The first install-test run failed with both containers crash-looping
during boot:
system temporary path is world-writable: /tmp
/tmp is world-writable: /tmp
. is not writable: /rails
ArgumentError: could not find a temporary directory
raised from MiniMagick, which Active Storage loads while Rails boots.
Ruby's Dir.tmpdir skips a candidate that is world-writable without a
sticky bit, and a Kubernetes emptyDir is created mode 0777 with no sticky
bit - so with a read-only root filesystem there was no candidate left.
A tiny init container, the app's own image running as the same non-root
uid and with no capability added, now creates one private subdirectory
(mode 0700) inside each tmp emptyDir, and both containers run with
TMPDIR pointing at it. Creating an entry in a 0777 directory and chmod'ing
what one just created needs no privilege, so the hardening standard holds
unchanged.
One StatefulSet with two containers - the Puma web process and a Sidekiq
worker - sharing one ReadWriteOnce PVC at /rails/storage. That shared
volume is the reason they live in one pod: splitting them would need an
RWX volume. Only the web container migrates, because the image entrypoint
runs db:prepare solely for the './bin/rails server' command; the worker is
started through args: so the entrypoint (and its jemalloc preload) stays
in place and the two can never race.
Probes are chosen for what they prove: liveness and startup use Rails'
/up, which is a boot check and touches no database, while readiness uses
'/', which runs User.count through authenticate_user! in self-hosted mode
and therefore fails while Postgres is unreachable. The worker speaks no
HTTP, so all three of its probes ask sidekiqmon whether this pod still
holds a Sidekiq heartbeat in Redis.
Three OnePasswordItem CRs (app, database, redis), ingress.domain kept
required outside the Ingress because APP_DOMAIN and the WebAuthn relying
party read it, strict values.schema.json, CI fixtures with throwaway
Postgres 16 and Redis, and a Renovate manager on semver so the
-alpha/-rc/-hotfix channel and the moving tags are never selected.
jklein