I’m testing out Postgres in my microk8s cluster with cloudnative-pq. The installation was smooth:

sudo microk8s enable community
microk8s enable cloudnative-pg

I added a database cluster with superuser postgres like this:

apiVersion: v1
kind: Namespace
metadata:
  name: postgresql

---
apiVersion: postgresql.cnpg.io/v1
kind: Cluster
metadata:
  name: cluster-example
  namespace: postgresql
spec:
  enableSuperuserAccess: true
  instances: 3
  storage:
    size: 1Gi

In order to expose the Postgres services, some patching is required as described in the docs.

With microk8s, the following resources needs to patched:

• configmap/nginx-ingress-tcp-microk8s-conf
• daemonset/nginx-ingress-microk8s-controller
• service/loadbalancer (if e.g. metallb is enabled)

I’m using Fluxcd in my cluster, hence I’d like to do this in my Kustomization:

patches:
  - patch: |-
      apiVersion: v1
      kind: ConfigMap
      metadata:
        name: nginx-ingress-tcp-microk8s-conf
        namespace: ingress
      data:
        "5432": "postgresql/cluster-example-rw:5432"

  - target:
      version: v1
      kind: DaemonSet
      name: nginx-ingress-microk8s-controller
      namespace: ingress
    patch: |-
      - op: add
        path: /spec/template/spec/containers/0/ports/-
        value:
          containerPort: 5432
          hostPort: 5432
          name: postgres
          protocol: TCP

  - target:
      version: v1
      kind: Service
      name: loadbalancer
      namespace: ingress
    patch: |-
      - op: add
        path: /spec/ports/-
        value:
          name: postgres
          protocol: TCP
          port: 5432
          targetPort: 5432

The above patches won’t work without having the yaml-files for the resources to patch. So I had to find out which resources microk8s enable ingress created in my cluster and generate yaml-files for each of them (13 resources).
E.g.

microk8s kubectl -n ingress get configmap nginx-ingress-tcp-microk8s-conf -o yaml

With my current solution, I have to maintain these yaml-files. Is there a simpler way to generate the yaml-files? I believe I’ve to do this again after chart upgrades.

I couldn’t find any microk8s command for this, but maybe there’s a generic k8s-solution for this?