postgres.yaml

apiVersion: v1
kind: Service
metadata:
  name: myapp-svc
spec:
  selector:
    app: myapp
  ports:
  - protocol: TCP
    port: 5432
    #targetPort: 5432

---

apiVersion: v1
kind: Pod
metadata:
  name: myapp-pod
  labels:
    app: myapp
spec:
  containers:
  - name: myapp-container
    image: postgres
    # command: ['sh', '-c', 'echo The app is running! && sleep 3600']
    tty: true
    ports:
    - containerPort: 5432

---

apiVersion: batch/v1
kind: Job
metadata:
  name: db
spec:
  template:
    metadata:
      name: db
      annotations:
        pod.beta.kubernetes.io/init-containers: '[
          {
            "name": "init-myservice",
            "image": "busybox",
            "command": ["sh", "-c", "until nslookup myapp-svc; do echo waiting for myapp-svc; sleep 2; done;"]
          },
        ]'
    spec:
      containers:
      - name: db-init
        image: postgres
        command: ['sh', '-c']
        args: ['PGPASSWORD=postgres psql --command="create database test;" -h myapp-svc -U postgres-p 5432 postgres']
      restartPolicy: Never
        #initContainers:
        #- name: wait-db
        #  image: busybox
        #  command: ["sh", "-c", "until nslookup myapp-pod; do echo waiting for myapp-pod; sleep 2; done;"]
    #- name: init-mydb
    #image: busybox
    #command: ['sh', '-c', 'until nslookup mydb; do echo waiting for mydb; sleep 2; done;']