“The migration from etcd to one-big-table in SQLite was easy.”
Tailscale outgrew etcd and moved its control plane back to a single file on disk. SQLite plus Litestream streaming the WAL to S3. They passed on Postgres and MySQL because nobody wanted to babysit replication. The pain wasn’t SQLite. It was their own etcd caching layer and migration tooling they had to write by hand.