachyderm will continue to be led by our lead moderator, as it has always been. I have never been the moderator of Hachyderm. In fact, on several occasions, I was moderated by the moderation team, including being asked to remove my post on Capitalism. This is as it should be, and I accepted the decisions of the moderation team on each occasion. In a healthy community, no one is above the rules.

Regarding the post on BlueSky, my hope was to push BlueSky towards an open identity provider such that the rest of the Fediverse could leverage the work. This would address the problem with people not owning their own identity/authentication, which is something that is important to many Hachydermians. People are already asking about this, and the AT protocol in general.

Effectively my intention was to utilize BlueSky’s hype and resources on behalf of federated identity such that people can own their own identity. Mastodon also has open issues about this. At this point I am exhausted and am abandoning BlueSky as well. I am taking a break from all social media at this time to protect my mental health.

The Hachyderm service has grown unexpectedly and I have tried my best to build a strong organization to live on without me. I have always intended on stepping down such that the collective could continue without me. Part of relinquishing control involved slowly stepping back one position at a time. It is up to the collective now to manage the service moving forward, and I deeply believe there are wonderful people in place to manage the service.

A Minute from the Moderators

Hello and welcome to April! This month we’ll be reviewing the account verification process we rolled out as well as two more classic moderation topics: how to file a report and what to do if you’re moderated.

• Account Verification
  • Mastodon account verification is like an identity service
  • Hachyderm verification makes verification visible on an account profile
  • Specialized accounts should be verified
  • We support small orgs, startups, self-run businesses, non-profits, etc.
• How to file outstanding moderation reports
  • Always include a description with your own words
  • (Almost) Always include relevant posts
  • Be clear when you are forwarding a report (or not)
• Meter yourself when filing reports
• When you’ve been moderated
  • Take warnings to heart, but they do not require an appeal
  • Always include your email when appealing an account restriction
  • Let us know if we’ve made a mistake

Account Verification

Throughout the month of March we started circulating an account verification process that launched. What does this mean, how do we use it, and what does it tell Hachydermians?

Mastodon account verification is like an identity service

Verification in the Mastodon context is similar to an ID verification service. When you build your profile you have four fields that are labeled “profile metadata”. When you include a URL that you have a rel=me link to your Mastodon profile on, then that URL highlights green with a corresponding green checkmark. In that case, the URL is verified: confirming that the person who has control of the account also has control of the domain.

Hachyderm verification makes verification visible on an account profile

Since some specialized accounts are restricted on Hachyderm, we decided to make it more immediately visible which accounts are approved or not. As part of these discussions, we also extended the verification process to even non-restricted specialized accounts.

In order to verify, specialized accounts use the process outlined on our Account Verification page which includes agreeing to the Specialized Account Expectations and using our Community GitHub issues to submit the request. Once approved, we add their Hachyderm account to an approval page we created for this process. For an example of what the end result looks like, take a look at one of our first corporate accounts, Tailscale:

Specialized accounts should be verified

As a reminder, the only accounts we’re currently requiring to be verified are:

• Corporate accounts
• Bot accounts
• Curated accounts

That said, the account verification process is open to all specialized accounts. This includes but is not limited to: non-profits, conferences, meetups, working groups, and other “entity” based accounts.

Account verification is not open to individual users at this time. That said, if you are an independent contractor or similar type of individual / self-run business please read on.

We support small orgs, startups, self-run businesses, non-profits, etc.

Please email us at admin@hachyderm.io if this applies to your account or an account you would like to create. This is the grey area for all accounts that due to size, model, or “newness” don’t fit cleanly into the account categories we’ve tried to create.

In particular, if you suspect you might fit our criteria for a corporate account but the pricing model would be a burden for you: please still reach out! We’re happy to help and try to figure something out.

How to file outstanding moderation reports

First of all: thank you to everyone for putting your trust in us and for sending reports our way. Reports on any given day or week can vary and include mixtures of spam, on and off server bad behavior, and so on. When you send reports our way, here are the main things to keep in mind so that your reports are effective.

Please see our Reporting and Communication doc, which details Hachyderm specific information, and our Report Feature doc, which shows what we see when we receive a report, for reference.

Always include a description with your own words

You should always include a description with your report. It can be as succinct as “spam” or more descriptive like “account is repeatedly following / unfollowing other users”. You should include a description even if the posts, when included, seem to speak for themselves. If you are reporting content in a language other than English, please supply translations for any dog whistles or other commentary that a translation site will likely miss in a word-for-word translation.

Mastodon also deletes posts from reports more than 30 days old. So in the event that we need to check on a user and/or domain that has been reported more than once, but infrequently, the added context can also help us capture information that is no longer present.

(Almost) Always include relevant posts

If you are reporting a user because of something they have posted, you should (almost) always include the posts themselves. When a post is reported, the post is saved in the report even if the user’s home instance deletes the posts. If the posts are not included, and the user and/or their instance mods delete the posts, then we have an empty report with no additional context.

Please feel free to use your best judgement when choosing to attach posts to a report or not. In the rare situation where you are reporting extreme content, especially with imagery, you can submit a report without posts but please ensure that you have included the context for what we can expect when we investigate the user and/or domain.

Be clear when you are forwarding a report (or not)

When you file reports for users that are off-server, you will have the option to forward the report to the user’s server admins. When a report is not forwarded, only the Hachyderm moderation team sees it. Reports forward to remote instance admins by default. If you are choosing not to forward a report for a remote user, please call it out in your comments. Although we can see when a report isn’t forwarded, the added visibility helps.

There will be times when a reported user’s infraction falls under the purview of their instance moderators and whatever server rules that user has agreed to and may be in violation of. Typically, we will only step in to moderate these situations when we need to de-federate with a remote user and/or instance completely.

Meter yourself when filing reports

We appreciate everyone who takes the time to send us a report so we can work towards keeping the Hachyderm community safe. Make sure when you are doing so that you are being mindful of your own mental health as well. As a moderation team, we are able to load balance the reports that come through to protect us individually from burnout or from seeing content that can strongly, negatively, impact us on a personal level.

Even in situations where there is yet another damaging news cycle, which in turn creates a lot of downstream effects, individuals should avoid taking on what it takes a team to tackle. In these situations, please balance the reports you send with taking steps to separate yourself from continued exposure to that content. For tips and suggestions about how to do this, please see our March Moderator Minute and our Mental Health doc.

When you’ve been moderated

Being moderated is stressful! We understand and do our best to intervene only when required to maintain community safety or when accounts need to be nudged to be in alignment with rules for their account type and/or server rules.

For additional information on the below, please see both our Reporting and Communication doc and our Moderation Actions and Appeals doc.

Take warnings to heart, but they do not require an appeal

Warnings are only used as a way to communicate with you using the admin tools. They are not accrued like a “strike” system, where something happens if you exceed a certain number. Since we only send warnings when an account needs a nudge, either a small rule clarification or similar, they do not need to be appealed. Appeals to warnings will typically receive either no action or a rejection for this reason.

Always include your email when appealing an account restriction

If your account has been restricted in some way, e.g. either frozen or suspended, then you will need to file an appeal to open a dialogue for us to reverse that decision. You should always include how we can email you in your appeal: the admin UI does not let us respond to appeals. We can only accept (repeal) or reject (keep) the decision.

Let us know if we’ve made a mistake

If we’ve made an error in moderating your account: apologies! We do our best, but mistakes can and will happen. If your account has been restricted, please file an appeal the same as in the above: by including the error and your email so we can follow up with you as needed. Once we have the information we need we can reverse the error.

A Minute from the Moderators

We’ve been working hard to build out more of the Community Documentation to help everyone to create a wonderful experience on Hachyderm. For the past month, we’ve focused most heavily on our new How to Hachyderm section. The docs in this section are:

• Preserving your mental health
• Hashtags and Content Warnings
• Accessible Posting

When you are looking at these sections, please be aware that the docs under the How to Hachyderm section are for the socialized norms around each topic and the subset of those norms that we moderate. Documentation around how to implement the features are both under our Mastodon docs section and on the main Mastodon docs. This is particularly relevant to our Content Warning sections: How To Hachyderm Content Warnings is about how content warnings are used here and on the Fediverse, whereas Mastodon User Interface Content Warnings is about where in the post composition UI you click to create a content warning.

Preserving your mental health

In our new Mental Health doc, we focus on ways that you can use the Mastodon tools for constraining content and other information. We structured the doc to answer two specific questions:

• How can people be empowered to set and maintain their own boundaries in a public space (the Fediverse)?
• What are the ways that people can toggle the default “opt-in”?

By default, social media like Mastodon / the Fediverse, opts users in to all federating content. This includes posts, likes, and boosts. Depending on your needs, you may want to opt out of some subsets of that content either on a case-by-case basis, by topic, by source, or by type. Remember:

You can opt out of any content for any reason.

For example, you may want to opt out of displaying media by default because it is a frequent trigger. Perhaps the specific content warnings you need aren’t well socialized. Maybe you are sensitive to animated or moving media. That said, perhaps media isn’t a trigger - you just don’t like it. Regardless of your reason, you can change this setting (outlined in the doc) whenever you wish and however often as meets your needs.

