Clear Kubernetes persistent volume on new image - wordpress

Question

I have a deployment of wordpress with a custom docker image with a custom theme copied into the image that gets deployed into a kubernetes cluster with a persistent volume.
The initial deployment works great and the website presents as expected. The problem comes when I update the theme and deploy a new docker image, because of the persistent volume the theme files don't seem to be updated to the new version of the theme in the docker image.
Is there a to clear/reset the wp-content/themes/my-theme directory when I deploy the new image?
Any help is appreciated and code samples below.
Dockerfile:
FROM wordpress:latest
COPY ./my-thtme /usr/src/wordpress/wp-content/themes/my-theme
Persistent Volume Claim:
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: wordpress
spec:
accessModes:
- ReadWriteMany
resources:
requests:
storage: 2Gi
storageClass: "nfs"
Deployment:
apiVersion: apps/v1
kind: Deployment
metadata:
name: wordpress
spec:
replicas: 2
strategy:
type: RollingUpdate
rollingUpdate:
maxSurge: 1
maxUnavailable: 0
selector:
matchLabels:
app: wordpress
template:
metadata:
labels:
app: wordpress
spec:
imagePullSecrets:
- name: gitlab-auth
containers:
- name: wordpress
image: registry.gitlab.com/user/wordpress:1234
imagePullPolicy: IfNotPresent
env:
- name: WORDPRESS_DB_HOST
value: wordpress-mysql
- name: WORDPRESS_DB_USER
value: mysql_wordpress
- name: WORDPRESS_DB_NAME
value: wordpress
- name: WORDPRESS_DB_TABLE_PREFIX
value: _wp
- name: WORDPRESS_DB_PASSWORD
valueFrom:
secretKeyRef:
name: mysql-pass
key: mysql-password
volumeMounts:
- name: wordpress-data
mountPath: /var/www/html/wp-content
ports:
- name: http
containerPort: 80
protocol: TCP
volumes:
- name: wordpress-data
persistentVolumeClaim:
claimName: wordpress

Answer 1

There is more than one way to do it. You could add an initContainer to the Deployment spec to remove existing files from the Persistent Volume before app containers in the Pod are started. For example:
apiVersion: apps/v1
kind: Deployment
metadata:
name: wordpress
spec:
replicas: 2
strategy:
type: RollingUpdate
rollingUpdate:
maxSurge: 1
maxUnavailable: 0
selector:
matchLabels:
app: wordpress
template:
metadata:
labels:
app: wordpress
spec:
imagePullSecrets:
- name: gitlab-auth
initContainers:
- name: init-theme
image: "alpine:3"
command: ["sh", "-c", "if [ -d /var/www/html/wp-content/my-theme ]; then rm -rf /var/www/html/wp-content/my-theme; fi"]
volumeMounts:
- name: workdpress-data
mountPath: /var/www/html/wp-content
containers:
...
volumes:
- name: wordpress-data
persistentVolumeClaim:
claimName: wordpress