jakman85
e8d8601ca6
`instances: 3` alone does not keep the three instances apart. All three Clusters used CNPG's default `podAntiAffinityType: preferred`, which is a scheduler HINT — two instances may share a node whenever that scores better, and they WILL on the path that matters: when CNPG recreates an instance after a node loss, the surviving nodes are the only candidates and one of them already runs an instance. `preferred` is how a 3-instance cluster decays back into the single-node failure domain the previous commit exists to remove. `required` makes it a scheduling constraint. On a 3-node cluster with no spare, the cost is that an instance whose node is gone stays Pending until a node returns. That is correct: a replacement squeezed onto an already-occupied node dies with that node while making the cluster LOOK three-way replicated. 2 of 3 instances still serve and CNPG still promotes. ALSO SETS primaryUpdateMethod: switchover. This is not cosmetic. Changing the affinity changes the instance pod spec, so CNPG performs a rolling update, and the CRD default for primaryUpdateMethod is `restart` (verified against the live CNPG 1.30.0 CRD on both clusters) — a delete-and-recreate of the PRIMARY pod, i.e. tens of seconds of no Postgres. On keycloak-db that is an SSO outage, which also means kubectl OIDC, Grafana, Headlamp, Gitea and forward-auth. With standbys now present, `switchover` promotes an already-updated streaming replica instead, reducing the roll to a connection reset. Known constraint documented in the manifest: under `switchover` the operator rejects an update that changes imageName and a postgresql parameter in the same reconcile. Verified satisfiable before merge (read-only): k3s-prod and k3s-dev each have 3 Ready, schedulable, untainted nodes, and every pgdata PVC already has a Longhorn replica on all three (replica-soft-anti-affinity=false), so any instance can attach from any node. DEV IMPACT: identical, and dev can absorb it. Longhorn dev nodes are 124.9 GiB each with 152.0 GiB already scheduled under a 200% over-provisioning ceiling (249.8 GiB); the six new 5Gi volumes add 30 GiB scheduled per node -> 182.0, still inside the ceiling, and only ~600 MiB per volume is really consumed. Prod is far looser: 239 -> 269 GiB scheduled against a 829 GiB ceiling. THIS IS THE DISRUPTIVE COMMIT of the three. Land it on its own reconcile, after the scale-out has produced two Ready standbys per Cluster, so the blast radius is one clean switchover per database rather than a scale-out and a roll at once. Expect a brief SSO interruption for keycloak-db. Verified: yamllint clean; both tiers render the new fields; field names, types and enum values checked against the live clusters.postgresql.cnpg.io CRD (CNPG 1.30.0, identical on prod and dev). Co-Authored-By: Claude Opus 5 <[email protected]> (cherry picked from commit e1d364238d73e6ee99c9a50108fe8b4e09481a7e)