Hashtags and Content Warnings

Our Hashtags and Content Warnings docs are to help Hachydermians better understand both what these features are and the social expectations around them. In both cases, there are some aspects of the feature that people have encountered before: hashtags in particular are very common in social media and content warnings mirror other features that obscure underlying text on sites like Reddit (depending on the subreddit) and tools like Discord.

Both of these features have nuance to how they’re used on the Fediverse that might be new for some. On the Fediverse, and on Hachyderm, there are “reserved hashtags”. These are hashtags that are intended only for a specific, narrow, use. The ones we moderate on Hachyderm are FediBlock, FediHire, and HachyBots. For more about this, please see the doc.

Content warnings are possibly less new in concept. The content warning doc focuses heavily on how to write an effective content warning. Effective content warnings are important as you are creating a situation for someone else to opt in to your content. This requires consent, specifically informed consent. A well written content warning should inform people of the difference between “spoilers”, “Doctor Who spoilers”, and “Doctor Who New Year’s Special Spoilers”. The art of crafting an effective content warning is balancing what information to include while also not making the content warning so transparent that the content warning is the post.

Notably, effective content warnings feature heavily in our Accessible Posting doc.

Accessible Posting

Our Accessible Posting doc is an introductory guide to different ways to improve inclusion. It is important to recognize there are two main constraints for this guide:

• It is an introductory guide
• The Mastodon tools

As an introductory guide, it does not cover all topics of accessibility. As a guide that focuses on Mastodon, the guide discusses the current Mastodon tools and how to fully utilize them.

As an introductory guide, our Accessibility doc primarily seeks to help users develop more situational awareness for why there are certain socialized patterns for hashtags, content warnings, and posting media. We, as moderators of Hachyderm, do not expect anyone to be an expert on any issue that the doc covers. Rather, we want to help inspire you to continue to learn about others unlike yourself and see ways that you can be an active participant in creating and maintaining a healthy, accessible, space on the Fediverse.

Content warnings feature heavily on this doc. The reason for this is Mastodon is a very visual platform, so the main ways that you are connecting with others who do not have the same experience of visual content is by supplying relevant information.

There will always be more to learn and more, and better, ways to build software. For those interested in improving the accessibility features of Mastodon, we recommend reviewing Mastodon’s CONTRIBUTING document.

More to come

We are always adding more docs! Please check the docs pages frequently for information that may be useful to you. If you have an idea for the docs, or wish to submit a PR for the docs, please do so on our Community repo on GitHub.

April will mark one month since we launched the Nivenly Foundation, Hachyderm’s parent org. Nivenly’s website is continuing to be updated with information about how to sponsor or become a member. For more information about Nivenly, please see Nivenly’s Hello World blog post.

The creation of Nivenly also allowed us to start taking donations for Hachyderm and sell swag. If you are interested in donating, please use either our GitHub Sponsors or one of the other methods that we outline on our Thank You doc. For Hachyderm swag, please check out Nivenly’s swag store .

Decaf Ko-Fi: Launching GitHub Sponsors et al

Since our massive growth at the end of last year, many of you have asked about ways to donate beyond Nóva’s Ko-Fi. There were a few limitations there, notably the need to create an account in order to donate. There were a few milestones we needed to hit before we could do this properly, notably we needed to have an EIN in order to properly receive donations and pay for services (as an entity).

Well that time has come! Read on to learn about how you can support Hachyderm either directly or via Hachyderm’s parent organization, the Nivenly Foundation.

First things first: GitHub Sponsors

Actual Octocat from our approval email

As of today the Hachyderm GitHub Sponsors page is up and accepting donations! Using GitHub Sponsors you can add a custom amount and donate either once or monthly. There are a couple of donation tiers that you can choose from as well if you are interested in shoutouts / thank yous either on Hachyderm or on our Funding and Thank You page. In both cases we’d use your GitHub handle for the shoutout.

The shoutouts and Thank You page

#ThankYouThursday is a hashtag we’re creating today to thank users for their contributions. Most posts for #ThankYouThursday happen on Hachyderm’s Hachyderm account, but higher donations will be elible for shoutouts on Kris Nóva’s Hachyderm.

• $7/mo. and higher
  • Get a sponsor badge on your GitHub profile
• $25/mo. and higher or $100 one-time and higher
  • Get a sponsor badge on your GitHub profile
  • Get a shoutout on the Hachyderm account’s quarterly #ThankYouThursday
• $50/mo. and higher or $300 one-time and higher
  • Get a sponsor badge on your GitHub profile
  • Get a shoutout on the Kris Nóva’s account’s quarterly #ThankYouThursday
• $1000 one-time and higher
  • Get a sponsor badge on your GitHub profile
  • Get a shoutout on the Hachyderm account’s quarterly #ThankYouThursday
  • Be added to the Thank You List on our Funding page
• $2500 one-time and higher
  • Get a sponsor badge on your GitHub profile
  • Get a shoutout on Kris Nóva’s quarterly #ThankYouThursday

(All above pricing in USD.)

A couple of important things about the above:

• All public announcements are optional. You can choose to opt-out by having your donation set to private.
• By default we’ll use your GitHub handle for shoutouts. This is easier than reconciling GitHub and Hachyderm handles.
• We may adjust the tiers to make the Thank Yous more frequent.

Right now the above tiers are our best guess, but we may edit the #ThankYouThursday thresholds in particular so that we can keep a sustainable cadence. Thank you for your patience and understanding with this ❤️

And now an update for the Nivenly Foundation

For those who don’t know: the Nivenly Foundation is the non-profit co-op that we’re founding for Hachyderm and other open source projects like Aurae. The big milestone we reached here is that 1 ) we’re an official non-profit with the State of Washington and 2 ) we have a nice, shiny, EIN which allowed us to start accepting donations to both the Nivenly Foundation as well as its two projects: Aurae and Hachyderm. For visibility, here are all the GitHub sponsor links in one place:

• Nivenly GitHub Sponsor Page
• Hachyderm GitHub Sponsor Page
• Aurae GitHub Sponsor Page

It is also possible to give a custom one-time donation to Nivenly via Stripe:

• Stripe One-Time Donation

Right now only donations are open for Nivenly, Aurae, and Hachyderm. After we finalize Nivenly’s launch, Nivenly memberships will also be available for individuals, maintainers, and what we call trade memberships for companies, businesses, and business-like entities.

What do Nivenly Memberships mean for donations?

Right now, donations and memberships are separate. That means that you can donate to Hachyderm and, once available, join Nivenly as two separate steps. As Nivenly’s largest project, providing governance and funding for Hachyderm uses almost all of Nivenly’s donations. As we grow and include more projects this is likely to shift over time. As such, we are spinning up an Open Collective page for Nivenly that will manage the memberships and also provide a way for us to be transparent about our budget as we grow. Our next two big milestones:

• What you’ve all been waiting for: the public release of the governance model (almost complete)
• What we definitely need: the finalization of our 501(c)3 paperwork with the IRS (in progress)

As we grow we’ll continue to post updates. Thank you all so much for your patience and participation 💕

P.S. and update: What’s happening with Ko-fi?

We are currently moving away from Kris Nóva’s Ko-fi as a funding source for Nivenly and Hachyderm et al. We’ve created a new Ko-fi account for the Nivenly Foundation itself:

• Nivenly Foundation Ko-fi

Kris Nóva’s Ko-fi is still live to give people time to migrate Nivenly-specific donations (including those for Hachyderm and Aurae) from her Ko-fi to either GitHub sponsors, Nivenly’s Ko-fi, Stripe or starting a Nivenly co-op general membership via Nivenly’s Open Collective page as those become ready (which should be soon). We’ll still be using Nivenly-specific funds from her Ko-fi for Nivenly for the next 30-60 days and will follow up with an update as we start to stop that (manual 😅) process.

Growth and Sustainability

Thank you to everyone who has been patient with Hachyderm as we have had to make some adjustments to how we do things. Finding ourselves launched into scale has impacted our people more than it has impacted our systems.

I wanted to provide some visibility into our intentions with Hachyderm, our priorities, and immediate initiatives.

Transparency Reports

We intend on offering transparency reports similar to the November Transparency Report from SFBA Social. It will take us several weeks before we will be able to publish our first one.

The immediate numbers from the administration dashboard are below.

Donations

On January 1st, 2023 we will be changing our financial model.

Hachyderm has been operating successfully since April of 2022 by funding our infrastructure from the proceeds of Kris Nóva’s Twitch presence.

In January 2023 we will be rolling out a new financial model intended to be sustainable and transparent for our users. We will be looking into donation and subscription models such as Patreon at that time.

From now until the end of the year, Hachyderm will continue to operate using the proceeds of Kris Nóva’s Twitch streams, and our donations through the ko-fi donation page.

Governing Body

We are considering forming a legal entity to control Hachyderm in January 2023.

At this time we are not considering a for-profit corporation for Hachyderm.

The exact details of what our decision is, will be announced as we come to conviction and seek legal advice.

User Registration

At this time we do not have any plans to “cap” or limit user registration for Hachyderm.

