feat(cnpg): enable quorum commit on the real database clusters (#613)

charts/platform/cnpg-cluster/templates/cluster.yaml

@@ -11,6 +11,10 @@ spec:
   {{- with .Values.affinity }}
   affinity: {{- toYaml . | nindent 4 }}
   {{- end }}
+  {{- with .Values.synchronous }}
+  postgresql:
+    synchronous: {{- toYaml . | nindent 6 }}
+  {{- end }}
   storage:
     size: {{ .Values.storage }}
     {{- with .Values.storageClass }}

charts/platform/cnpg-cluster/values.yaml

@@ -17,6 +17,8 @@ resources: {}
 # default "preferred" can co-schedule two instances, and local PVs
 # (WaitForFirstConsumer) then pin that co-location permanently.
 affinity: {}
+# CNPG spec.postgresql.synchronous. Empty = async, the CNPG default.
+synchronous: {}
 # Barman Cloud plugin backups (WAL archiving + daily base backup) to an
 # S3-compatible object store. Requires the plugin-barman-cloud release in
 # cnpg-system, so dev (no cert-manager, no plugin) keeps this off.

kubernetes/apps/base/yucca-database/helmrelease.yaml

@@ -32,6 +32,15 @@ spec:
     # (WaitForFirstConsumer) then pin that co-location permanently.
     affinity:
       podAntiAffinityType: required
+    # Quorum commit, so a lost primary can't take recent commits with it and
+    # leave the DB and the object store diverged. "preferred", not "required":
+    # instances sit on node-local PVs, so a dead node strands one until a human
+    # replaces it, and "required" would make that a write outage.
+    synchronous:
+      method: any
+      number: 1
+      failoverQuorum: true
+      dataDurability: preferred
     # Generous requests, huge memory limit (no CPU limit — CFS throttling hurts
     # postgres tail latency more than contention does).
     resources: