homelab/k8s-ng/core/postgresql/cluster.yaml

# Main HA PostgreSQL cluster: one primary and one streaming replica, each on its
# own node with a node-local volume. Replication is asynchronous (nodes sit in
# different regions), so a failover can lose the last few transactions.
#
# Layout: the primary runs on the music node (the powerful one), the replica on
# master. A failover swaps the roles; switch back with
#   kubectl cnpg promote main <instance on music>
#
# Nodes eligible for instances carry the label workload/postgres=true. To move a
# replica: label the new node, unlabel the old one, then recreate the instance
# (kubectl cnpg destroy main <N>); the operator re-clones it from the primary.
#
# Endpoints inside the cluster: main-rw (primary), main-ro (replicas),
# main-r (any instance) in the psql namespace.
apiVersion: postgresql.cnpg.io/v1
kind: Cluster
metadata:
  name: main
  namespace: psql
spec:
  description: Main HA PostgreSQL cluster
  imageName: ghcr.io/cloudnative-pg/postgresql:17
  instances: 2
  enableSuperuserAccess: false

  # Roll updates replica-first and hand over by switchover instead of restarting the primary.
  primaryUpdateStrategy: unsupervised
  primaryUpdateMethod: switchover

  storage:
    storageClass: local-path
    size: 20Gi # local-path volumes cannot be expanded later

  affinity:
    enablePodAntiAffinity: true
    podAntiAffinityType: required
    topologyKey: kubernetes.io/hostname
    nodeSelector:
      workload/postgres: "true"

  resources:
    requests:
      cpu: 500m
      memory: 1Gi
    limits:
      memory: 2Gi

  postgresql:
    parameters:
      max_connections: "200"
      shared_buffers: 512MB
      effective_cache_size: 1536MB