There is a small chance we might temporarily close registration for small limited periods of time during events such as the DDoS Security Threat.

To be clear, we do not plan on rolling out a formal registration closure for any substantial or planned period of time. Any closure will be as short as possible, and will be opened up as soon as it is safe to do so.

We will be reevaluating this decision continuously. If at any point Hachyderm becomes bloated or unreasonably large we will likely change our decision.

User Registration and Performance

At this time we do not believe that user registration will have an immediate or noticeable impact on the performance of our systems. We do not believe that closing registration will somehow “make Hachyderm faster” or “make the service more reliable”.

We will reevaluating this decision continuously. If at any point the growth patterns of Hachyderm changes we will likely change our decision.

Call for Volunteers

We will be onboarding new moderators and operators in January to help with our service. To help with that, we have created a short Typeform to consolidate all the volunteer offers so it is easier for us to reach back out to you when we’re ready:

Hachyderm Interest Form

The existing teams will be spending the rest of December cleaning up documentation, and building out this community resource in a way that is easy for newcomers to be self sufficent with our services.

As moderators and infrastructure teams reach a point of sustainability, each will announce the path forward for volunteers when they feel the time is right.

The announcements page on this website, will be the source of truth.

Our Promise to Our users

Hachyderm has signed The Mastodon Server Covenant which means we have given our commitment to give users at least 3 months of advance warning in case of shutting down.

My personal promise is that I will do everything in my power to support our users any way I can that does not jeopardize the safety of other users or myself.

We will be forming a broader set of governance and expectation setting for our users as we mature our services and documentation.

Sustainability

I wanted to share a few thoughts on sustainability with Hachyderm.

Part of creating a sustainable service for our users will involve participation from everyone. We are asking that all Hachydermians remind themselves that time, patience, and empathy are some of the most effective ways in creating sustainable services.

There will be some situations where we will have to make difficult decisions with regard to priority. Often times the reason we aren’t immediately responding to an issue isn’t because we are ignoring the issue or oblivious to it. It is because we have to spend our time and effort wisely in order to keep a sustainable posture for the service. We ask for patience as it will sometimes take days or weeks to respond to issues, especially during production infrastructure issues.

We ask that everyone reminds themselves that pressuring our teams is likely counter productive to creating a sustainable environment.

Leaving the Basement

This post has taken several weeks in the making to compile. My hope is that this captures the vast majority of questions people have been asking recently with regard to Hachyderm.

To begin, I would like to start by introducing the state of Hachyderm before the migration, as well as introduce the problems we were experiencing. Next, I will cover the root causes of the problems, and how we found them. Finally, I will discuss the migration strategy, the problems we experienced, and what we got right, and what can be better. I will end with an accurate depiction of how hachyderm exists today.

State of Hachyderm: Before

Hachyderm obtained roughly 30,000 users in 30 days; or roughly 1 new user every 1.5 minutes for the duration of the month of November.

I documented 3 medium articles during the month, each with the assumption that it would be my last for the month.

• November 3rd, 720 users Operating Mastodon, Privacy, and Content
• November 13th, 6,000 users Hachyderm Infrastructure
• November 25th, 25,000 users Experimenting with Federation and Migrating Accounts

Here are the servers that were hosting Hachyderm in the rack in my basement, which later became known as “The Watertower”.

It is important to note that all of the servers are used hardware, and all of the drives are SSDs.

“The Watertower” sat behind a few pieces of network hardware, including large business fiber connection in Seattle, WA. Here are the traffic patterns we measured during November, and the advertised limitations from our ISP.

Our busiest traffic day was 11/21/22 where we processed 999.80 GiB in RX/TX traffic in a single day. During the month of November we averaged 36.86 Mbps in traffic with samples taken every hour.

The server service layout is detailed below.

Problems in Production

For the vast majority of November, Hachyderm had been stable. Most users reported excellent experience, and our systems remained relatively healthy.

On November 27th, I filed the 1st of what would become 21 changelogs for our production infrastructure.

The initial report was failing images in production. The initial investigation lead our team to discover that our NFS clients were behaving unreasonably slow.

We were able to prove that NFS was “slow” by trying to navigate to a mounted directory and list files. In the best cases results would come back in less than a second. In the worst cases results would take 10-20 seconds. In some cases the server would lock up and a new shell would need to be established; NFS would never return.

I filed a changelog, and mutated production. This is what became the first minor change in a week long crisis to evacuate the basement.

We were unable to fix the perceived slowness with NFS with my first change.

However we did determine that we had scaled our compute nodes very high in the process of investigating NFS. Load averages on Yakko, Wakko, and Dot were well above 1,000 at this time.

Each Yakko, Wakko, and Dot were housing multiple systemd units for our ingress, default, push, pull, and mailing queues – as well as the puma web server hosting Mastodon itself.

At this point Alice was serving our media over NFS, postgres, redis, and a lightweight Nginx proxy to load balance across the animaniacs (Yakko, Wakko, and Dot).

The problems began to cascade the night of the 27th, and continued to grow worse by the hour into the night.

• HTTP(s) response times began to degrade.
• Postgres response times began to degrade.
• NFS was still measurably slow on the client side.

The main observation was that the service would “flap”, almost as if it was deliberately toying with our psychology and our hope.

We would see long periods of “acceptable” performance when the site would “settle down”. Then, without warning, our alerts would begin to go off.

Hachyderm hosts a network of edge or point of presence (PoP) nodes that serve as a frontend caching mechanism in front of core.

During the “spikes” of failure, the edge Nginx logs began to record “Connection refused” messages.

The trend of “flapping” availability continued into the night. The service would recover and level out, then a spike in 5XX level responses, and then ultimately a complete outage on the edge.

This continued for several days.

A Note on Empathy

It is important to note that Hachyderm had grown organically over the month of November. Every log that was being captured, every graph that was consuming data, every secret, every config file, every bash script – all – were a consequence of reacting to the “problem” of growth and adoption.

I call this out, because this is very akin to most of the production systems I deal with in my career. It is important to have empathy for the systems and the people who work on them. Every large production is a consequence of luck. This means that something happened that caused human beings to flock to your service.

I am a firm believer that no system is ever “designed” for the consequences of high adoption. This is especially true with regard to Mastodon, as most of our team has never operated a production Mastodon instance before. To be candid, it would appear that most of the internet is in a similar situation.

We are all experimenting here. Hachyderm was just “lucky” to see adoption.

There is no such thing as both a mechanistic and highly adopted system. All systems that are a consequence of growth, will be organic, and prone to the symptoms of reactive operations.

In other words, every ugly system is also a successful system. Every beautiful system, has never seen spontaneous adoption.

Finding Root Causes

By the 3rd day we had roughly 20 changelogs filed.

Each changelog capturing the story of a highly motivated and extremely hopeful member of the team believing they had once and for all identified the bottleneck. Each, ultimately failing to stop the flapping of Hachyderm.

I cannot say enough good things about the team who worked around the clock on Hachyderm. In many cases we were sleeping for 4 hours a night, and bringing our laptops to bed with us.

• @Quintessence wins the “Universe’s best incident commander” award.
• @Taniwha wins the “Best late night hacker and cyber detective” award.
• @hazelweakly wins the “Extreme research and googling cyberhacker” award.
• @malte wins the “Best architect and most likely to remain calm in a crisis” award.
• @dma wins the “Best scientist and graph enthusiast” award.

After all of our research, science, and detection work we had narrowed down our problem two 2 disks on Alice.

/dev/sdg # 2Tb "new" drive
/dev/sdh # 2Tb "new" drive

The IOPS on these two particular drives would max out to 100% a few moments before the cascading failure in the rack would begin. We had successfully identified the “root cause” of our production problems.

Here is a graphic that captures the moment well. Screenshot taken from 2am Pacific on November 30th, roughly 3 days after production began to intermittently fail.

It is important to note that our entire production system, was dependent on these 2 disks, as well as our ZFS pool which was managing the data on the disks,

[novix@alice]: ~>$ df -h
Filesystem                Size  Used Avail Use% Mounted on
dev                        63G     0   63G   0% /dev
run                        63G  1.7G   62G   3% /run
/dev/sda3                 228G  149G   68G  69% /
tmpfs                      63G  808K   63G   1% /dev/shm
tmpfs                      63G   11G   53G  16% /tmp
/dev/sdb1                 234G  4.6G  218G   3% /home
/dev/sda1                1022M  288K 1022M   1% /boot/EFI
data/novix                482G  6.5G  475G   2% /home/novix
data                      477G  1.5G  475G   1% /data
data/mastodon-home        643G  168G  475G  27% /var/lib/mastodon
data/mastodon-postgresql  568G   93G  475G  17% /var/lib/postgres/data
data/mastodon-storage     1.4T  929G  475G  67% /var/lib/mastodon/public/system
tmpfs                      10G  7.5G  2.6G  75% /var/log 

Both our main media block storage, and our main postgres database was currently housed on ZFS. The more we began to correlate the theory, the more we could correlate slow disks to slow databases responses, and slow media storage. Eventually our compute servers and web servers would max out our connection pool against the database and timeout. Eventually our web servers would overload the media server and timeout.

