k3s-cluster/kubernetes/main/apps/database/postgresql/cert.yaml

apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: postgres-cert
  namespace: database
spec:
  secretName: postgres-cert

  duration: 2160h # 90d
  renewBefore: 360h # 15d

  issuerRef:
    name: ca-issuer
    kind: ClusterIssuer

  dnsNames:
  - postgresql.database