Mastodon is a federated microblog server: local timelines plus ActivityPub links to other instances. Running it means managing state (PostgreSQL, media, cache) and edge (HTTPS and /.well-known for discovery). The lab instance is at https://mastodon.this-is-fine.social.

It ships as a Helm release through Flux, same GitOps style as the rest of the lab.

Federation is the interesting part socially and technically. Other servers discover you through HTTPS hostnames and /.well-known endpoints; if DNS or TLS drifts, federation breaks even when the pod is healthy. That is why the lab treats edge (Gateway API, cert-manager, external-dns) as first-class dependencies, not an afterthought.