The timeouts would cascade out to the edge nodes and eventually cause:

• 5XX responses in production.
• Users hitting the “submit” button as our HTTP(s) servers would hang “incomplete” resulting in duplicate posts.
• Connection refused errors for every hop in our systems.

We had found the root cause. Our disks on Alice were failing.

Migration 1: Digital Ocean

We had made the decision to evacuate The Watertower and migrate to Hetzner weeks prior to the incident. However it was becoming obvious that our “slow and steady” approach to setting up picture-perfect infrastructure in Hetzner wasn’t going to happen.

We needed off Alice, and we needed off now.

A few notable caveats about leaving The Watertower.

1. Transferring data off The Watertower was going to take several days with the current available speed of the disks.
2. We were fairly confident that shutting down production for several days wasn’t an option.
3. Our main problem was getting data off the disks.

Unexpectedly I received a phone call from an old colleague of mine @Gabe Monroy at Digital Ocean. Gabe offered to support Hachyderm altruistically and was able to offer the solution of moving our block storage to Digital Ocean Spaces for object storage.

Thank you to Gabe Monroy, Ado Kukic, and Daniel Hix for helping us with this path forward! Hachyderm will forever be grateful for your support!

There was one concern, how were we going to transfer over 1Tb of data to Digital Ocean on already failing disks?

One of our infrastructure volunteers @malte had helped us come up with an extremely clever solution to the problem.

We could leverage Hachyderm’s users to help us perform the most meaningful work first.

Solution: NGINX try_files

Malte’s model was simple:

1. We begin writing data that is cached in our edge nodes directly to the object store instead of back to Alice.
2. As users access data, we can ensure that it will be be taken of Alice and delivered to the user.
3. We can then leverage Mastodon’s S3 feature to write the “hot” data directly back to Digital Ocean using a reverse Nginx proxy.

We can point the try_files directive back to Alice, and only serve the files from Alice once as they would be written back to S3 by the edge node accessing the files. Read try_files documentation.

In other words, the more that our users accessed Hachyderm, the faster our data would replicate to Digital Ocean. Conveniently this also meant that we would copy the data that was being immediately used first.

We could additionally run a slow rclone for the remaining data that is still running 2+ days later as I write this blog post.

This was the most impressive solution I have seen to a crisis problem in my history of operating distributed systems. Our users, were able to help us transfer our data to Digital Ocean, just by leveraging the service. The more they used Hachyderm, the more we migrated off Alice’s bad disks.

Migration 2: Hetzner

By the time the change had been in production for a few hours, we all had noticed a substantial increase in our performance. We were able to remove NFS from the system, and shuffle around our Puma servers, and sidekiq queues to reduce load on Postgres.

Alice was serving files from the bad disks, however all of our writes were now going to Digital Ocean.

While our systems performance did “improve” it was still far from perfect. HTTP(s) requests were still very slowly, and in cases would timeout and flap.

At this point it was easy to determine that Postgres (and it’s relationship to the bad disks) was the next bottleneck in the system.

Note: We still have an outstanding theory that ZFS, specifically the unbalanced mirrors, is also a contributing factor. We will not be able to validate this theory until the service is completely off Alice.

It would be slightly more challenging coming up with a clever solution to get Postgres off Alice.

On the morning of December 1st we finished replicating our postgres data across the atlantic onto our new fleet of servers in Hetzner.

• Nixie (Alice replacement)
• Freud (Yakko)
• Fritz (Wakko)
• Franz (Dot)

We will be publishing a detailed architecture on the current system in Hetzner as we have time to finalize it.

Our team made an announcement that we were shutting production down, and scheduled a live stream to perform the work.

The video of the cutover is available to watch directly on Twitch.

NodeJS and Mastodon

The migration would not be complete without calling out that I was unable to build the Mastodon code base on our new primary Puma HTTP server.

After what felt like an eternity we discovered that we needed to recompile the NodeJS assets.

cd /var/lib/mastodon
NODE_OPTIONS=--openssl-legacy-provider
RAILS_ENV=production bundle exec rails assets:precompile

Eventually we were able to build and bring up the Puma server which was connected to the new postgres server.

We moved our worker queues over to the new servers in Hetzner.

The migration was complete.

State of Hachyderm: After

To be candid, Hachyderm “just works” now and we are serving our core content within the EU in Germany.

There is an ever-growing smaller and smaller amount of traffic that is still routing through Alice as our users begin to access more and more obscure files.

Today we have roughly 700Gb of out 1.2Tb of data transferred to Digital Ocean.

We will be destroying the ZFS server in Alice, and replacing the disks as soon as we can completely take The Watertower offline.

On our list of items to cover moving forward:

• Offer a detailed public resource of our architecture in Hetzner complete with Mastodon specific service breakdowns.
• Build a blog and community resource such that we can begin documenting our community and bringing new volunteers on board.
• Take a break, and install better monitoring on our systems.
• Migrate to NixOS or Kubernetes depending on the needs of the system.
• Get back to working on Aurae, now with a lot more product requirements than we had before.

Conclusion

We suffered from pretty common pitfalls in our system. Our main operational problems stemmed from scaling humans, and not our knowledge of how to build effective distributed systems. We have observability, security, and infrastructure experts from across Silicon Valley working on Hachyderm and we were still SSHing into production and sharing passwords.

In other words, our main limitations to scale were managing people, processes, and organizational challenges. Even determining who was responsible for what, was a problem within itself.

We had a team of experts without any formal precedent working together, and no legal structure or corporate organization to glue us together. We defaulted back to some bad habits in a pinch, and also uncovered some exciting new patterns that were only made possible because of the constraints of the fediverse.

Ultimately I believe that myself, and the entire team is convinced that the future of the internet and social is going to be in large collaborative operational systems that operate in a decentralized network.

We made some decisions during the process, such as keeping registrations open during the process that I agree with. I think I would make the same decisions again. Our limiting factor in Hachyderm had almost nothing to do with the amount of users accessing the system as much as it did the amount of data we were federating. Our system would have flapped if we had 100 users, or if we had 1,000,000 users. We were nowhere close to hitting limits of DB size, storage size, or network capacity. We just had bad disks.

I think the biggest risk we took was onboarding new people to a slow/unresponsive service for a few days. I am willing to accept that as a good decision as we are openly experimenting with this entire process.

I have said it before, and I will say it again. I believe in Hachyderm. I believe we can build a beautiful and effective social media service for the tech industry.

The key to success will be how well we experiment. This is the time for good old fashioned computer science, complete with thoughtful hypothesis and detailed observability to validate them.

Incidents

Security incident: Redis cache exposed to public internet

Background

Between July 9 and July 16, 2023, one of Hachyderm’s Redis cache servers was exposed to the public internet. On July 16, 2023, the Hachyderm Infrastructure team identified a misconfiguration of our firewall on the cache server which allowed access to the redis interface from the public Internet. After a routine system update, the nftables firewall service was not brought up automatically after a restart, which exposed the Redis cache to the internet for a period of seven days.

During the exposure, an unknown third party attempted to reconfigure our Redis server to act as a replica for a Redis server they controlled. Due to this change, a read-only mode was enabled on Hachyderm Redis and no further data was written.

Normally, Hachyderm servers run nftables to block all except necessary traffic from the Internet. We leverage Tailscale for server-to-server communication and only expose ports to the Internet as needed to run Mastodon and administer the systems.

As of July 16, 2023 11:17 UTC, the Hachyderm team has corrected the configuration on our systems and blocked external actors from accessing this Redis instance. While we do not have any direct evidence the information in the cache was deliberately exfiltrated, because this was exposed to the public internet, we assume the data was compromised.

Impact

Highly sensitive information like passwords, private keys, and private posts were NOT exposed as part of this incident. No action is required from the user.

The affected Redis cache stored the following types of information with a 10 minute time-to-live before getting deleted:

• Logins using /auth/sign_in will cache inputted email addresses and used IP addresses for login throttling. Note that if you had a cached session during this period, no IPs or email-addresses would have been included.
• Rails-generated HTML content.
• Some UI-related settings for individual users (examples being toggles for reducing motion, auto play gifs, and the selected UI font).
• Public posts rendered by Mastodon in the affected period.
• Other non-critical information like emojis, blocked IPs, status counts, and other normally public information of the instance.

We do not have sufficient monitoring to confirm precisely when the compromise occurred. We also have no confirmation if any of the above data was actually sent to a third party, but since the information was available to them, we assume the data was compromised. But since the adversary turned on read-replica mode disabling writes, and Mastodon’s cache having a time to live of 10 minutes, it would have severely limited the amount of information leaked in this period.

Timeline

Analysis

What went well & where did we get lucky

• We got lucky that it was the caching redis server, which primarily holds Rails generated HTML content, UI related settings per user, and rack based login throttling.
• No user data outside of a subset of IP addresses and Emails from people using the login form in the compromised period were possibly shared.
• Redis had a TTL of ten (10) minutes on any data in this cache.
• Redis was put into a READONLY mode when the compromise occurred, so it is likely no data was pushed to the adversary after the timestamp of the compromise. This, coupled with the ten minute cache, caused the cache itself to empty fairly quickly.

