Anubis pre-2026-05-16 ran at replicas=1 because in-flight PoW challenge
state lived in process memory — a challenge issued by pod A wouldn't be
verifiable by pod B (HTTP 500 "store: key not found"). The PDB at
`minAvailable=1` made this worse: with replicas=1 the eviction API can
NEVER satisfy the constraint, so every drain on a node hosting an Anubis
pod looped forever. This is what stalled the manual K8s upgrade on
2026-05-11 (had to delete pods directly to bypass eviction) and was
about to block kured on Monday 2026-05-18 once the kured sentinel fix
landed.
Anubis upstream has first-class support for a Valkey/Redis-protocol
shared store (documented as the "Kubernetes worker pool" pattern).
Wire it up:
- modules/kubernetes/anubis_instance: add `shared_store_url` variable.
When set, appends a `store: { backend: valkey, parameters: { url } }`
block to the rendered policy YAML and defaults replicas to 2 (capped
at 2). PDB switched from `minAvailable=1` to `maxUnavailable=1` so
drains can take down one pod at a time. topologySpreadConstraint
tightened to `DoNotSchedule` so the two replicas land on different
nodes — a single node loss never takes a whole Anubis instance down.
- All 8 call sites (cyberchef, jsoncrack, kms, homepage, blog,
travel_blog, real-estate-crawler, f1-stream) opted in. Each picks a
unique Redis DB index (5–12) on `redis-master.redis:6379`. Cluster
Redis already runs HA via Sentinel + haproxy, no new infra needed.
Verified: every Anubis Deployment now 2/2 Ready with pods on different
nodes; PDBs allow 1 disruption; Redis DBs 5,7,8,10 already populated
by live traffic post-apply; Palo Alto Networks scanner hit blog right
after apply and the challenge log shows the new state path.
Drain on any worker now succeeds without a `predrain_unstick` workaround
— eviction API is satisfied because at most one pod is unavailable at a
time, and the other replica keeps serving. Monday's kured reboot wave
should roll through cleanly.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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