A wild first month: Scaling a 25,000 user Mastodon instance on Kubernetes

When the Twitter exodus began, I jumped at the chance to host my own Mastodon instance, toot.community. This post recounts the wild first month of rapidly scaling from 60 to over 25,000 users using Kubernetes, the challenges faced, and how we open-sourced the setup.

It’s hard to believe it's already been a full month since I jumped into the world of Mastodon server administration. Like many tech enthusiasts, I was intrigued when Elon's Twitter purchase sparked a massive search for alternatives. Mastodon, with its decentralized promise – anyone and no one owning the platform – felt like the future.

Loving a technical challenge, I decided to spin up my own instance. What I didn't fully anticipate was the sheer speed of the exodus. The first week was... intense. If memory serves, the user count went something like this:

  • November 4th: 60 users
  • November 5th: 600 users
  • November 6th: 6,000 users
  • November 7th: 15,000 users

Things grew like crazy. By the 7th, it really felt like all hands on deck. Thankfully, with my day job revolving around Kubernetes, I'd decided from day one to build the Mastodon infrastructure using it. That decision likely saved the instance, but it didn't mean smooth sailing. Much of that first week was a blur of scrambling for bigger database servers, beefier node pools, and optimizing everything on the fly.

It quickly became clear this was too much for one person juggling a day job. I called in my good friend Mijndert Stuij – between us, we have over 25 years of experience managing online software at scale, and his help was invaluable.

As things started stabilizing, we knew we wanted to share what we'd learned and built for my instance, toot.community. Mijndert meticulously translated our infrastructure setup into Terraform, while I focused on cleaning up the Kubernetes manifests to make them easily shareable.

Now, after a full month of refining, testing, and documenting, I'm thrilled to say our infrastructure and configuration are open-sourced and ready for the world:

We've also written a more detailed post about the open-sourcing journey over on the instance blog: blog.toot.community/posts/open-sourcing-toot-community/

It's been a wild, sometimes stressful, but ultimately rewarding first month. Running a large Mastodon instance on Kubernetes is definitely feasible, and hopefully, sharing our setup helps others navigate their own scaling adventures.