What didn’t go well

• Process: While we have a standard process for updating Mastodon, and while our servers are version-controlled into git, they are individually unique creations, which makes it challenging to understand if a server is configured correctly because each server can be just a little different.
• System: We don’t leverage authentication or restrictive IP block binds on our Redis server, so once the firewall was down, Redis would become available on the Internet and trivial to connect to and see what data it contained.
• It took us a long time to identify the issue:
  • Observability: We don’t currently have detective control to alert us if a critical configuration on a server is set correctly or not.
  • Observability: Furthermore, we didn’t have any outlier detection or redis alerts set up to notify us that Redis had gone into read only mode.
• Observability: Due to how journalctl had been set up to rotate logs by size, and the explosive amount of RedisCacheStore: write_entry failed entries generated per successful page load, we quickly lost the ability to look back on our log history to see the exact date the access happened.

Corrective Actions

The Hachyderm infrastructure team is taking/will take the following actions to mitigate the impact of this incident:

Moderation Postmortem

Hello Hachydermians! There has been a lot of confusion this week, so we’re writing up this blog post to be both a postmortem of sorts and a single source of truth. This is partly to combat some of the problems generated by hearsay: hearsay generates more Things To Respond To than Things That Actually Happened. As a result, this post is a little longer than our norm.

Moderation Incident

(A note to the broader, non-tech industry, members of our community: “Incident” here carries similar context and meaning to an “IT Incident” as we are a tech-oriented instance. Postmortems for traditional IT incidents are also in this section.)

A Short, Confusing Timeline

On 24 April 2023 the Hachyderm Moderation team received a request to review our Fundraising Policy via a GitHub Issue. The reason for the request was to ensure there was a well understood distinction between Mutual Aid and Fundraising. Although our Head Moderator responded to the thread with the constraints we use when developing new rules, some of the hearsay we started to see in the thread the user linked raised some flags that something else was happening.

In order to determine what happened, we needed to dive into various commentary before arriving at a potential root cause (and we eventually determined this was indeed the correct root cause). While a few of our moderators working on this, our founder and now-former admin Kris Nóva was requested, either directly or indirectly, to make statements on transgender genocide (she is herself openly transgender) and classism.

These issues are important, we want to be unequivocally clear. Kris Nóva is transgender and has been open about her experiences with homelessness and receiving mutual aid. The Hachyderm teams are also populated, intentionally, with a variety of marginalized individuals that bring their own lived experiences to our ability to manage Hachyderm’s moderation and infrastructure teams. That said: it was not immediately apparent that these requests were initially connected to the originating problem. In fact, it caused additional resources to be used trying to determine if there was a secondary problem to address. This resulted in a delay in actual remediation.

The Error Itself

On 27 Mar 2023 the Hachyderm Moderation Team received a report that indicated that an account may have been spamming the platform. When the posts were reviewed at the time of the report, it did trigger our spam policy. When we receive reports of accounts seeking funds, we try to validate the posts to check for common issues like phishing and so forth, as well as checking post volume and pattern to determine if the account is posting in a bot-like way, and so forth. At the time the report was moderated, the result was that the posting type and/or pattern was incorrectly flagged as spam and we requested the account stop posting that type of post. Once we became aware of the situation, the Hachyderm Moderation team followed up with our Hachydermian to ensure that they knew that they could post their requests for Mutual Aid, apologized for the error, and did our best to let them know we were here if there was anything else we could do to help them feel warm and welcome on our instance.

Lack of public statement

There have been some questions around the lack of public statement regarding the above. There are two reasons for this. First and foremost, this is because situations involving moderation are between the moderation team and the impacted person. Secondly, we must always take active steps to protect against negative consequences that can come with all the benefits of being a larger instance.

How Errors in Moderation are Handled at Hachyderm

Depending on the error, one or both of the following occurs:

• Follow up with the user to rectify the situation
• Review policy to ensure it doesn’t happen again

This is because of two enforced opinions of the Hachyderm Moderation team:

• Moderation reports filed by users are reports of harm done.
  • To put it another way: if a user needs to file a report of hateful content, then they have already seen that content to report it.
• All moderation mistakes are also harm done.

For the latter, we only follow up with the user if 1) they request and/or 2) we have reason to believe it would not increase the harm done. All Hachyderm Moderator and Hachydermian interactions are centered on harm mitigation. Rectifying mistakes in moderation are about the impacted person and not ego on the part of the specific moderator who made the mistake.

To put it another way, the Hachyderm Moderation team exists to serve the Hachyderm Community. This means that we will apologize to the user as part of harm mitigation. We will not as part of “needing to have our apology accepted” or to “be seen as apologizing”. These latter two go against the ethos of Hachyderm Moderation Strategy.

Inter-instance Communication and Hachyderm

Back when we took on the Twitter Migration in Nov 2022, we started to overcommunciate with Hachydermians that we were going to start using email and GitHub Issues (in addition to moderation reports) to accommodate our team scaling. As part of the changes we made, we also started making changes to reflect this in the documentation, as well as including how other instances can reach out to us if needed. It was our own pattern that if we needed to reach out to another instance, we used the email address they listed on their instance page. This is because we didn’t want to assume “the name on the instance” was “the” person to talk to. There are likely other instances like ours that have multiple people involved. This is reinforced by the fact that the “name” is actually populated by default by the person who originally installed the software on the server(s).

That said, we recently made a connection with someone who has grown their instance in the Fediverse for quite some time and has been helping to make us aware of the pre-existing cultural and communication norms in this space. In the same way it was natural for us to check for the existence of instance documentation to find their preferred way to communicate, it was unnatural for some of the existing instances to do so. Instead, it seems there are pre-existing cultural norms in the space we weren’t aware of, the impact of this is that some instances knew how to reach us and others did not.

We have been taking feedback from the person we connected with so that we can balance the needs of the existing communication patterns and norms of the Fediverse, while not accidentally creating a situation where a communication method ends up either too silo’ed or not appropriately visible due to our team structures.

TLS Expires: media.hachyderm.io

On February 28th, 2023 at approximately 01:55 UTC Hachyderm experienced a service degradation in which images failed to load in production.

We were able to quickly identify the root cause as expired TLS certificates in production for media.hachyderm.io

Context

Hachyderm TLS certificates are still managed manually, and are very clearly out of sprawling out of control due to our rapid growth. There are many certificates on various servers that have had config copied from one server to another as we grew into our current architecture.

The alert notification was missed, and the media.hachyderm.io TLS privkey.pem and fullchain.pem material expired causing the service degradation.

Timeline

• Feb 28th 01:52 @quintessence First report of media outages
• Feb 28th 01:54 @nova Confirms media is broken from remote proxy in EU
• Feb 28th 01:56 @nova Appoints @quintessence as incident commander
• Feb 28th 01:57 @nova Confirms TLS expired on media.hachyderm.io
• Feb 28th 02:30 @nova Live streaming fixing TLS

Shortly after starting the stream we discovered that the Acme challenge was not working because the media.hachyderm.io DNS record was pointed to CNAME hachyderm.io and the proxy was not configured to manage the request. In the past we have worked around this by editing the CDN on the East coast which is where the Acme challenge will resolve.

In this case we changed the media.hachyderm.io DNS record to point to A <ip-of-fritz> which is where the core web server was running.

We re-ran the renew process and it worked!

sudo -E certbot renew

We then re-pointed media.hachyderm.io back to CNAME hachyderm.io.

Next came the scp command to move the new cert material out to the various CDN nodes and restart nginx.

# Copy TLS from fritz -> CDN host
scp /etc/letsencrypt/archive/media.hachyderm.io/* root@<host>:/etc/letsencrypt/archive/media.hachyderm.io/

# Access root on the CDN host
ssh root@<host>

# Private key (on CDN host)
rm -f /etc/letsencrypt/live/media.hachyderm.io/privkey.pem
ln -s /etc/letsencrypt/archive/media.hachyderm.io/privkey3.pem /etc/letsencrypt/live/media.hachyderm.io/privkey.pem

# Fullchain (on CDN host)
rm -f /etc/letsencrypt/live/media.hachyderm.io/fullchain.pem
ln -s /etc/letsencrypt/archive/media.hachyderm.io/fullchain3.pem /etc/letsencrypt/live/media.hachyderm.io/fullchain.pem

The full list of CDN hosts:

• cdn-frankfurt-1
• cdn-fremont-1
• sally
• esme

Restarting nginx on each of the CDN hosts was able to fix the problem.

# On a CDN host
nginx -t               # Test the config
systemctl reload nginx # Reload the service

# On your local machine 
emacs /etc/hosts       # Point "hachyderm.io" and "media.hachyderm.io" to IP of CDN host

# Check your browser for working images

Impact

• Full image outage across the site in all regions.
• A stressful situation interrupting dinner and impacting the family.
• Even more chaos and confusion with certificate material.

Lessons Learned

• We still have outstanding legacy certificate management problems.

Things that went well

• We had a quick report, and the mean time to resolution was <60 mins.

