Under active autoscaling the chart previously omitted .spec.instances entirely,
letting the KEDA HPA own it via /scale. But CNPG defaults an absent
.spec.instances to 1, and its admission webhook rejects a Cluster where
maxSyncReplicas >= instances ("maxSyncReplicas must be lower than the number of
instances"). So a fresh database created with autoscaling.enabled: true AND
synchronous quorum (maxSyncReplicas >= 1) was rejected at admission before KEDA
could ever scale it to effectiveMin (= maxSyncReplicas+1) — the whole tenant
HelmRelease failed. The default maxSyncReplicas: 0 path was unaffected, which is
why it went unnoticed. Verified live: a rendered Cluster with maxSyncReplicas: 1
and an omitted instances is rejected by the dev-cluster webhook; with the seeded
floor it is admitted.
Render instances: effectiveMin under active autoscaling instead of omitting it,
so a fresh Cluster starts at a valid, quorum-satisfying count. Because the chart
emits the same constant floor on every reconcile, Helm's three-way merge is a
no-op on the field and never reverts KEDA's higher live value, so the HPA still
owns the runtime count. Update the enablement docs (a new DB can enable directly
even with synchronous replication; existing DBs above the floor rebase to it
unless the two-phase transition flow is used) and add render tests for the fresh
create + maxSyncReplicas>=1 case.
Addresses the fresh-create-with-quorum admission gap found in branch review.
Signed-off-by: Alexey Artamonov <aleksei.artamonov@aenix.io>
Alexey Artamonov
610bcb5df9