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.
Software map
| Need | Project | Learn |
|---|---|---|
| App | Mastodon | Admin setup |
| SQL | CloudNative-PG | Postgres operator |
| Cache | Dragonfly | Redis-compatible cache |
| Media | Rook-Ceph RGW | S3 API via ObjectBucketClaim |
| Ingress | Gateway API | HTTPRoute on shared-gateway-external |
| TLS | cert-manager | ACME for *.this-is-fine.social |
| Secrets | External Secrets | SMTP, VAPID, secretKeyBase from Vault |
Request path
Internet
-> mastodon.this-is-fine.social (HTTPRoute)
-> Mastodon (Helm)
PostgreSQL (CNPG)
Dragonfly (cache)
object storage (Rook S3)
Federation needs stable DNS and valid TLS — see Mastodon
federation notes. SMTP, VAPID, and
secretKeyBase sync from Vault through External Secrets, like other lab apps.
Media attachments land in object storage (Rook’s S3-compatible endpoint) so the web pods do not fill local disks with uploads. PostgreSQL holds accounts and timelines; Dragonfly backs Redis-shaped caching Mastodon expects. None of those pieces are optional if you want a instance that survives real use.
Capacity and backups
Mastodon is not a small Deployment: size CPU, memory, and database disk from upstream guidance. Database backups (CNPG) and optional PVC backups (VolSync) are separate choices.
Other fediverse apps (for example Pixelfed) can share the namespace; this article stays on Mastodon.
Further reading: ActivityPub, Mastodon releases.