Things that went poorly

• The certs are in an even more chaotic state.
• There was no alerting that the images broke.
• There was a high stress situation that impacting our personal lives.

Where we got lucky

• I still had access to the servers, and was able to remedy the situation from existing knowledge.

Action items

• We need to destroy the vast majority of nginx configurations and domains in production
• We need to destroy all TLS certs and re-create them with a cohesive strategy
• We need a better way to perform the Acme challenge that doesn’t involve changing DNS around the globe
• Nóva to send list of domains to discord to destroy

Fritz Timeouts

On January 7th, 2023 at approximately 22:26 UTC Hachyderm experienced a spike in HTTP response times as well as a spike in 504 Timeouts across the CDN.

Working backwards from the CDN to fritz we discovered another cascading failure.

Context

There is a fleet of CDN nodes around the world, commonly referred to as “POP” servers (Point of Presence) or even just “The CDN”. These servers reverse proxy over dedicated connections back to our core infrastructure.

These CDN servers served content timeouts at roughly 22:20:00 UTC.

These CDN servers depend on the mastodon-streaming service to offer websocket connections.

Impact

• Total streaming server outage reported in Discord (Uptime Robot)
• Slow/Timeouts reported by users in Twitch chat
• Nóva noticed slow/timeouts on her phone

HTTP Response Times measured > 3s

Background

We received some valuable insight from @ThisIsMissEm who has experience with both node.js websocket servers and the mastodon codebase, which can be read here in HackMD.

An important takeaway from this knowledge is that the mastodon-streaming service and the mastodon-web service will not rate limit if they are communicating over localhost.

In other words, you should be scheduling mastodon-streaming on the same node you are running mastodon-web.

We believe that the way the streaming API works, that if there is a “large event” such as having a post go out by a largely followed account it can cause a cascading effect on everyone connected via the streaming API.

A good metric to track would actually be the percentage of connections that a single write is going to. If the mastodon server has one highly followed user, a post by them, especially in a “busy” timezone for the instance, will result in unbalanced write behaviours, where one message posted will result in iterating over a heap more connections than others (one per follower who’s connected to streaming), so you can end up doing 40,000 network writes very easily, locking up node.js temporarily from processing disconnections correctly.

We believe that the streaming API began to drop connections which cascaded out to the CDN nodes via the mastodon-web service.

We can correlate this theory by connecting observe logged lines to the Mastodon code bash.

Logs from mastodon-streaming on Fritz

06-4afe-a449-a42f861855b2 Tried writing to closed socket
33-414d-9143-6a5080bd6254 Tried writing to closed socket
33-414d-9143-6a5080bd6254 Tried writing to closed socket
06-4afe-a449-a42f861855b2 Tried writing to closed socket
06-4afe-a449-a42f861855b2 Tried writing to closed socket
06-4afe-a449-a42f861855b2 Tried writing to closed socket
06-4afe-a449-a42f861855b2 Tried writing to closed socket
06-4afe-a449-a42f861855b2 Tried writing to closed socket
06-4afe-a449-a42f861855b2 Tried writing to closed socket
06-4afe-a449-a42f861855b2 Tried writing to closed socket
06-4afe-a449-a42f861855b2 Tried writing to closed socket
06-4afe-a449-a42f861855b2 Tried writing to closed socket
41-4385-9762-c5c1d829ba27 Tried writing to closed socket
0f-4eb4-9751-b5ac7e21c648 Tried writing to closed socket
06-4afe-a449-a42f861855b2 Tried writing to closed socket
06-4afe-a449-a42f861855b2 Tried writing to closed socket
60-40d1-99b4-349f03610b36 Tried writing to closed socket
60-40d1-99b4-349f03610b36 Tried writing to closed socket
33-414d-9143-6a5080bd6254 Tried writing to closed socket
06-4afe-a449-a42f861855b2 Tried writing to closed socket 

Code from Mastodon main

  const streamToWs = (req, ws, streamName) => (event, payload) => {
    if (ws.readyState !== ws.OPEN) {
      log.error(req.requestId, 'Tried writing to closed socket');
      return;
    }

Found in mastodon/streaming/index.js

Logs (correlation) from mastodon-web on Fritz

This is where we are suspecting that we are hitting the “Rack Attack” rate limit in the streaming service.

-4589-97ed-b67c66eb8c38] Rate limit hit (throttle): 98.114.90.221 GET /api/v1/timelines/home?since_id=109>

Working Theory (root cause)

We are maxing out the streaming service on Fritz, and it is rate limiting the mastodon web (puma) service. The “maxing out” can be described in the write-up by @ThisIsMissEm where NodeJS struggles to process/drop the connections that are potentially a result of a “Large Event”.

As the websocket count increases there is a cascading failure that starts on Fritz and works it way out to the nodes.

Eventually the code that is executing (looping) over the large amounts of websockets will “break” and there is a large release where a spike in network traffic can be observed.

We see an enormous (relatively) amount of events occur during the second of 22:17:30 on Fritz which we suspect is the “release” of the execution path.

As the streaming service recovers, the rest of Hachyderm slowly stabilizes.

Lessons Learned

Websockets are a big deal, and will likely be the next area of our service we need to start observing.

We will need to start monitoring the relationship between the streaming service and the main mastodon web service pretty closely.

Things that went well

We found some great help on Twitch, and we ended up discovering an unrelated (but potentially disastrous) problem with Nietzsche (the main database server).

We have a path forward for debugging the streaming issues.

Things that went poorly

Nóva was short on Twitch again and struggles to deal with a lot of “noise/distractions” while she is debugging production.

In general there isn’t much more we can do operationally other than keep a closer eye on things. The code base is gonna’ do what the code base is gonna’ do until we decide to fork it or wait for improvements from the community.

Where we got lucky

Seriously the Nietzsche discovery was huge, and had nothing to do with the streaming “hiccups”. We got extremely lucky here.

Consequently, Nóva fixed the problem on Nietzsche which was that our main database NVMe disk was at 98% capacity.

• We did NOT receive storage alerts in Discord (I believe we should have?)
• Nóva could NOT find an existing cron job on the server to clean the archive.
• Nóva scheduled the cron job (Using sudo crontab -e)

The directory (archive) that was full:

/var/lib/postgres/data/archive

Nietzsche is now back down to ~30%

Action items

1) Set up websocket observability on CDN nodes (clients) and Fritz (server)

We want to see how many “writes” we have on the client side and how many socket connections they are mapped to if possible. We might need to PR a log entry for this to the Mastodon code base.

2) Verify cron is running on Nietzsche

We need to make sure the cron is running and the archive is emptying

3) Debug why we didn’t receive Nietzsche alerts

I think we should have seen these, but I am not sure?

4) We likely need a bigger “Fritz”

Sounds like we need donations and a bigger server (it will be hard to move streaming off of the same machine as web).

Fritz on the fritz

On January 3th, 2023 at approximately 12:30 UTC Hachyderm experienced a spike in response times. This appeared to be due to a certificate that had not been renewed on fritz, which runs the Mastodon Puma and Streaming services. The service appeared to recover until approximately 15:00 UTC when another spike in response times was observed.

Alerts were firing in discord alerting us to the issue.

Background

fritz runs mastodon-web and mastodon-streaming and all other web nodes proxy to fritz.

mastodon-web was configured with 16 processes each having 20 threads.

mastodon-streaming was configured with 16 processes

Impact

p90 response times grew from ~400ms to >2s. increase of 502 responses to >1000 per minute.

Root causes and trigger

organic growth in users and traffic coupled with the return from vacation of the US caused the streaming and puma processes on fritz to use more CPU. CPU load hit >90% consistently on fritz. this in turn caused responses to fail to be returned to the upstream web frontends.

Lessons Learned

response times are very sensitive to puma threads (reducing from 20 to 16 threads per process doubled GET response times).

the site functions well with fewer streaming processes.

Things that went well

we had the core CPU load on the public dashboard.

Things that went poorly

in an attempt to get things under control both mastodon-streaming and mastodon-web were changed. puma was then reverted as we had over-corrected and response times were getting quite bad.

no CPU load alerts were configured for fritz specifically.

Where we got lucky

@dma was already keyed in to fritz thanks to an earlier issue where certs hadn’t been renewed.

Action items

1) Streaming processes reduces @dma [repair]

Reduced the number of streaming processes on fritz from 16 to 12.

2) Better alerting on CPU load @dma [detect]

We should implement better CPU load alerting on every host to detect these issues and be able to respond even more quickly.

3) Postmortem documented @dma

This blog post and a hackmd postmortem doc.

The Queues ☃️ down in Queueville

Every Queue down in Queueville liked ActivityPub a lot. But John Mastodon who lived just north of Queuville, did not! John Mastodon hated ActivityPub, the whole Activity season! Now please don’t ask why. No one quite knows the reason.

It could be, perhaps, that his WEB_CONCURRENCY was too tight. It could be his MAX_THREADS wasn’t screwed on just right. But I think that the most likely reason of all May have been that his CPU was two sizes too small.

