Exercise

Create a file named wordpress_pod.yaml that specifies a Pod with the following characteristics:

name: wp
first container:
- named wordpress
- based on the image wordpress:4.9-apache
- defining the environment variable named WORDPRESS_DB_PASSWORD with the value mysqlpwd (see note below)
- defining the environment variable named WORDPRESS_DB_HOST with the value 127.0.0.1 (see note below)
a second container:
- named mysql
- based on the image mysql:5.7
- defining the environment variable named MYSQL_ROOT_PASSWORD with the value mysqlpwd (see note below)

note: to define environment variables for a Pod’s container’s specification, you can use the following format:

...
containers:
- name: CONTAINER_NAME
  image: CONTAINER_IMAGE
  env:
  - name: VARIABLE_NAME
    value: VARIABLE_VALUE

Run the Pod
Check the Pod’s status and get its IP address
Access the application using the port-forward subcommand
Delete the Pod

Solution

The Pod’s specification is the following one:

apiVersion: v1
kind: Pod
metadata:
  name: wp
spec:
  containers:
  - image: wordpress:4.9-apache
    name: wordpress
    env:
    - name: WORDPRESS_DB_PASSWORD
      value: mysqlpwd
    - name: WORDPRESS_DB_HOST
      value: 127.0.0.1
  - image: mysql:5.7
    name: mysql
    env:
    - name: MYSQL_ROOT_PASSWORD
      value: mysqlpwd

Note: the Pod’s specification can also include a volume to persist the data outside of the mysql container’s filesystem

apiVersion: v1
kind: Pod
metadata:
  name: wp
spec:
  containers:
  - image: wordpress:4.9-apache
    name: wordpress
    env:
    - name: WORDPRESS_DB_PASSWORD
      value: mysqlpwd
    - name: WORDPRESS_DB_HOST
      value: 127.0.0.1
  - image: mysql:5.7
    name: mysql
    env:
    - name: MYSQL_ROOT_PASSWORD
      value: mysqlpwd
    volumeMounts:
    - name: data
      mountPath: /var/lib/mysql
  volumes:
  - name: data
    emptyDir: {}

The Pod can be launched with the following command:

kubectl apply -f wordpress_pod.yaml

The following command gets the status of the wp Pod:

kubectl get po/wp

For a couple of seconds, the Pod will be in the ContainerCreating status (while the images are downloaded from the DockerHub):

NAME      READY     STATUS              RESTARTS   AGE
wp        0/2       ContainerCreating   0          49s

Then the Pod will appear in the Running status:

NAME      READY     STATUS    RESTARTS   AGE
wp        2/2       Running   0          2m

Run the following command to open a local port mapped to the Wordpress container’s port:

kubectl port-forward wp 8080:80

From your web browser, open the URL http://localhost:8080 to access the Wordpress interface.

The Pod can be deleted with the following command:

kubectl delete po/wp