PostgreSQL in minikube

postgres-in-minikube.sh

# create/update resources
kubectl --context=minikube apply -f ./postgres.yaml

# In order for the service to reach the statefulset, the following should
# be true:
#   statefulset.spec.selector.matchLabels.app  == service.spec.selector.app
#   statefulset.spec.selector.matchLabels.role == service.spec.selector.role

# give the server some time to start up
# ...

# test the connection from outside the cluster
psql --host=$(minikube ip) \
     --port=$(minikube service postgres --url --format={{.Port}}) \
     --username=postgres \
     --dbname=postgres

# test the connection from within the cluster
url=$(kubectl --context=minikube get service postgres \
              --output=jsonpath='{.spec.clusterIP}:{.spec.ports[0].port}')
kubectl --context=minikube run pgbox --image=postgres:9.6 \
    --rm -it --restart=Never -- \
    bash -c "read &&
             psql --host=${url%:*} --port=${url#*:} \
                  --username=postgres --dbname=postgres \
                  --command='SELECT refobjid FROM pg_depend LIMIT 1'"

# remove resources
kubectl --context=minikube delete -f ./postgres.yaml --ignore-not-found
# Data will survive the above operation, and be available next time you revive postgres.

postgres.yaml

apiVersion: v1
kind: PersistentVolume
metadata:
  name: postgres
spec:
  accessModes:
    - ReadWriteOnce
  capacity:
    storage: 2Gi
  hostPath:
    path: /data/postgres
  storageClassName: standard
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: postgres
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 2Gi
  volumeName: postgres
---
apiVersion: v1
kind: Secret
metadata:
  name: postgres
type: Opaque
data:
  POSTGRES_USER: cG9zdGdyZXM=     # printf postgres | base64
  POSTGRES_PASSWORD: cGFzc3dvcmQ= # printf password | base64
---
apiVersion: apps/v1beta2
kind: StatefulSet
metadata:
  name: postgres
  labels:
    app: postgres
    role: service
spec:
  replicas: 1
  selector:
    matchLabels:
      app: postgres
      role: service
  serviceName: postgres
  template:
    metadata:
      labels:
        app: postgres
        role: service
    spec:
      containers:
        - name: postgres
          image: postgres:9.6
          env:
            - name: POSTGRES_USER
              valueFrom:
                secretKeyRef:
                  key: POSTGRES_USER
                  name: postgres
            - name: POSTGRES_PASSWORD
              valueFrom:
                secretKeyRef:
                  key: POSTGRES_PASSWORD
                  name: postgres
          ports:
            - containerPort: 5432
              name: postgres
              protocol: TCP
          volumeMounts:
            - name: postgres
              mountPath: /var/lib/postgresql/data
      volumes:
        - name: postgres
          persistentVolumeClaim:
            claimName: postgres
---
apiVersion: v1
kind: Service
metadata:
  name: postgres
  labels:
    app: postgres
    role: service
spec:
  selector:
    app: postgres
    role: service
  type: NodePort
  ports:
    - name: postgres
      port: 5432
      targetPort: 5432
      protocol: TCP