But, whatever the reason, his WEB_CONCURRENCY or CPUs, He stood there on Activity Eve hating the Queues… Staring down from his cave with systemd hacks At the warm buzzing servers below in their racks

For he knew every Queue down in Queueville beneath Was busy now hanging an Activity-Wreath. “And they’re posting their statuses,” he snarled with a sneer. “Tomorrow is Activity-Mas! It’s practically here!”

Then he growled, with John Mastodon fingers nervously drumming, “I must find some way to keep the statuses from coming”!

For, tomorrow, I know all the Queues and the “they"s and the “them"s Will wake bright and early for ActivitySeason to begin!

And then! Oh, the noise! Oh, the noise! Noise! Noise! Noise! There’s one thing John Mastodon hates: All the NOISE! NOISE! NOISE! NOISE!

And they’ll shriek squeaks and squeals, racing ‘round on their hosts. They’ll update with jingtinglers tied onto their posts! They’ll toot their floofloovers. They’ll tag their tartookas. They’ll share their whohoopers. They’ll follow their #caturday-ookas. They’ll spin their #hashtags. They’ll boost their slooslunkas. They’ll defederate their blumbloopas. But complain about their whowonkas.

And they’ll play noisy games like post a cat on #caturday, An ActivityPub type of all the queers and the gays! And then they’ll make ear-splitting noises galooks On their great big postgres whocarnio ruby monolith flooks!

Then the Queues, young and old, will sit down to a feast. And they’ll feast! And they’ll feast! And they’ll FEAST! FEAST! FEAST! FEAST!

They’ll feast on Queue-pudding, and rare Queue-roast-beast, Ingress Queue roast beast is a feast I can’t stand in the least!

And then they’ll do something I hate most of all! Every Queue down in Queueville, the tall and the small,

They’ll stand close together, with UptimeRobot bells ringing. They’ll stand hand-in-hand, and those Queues will start singing!

And they’ll sing! And they’ll sing! And they’d SING! SING! SING! SING! And the more John Mastodon thought of this Queue Activity Sing, The more John Mastodon thought, “I must stop this whole thing!”

Why for fifty-three days I’ve put up with it now! I must stop ActivityPub from coming! But how?

Timeline

All events are documented in UTC time.

• 13:00 @dma Noticed the ingress queue was backing up
• 16:45 @quintessence Noticed the ingress queue was still lagging
• 17:00 @nova Declared an incident
• 17:30 @hazelweakly Noticed CPU at 100% on Freud and Franz
• 17:34 @hazelweakly Worked with @dma to rebalance queues across Freud, Franz, and Nietzsche
• 17:37 @dma Notices CPU on Nietzsche is not changing
• 17:45 @hazelweakly Changes 5 MAX_THREADS to 20 MAX_THREADS on Nietzsche

ActivityEve

“I know just what to do!” John Mastodon laughed in his throat. “I’ll max out the CPU, and cause the network to bloat.”

And he chuckled, and clucked, “What a great John Mastodon trick! With this CPU and network lag, I’ll cause the latency to stick!”

“All I need is a denial of service.” John Mastodon looked around. But since denial of services are scarce, there was none to be found.

Did that stop John Mastodon? Hah! John Mastodon simply said, “If I can’t find a denial of service, I’ll make one instead!”

So he took his dog MAX, and he took some more EMPTY_THREADS. And he tied big WEB_CONCURRENCY on top of his head. Then he loaded some cores and some old empty racks. On a ramshackle sleigh and he whistled for MAX.

Then John Mastodon said “Giddyap!” and the sleigh started down Toward the homes where the Queues lay a-snooze in their town.

All their graphs were dark. No one knew he was there. All the Queues were all dreaming sweet dreams without care. When he came to the first little house of the square.

“This is stop number one,” John Mastodon hissed, As he climbed up load average, empty cores in his fist.

Then he slid down the ingress, a rather tight bond. But if a denial of service could do it, then so could John Mastodon.

The queues drained only once, for a minute or two. Then he stuck his posts out in front of the ingress queue!

Where the little Queue messages hung all in a row. “These messages,” he grinched, “are the first things to go!”

Then he slithered and slunk, with a smile most unpleasant, Around the whole server, and he took every message!

Cat pics, and updates, artwork, and birdsite plea’s! Holiday cheer, Hanukkah, Kwanza and holiday trees!

And he stuffed them in memory. John Mastodon very nimbly, Stuffed all the posts, one by one, up the chimney.

Then he slunk to the default queues. He took the queues’ feast! He took the queue pudding! He took the roast beast!

He cleaned out that /inbox as quick as a flash. Why, John Mastodon even took the last can of queue hash!

Then he stuffed all the queues up the chimney with glee. “Now,” grinned John Mastodon, “I will stuff up the whole process tree!”

As John Mastodon took the process tree, as he started to shove, He heard a small sound like the coo of a dove…

He turned around fast, and he saw a small Queue! Little Cindy-Lou Queue, who was no more than two.

She stared at John Mastodon and said, “our statuses, why? Why are you filling our queues? Why?”

But, you know, John Mastodon was so smart and so slick, He thought up a lie, and he thought it up quick!

“Why, my sweet little tot,” John Mastodon lied, “There’s a status on this /inbox that won’t light on one side.

So I’m taking it home to my workshop, my dear. I’ll fix it up there, then I’ll bring it back here.”

And his fib fooled the child. Then he patted her head, And he got her a drink, and he sent her to bed.

And when Cindy-Lou Queue was in bed with her cup, He crupt to the chimney and stuffed the ingress queues up!

Then he went up the chimney himself, the old liar. And the last thing he took was /var/log for their fire. On their .bash_history he left nothing but hooks and some wire.

And the one speck of content that he left in the house Was a crumb that was even too small for a mouse.

Then he did the same thing to the other Queues’ houses, Leaving crumbs much too small for the other Queues’ mouses!

Timeline

All events are documented in UTC time.

• 17:58 @dma Notices we are no longer bottlenecked on Ingress after @hazelweakly makes changes
• 18:03 @dma Provides update on priority of systemd flags
• 18:10 @dma Provides spreadsheet for us to calculate connections to database

ActivityMorn

It was quarter of dawn. All the Queues still a-bed, All the Queues still a-snooze, when he packed up his sled,

Packed it up with their statuses, their posts, their wrappings, Their posts and their hashtags, their trendings and trappings!

Ten thousand feet up, up the side of Mount Crumpet, He rode with his load average to the tiptop to dump it!

“Pooh-pooh to the Queues!” he was John Msatodon humming. “They’re finding out now that no ActivityPub messages are coming!

They’re just waking up! I know just what they’ll do! Their mouths will hang open a minute or two Then the Queues down in Queueville will all cry boo-hoo!

That’s a noise,” grinned John Mastodon, “that I simply must hear!” He paused, and John Mastodon put a hand to his ear.

And he did hear a sound rising over the snow. It started in low, then it started to grow.

But this sound wasn’t sad! Why, this sound sounded glad!

Every Queue down in Queueville, the tall and the small, Was singing without any ActivityPub messages at all!

He hadn’t stopped ActivityPub messages from coming! They came! Somehow or other, they came just the same!

And John Mastodon, with his feet ice-cold in the snow, Stood puzzling and puzzling. “How could it be so?”

Posts came without #hashtags! It came without tags! It came without content warnings or bags!

He puzzled and puzzled till his puzzler was sore. Then John Mastodon thought of something he hadn’t before.

Maybe ActivityPub, he thought, doesn’t come from a database store. Maybe ActivityPub, perhaps, means a little bit more!

And what happened then? Well, in Queueville they say That John Mastodon’s small heart grew three sizes that day!

And then the true meaning of ActivityPub came through, And John Mastodon found the strength of ten John Mastodon’s, plus two!

And now that his heart didn’t feel quite so tight, He whizzed with his load average through the bright morning light!

With a smile to his soul, he descended Mount Crumpet Cheerily blowing “Queue! Queue!” aloud on his trumpet.

He road into Queuville. He brought back their joys. He brought back their #caturday images to the Queue girls and boys!

He brought back their status and their pictures and tags, Brought back their posts, their content and #hashtags.

He brought everything back, all the CPU for the feast! And he, he himself, John Mastodon carved the roast beast!

Welcome ActivityPub. Bring your cheer, Cheer to all Queues, far and near.

ActivityDay is in our grasp So long as we have friends’ statuses to grasp.

ActivityDay will always be Just as long as we have we.

Welcome ActivityPub while we stand Heart to heart and hand in hand.

Timeline

All events are documented in UTC time.

• 18:10 @hazelweakly Provides update that queues are now balancing and load is coming down
• 18:18 @nova Confirms queues are draining and systems are stabilizing

Root Cause

John Mastodon took the queue hash, and up the chimney he stuck it. The Hachyderm crew was too tired to fill out the report and said “fuck it”.

Nietzsche:
- 4 default queues (unchanged)
- 32 default ingress (changed)

Franz:
- 6 default queues (unchanged)
- 1 ingress queue (changed)
- 5 pull queues (unchanged)
- 5 push queues (unchanged)

Freud:
- 3 default queues (unchanged)
- 2 ingress queues (changed)
- 2 pull queue (changed)
- 2 push queue (changed)

Changes:

Because the database connection count per ingress queue process changed, when necessary, I will clarify queue amounts in terms of database connections.

