python/django/python-guestbook/kubernetes-manifests/guestbook-app.migration.yaml

# This file creates a job that migrates the Postgres database. The job creates a
# pod from the specified Docker image, wait for the database to get ready, and
# run database migration once the Postgres database service is ready to receive
# connections.
apiVersion: batch/v1
kind: Job
metadata:
  name: python-guestbook-migration
spec:
  template:
    metadata:
      name: python-guestbook-migration
    spec:
      initContainers:
      # Wait for the database to get ready before doing migration
      - name: check-db-ready
        image: postgres
        command: ['sh', '-c',
          'until pg_isready -h python-guestbook-db -p 5432;
          do echo waiting for database; sleep 2; done;']
      containers:
      - name: python-guestbook-migration
        image: python-guestbook-frontend-django
        command: [ "/bin/sh", "-c", "python manage.py migrate" ]
        env:
        - name: DATABASE_NAME
          value: "postgres"
        - name: DATABASE_USER
          value: "postgres"
        - name: DATABASE_HOST
          value: "python-guestbook-db"
        - name: DATABASE_PORT
          value: "5432"
      restartPolicy: OnFailure