- Moved 2 ingress queues (40 DB connections) from franz to nietzsche
- Moved 2 ingress queues (40 DB connections) from freud to nietzsche
- Changed DB_POOL on ingress queues from 20 to 5 as they're heavily CPU bound.
- Changed -c 20 on ingress queues from 20 to 5 as they're heavily CPU bound.
- Scaled Nietzsche up from 8 ingress queues to 32 to keep the amount of total database connections the same.
- Restarted the one ingress queue remaining on franz (this lowered ingress DB connections from 20 to 5).
- Restarted the two ingress queues remaining on freud (this lowered ingress DB connections from 40 to 10).
- Removed a "pushpull" systemd service on Freud and replaced it with independent push and pull sidekiq processes (neutral db connection change).

Degraded Service: Media Caching and Queue Latency

On Saturday, December 17th, 2022 at roughly 12:43 UTC Hachyderm received our first report of media failures which started a 2-day-long investigation of our systems by @hazelweakly, @quintessence, @dma, and @nova. The investigation coincidentally overlapped with a well-anticipated spike in growth which also unexpectedly degraded our systems simultaneously.

The first degradation was unplanned media failures, typically in the form of avatar and profile icons intermittently on the service. We had an increase in 4XX level responses due to misconfigured cache settings in our CDN. We believe the Western US to be the only region impacted by this degradation.

The second degradation was unplanned queue latency increasing presumably from the increase in usage due to the fallout of Twitter mass exodus. We experienced an increase in our push and pull queues, as well as a short period of default latency.

Timeline

All events are documented in UTC time.

• Dec 16th 12:43 @arjenpdevries First report of media cache misses #217
• Dec 17th 08:21 @blueturtleai 2nd Report, and first confirmation of media cache misses #218
• Dec 17th 21:43 @quintessence 3rd Report of media cache misses
• Dec 17th 21:44 @nova False mediation of cmd+shift+r cache refresh
• Dec 17th 22:XX More reports of cache failures, multiple Discord channels, and posts
• Dec 17th 23:XX More reports of cache failures, multiple Discord channels, and posts
• Dec 17th 24:XX Still assuming “cache problems” will just fix themselves
• Dec 18th 14:45 @dma Nginx audit and location{} rewrite on fritz; no results
• Dec 18th 14:45 @dma No success debugging various CDN nodes and cache strategies
• Dec 18th 15:16 @dma Check mastodon-web logs on CDNs; /system GETs with 404s
• Dec 18th 20:32 @hazelweakly Discovered .env.production misconfiguration cdn-frankfurt-1, franz
• Dec 18th 20:41 @quintessence Confirms queues are backing up

• Dec 18th 20:45 @hazelweakly Confirms actively reloading services to drain queues
• Dec 18th 21:17 @malte_j Appears from vacation, and is told to go back to relaxing
• Dec 18th 21:23 @hazelweakly Continues to “tweak and tune” the queues
• Dec 18th 21:32 @hazelweakly Claims we are growing at <1 user per minute
• Dec 18th 21:45 @dma Reminder to only focus on ingress and default queues
• Dec 18th 21:47 @hazelweakly Identifies queue priority fix using systemd units
• Dec 18th 21:47 @hazelweakly Suggests moving queues to CDN nodes
• Dec 18th 21:59 @dma Suggests migrating DB from freud -> nietzsche
• Dec 18th 22:15 @hazelweakly Summary confirms sidekiq running on CDNs
• Dec 18th 22:18 @nova Identifies conversation in Discord, and begins report

Root Cause

The cause of the caching 4XX responses and broken avatars was a misconfigured .env.production file on cdn-fremont-1 and franz.

S3_ENABLED=FALSE # Should be true
3_BUCKET=".."    # Should be S3_BUCKET

The cause of the queue latency is suspected to be the increase in usage from Twitter, as well as the queue priority documented here in the official Mastodon scaling up documentation.

ExecStart=/usr/bin/bundle exec sidekiq -c 10 -q default

Things that went well

We have the cache media fixed, and we have been alerted to a high-risk concern early giving the team enough time to respond.

Things that went poorly

An outage was never declared for this incident, and therefore it was not handled as well as it could have been. Various members of the team were mutating production with reckless working habits

• Documenting informally in private infrastructure GitHub repository
• Discord used as documentation
• No documenting just “tinkering” alone
• Documenting after the fact
• Not using descriptive language, EG: “Tweaked the CDNs” instead of changed on from to .

Unknown state of production after the incident. Unsure which services are running where, and who has what expectations for which services.

The configuration roll-out obviously had failed at some point, indicating a stronger need for config management on our servers.

We seemed to lose track of where the incident started and stopped and where improvements and action items began. For some reason we decided to make suggestions about next steps before we were entirely sure on the state of the systems today, and having a plan in place.

Opportunities

Config management should be a top priority.

Auditing and migrating sidekiq services off of CDN nodes should be a top priority.

Migrating the database from freud -> nietzsche should be a priority.

We shouldn’t be planning or discussing future improvements until the systems are restored to stability. Incidents are not also a venue for decision-making.

Resulting Action

1) Plan for Postgres migration

@nova and @hazelweakly planning live stream to migrate production database and clear up more compute power for sidekiq queues

2) TODO Configuration Management

We need to identify a configuration management pattern for our systems sooner than later. Perhaps an opportunity for a new volunteer.

3) TODO Discord Bot Incident Command

We need to identify ways of managing and starting and stopping incidents using Discord. Maybe in the future we can have “live operating room” incidents where folks can watch read-only during the action.

Global Outage: 504 Timeouts

On Tuesday, December 13th, 2022 at roughly 18:52 UTC Hachyderm experienced a 7 minute cascading failure that has impacted our users around the globe resulting in unresponsive HTTP(s) requests and 5XX level requests. The service has not experienced any data loss. We believe this was a total service outage.

Impacted users experienced 504 timeout responses from https://hachyderm.io in all regions of the world.

Timeline

All events are documented in UTC time.

• 18:53 @nova First report of slow response times in Discord
• 18:55 @dma First confirmation, and first report of 5XX responses globally
• 18:56 @dma Check of Mastodon web services, no immediate concerns
• 18:56 @nova Check of CDN proxy services, no immediate concerns
• 18:57 @nova First observed 504 timeout
• 18:58 @dma status.hachyderm.io updated acknowledging the outage
• 18:59 @nova First observed redis error, unable to persist to disk

Dec 13 18:59:01 fritz bundle[588687]: [2eae54f0-292d-488e-8fdd-5c35873676c0] Redis::CommandError (MISCONF Redis is configured to save RDB snapshots, but it's currently unable to persist to disk. Commands that may modify the data set are disabled, because this instance is configured to report errors during writes if RDB snapshotting fails (stop-writes-on-bgsave-error option). Please check the Redis logs for details about the RDB error.):

• 19:01 @UptimeRobot First alert received

Monitor is DOWN: hachyderm streaming 
( https://hachyderm.io/api/v1/streaming/health ) - Reason: HTTP 502 - Bad Gateway

• 19:02 @nova Root cause detected. The root filesystem is full on our primary database server.

• 19:04 @nova Identified postgres archive /var/lib/postgres/archive data exceeds 400Gb of history
• 19:05 @malte_j Request to destroy archive
• 19:06 @malte_j Confirmed archive has been destroyed
• 19:06 @malte_j Confirmed 187Gb of space has been recovered
• 19:06 @dma status.hachyderm.io updated acknowledging the root cause
• 19:07 @nova Begin drafting postmortem notes
• 19:16 @nova Official announcement posted to Hachyderm

Root Cause

Full root filesystem on primary database server resulted in a cascading failure that first impacted Redis’s ability to persist to disk which later resulted in 5XX responses on the edge.

Things that went well

We had a place to organize, and folks on standby to respond to the incident.

We were able to respond and recover in less than 10 minutes.

We were able to document and move forward in less than 60 minutes.

Things that went poorly

There was confusion about who had access to update status.hachyderm.io and this is still unclear.

There was confusion about where redis lived, and which systems where interdependent upon redis in the stack.

The Novix installer is still our largest problem and is responsible for a lot of confusion. We do not have a better way forward to manage packages and configs in production. We need to decide on Nix and our path forward as soon as possible.

Opportunities

We need to harden our credential management process, and account management. We need to have access to our systems.

We need global architecture, ideally observed from the systems themselves and not in a diagram.

When an announcement is resolved, it removes the status entirely from UptimeRobot. We can likely improve this.

Resulting Action

1) Cron cleanup scheduled @malte_j

Cron scheduled to remove postgres archive greater than 5 days.

#!/bin/bash
set -e

cd /var/lib/postgres/data/archive
find * -type f -mtime 5 -print0 | sort -z | tail -z -n 1 | xargs -r0 pg_archivecleanup /var/lib/postgres/data/archive

2) Alerts configured @dma

Alerts scheduled for >90% filesystem storage on database nodes.

Postmortem template created for future incidents.

3) Postmortem documented @nova

This blog post as well as a small discussion in Discord.