Kubernetes reattach to same persistent volume after delete - kubernetes

Question

I have a app where two pods needs to have access to the same volume. I want to be able to delete the cluster and then after apply to be able to access the data that is on the volume.
So for example:
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: retaining
provisioner: csi.hetzner.cloud
reclaimPolicy: Retain
volumeBindingMode: WaitForFirstConsumer
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: media
spec:
#storageClassName: retaining
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 10Gi
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: myapp-php
labels:
app: myapp-php
k8s-app: myapp
spec:
replicas: 1
selector:
matchLabels:
app: myapp-php
template:
metadata:
labels:
app: myapp-php
k8s-app: myapp
spec:
containers:
- image: nginx:1.17
imagePullPolicy: IfNotPresent
name: myapp-php
ports:
- containerPort: 9000
protocol: TCP
resources:
limits:
cpu: 750m
memory: 3Gi
requests:
cpu: 750m
memory: 3Gi
volumeMounts:
- name: media
mountPath: /var/www/html/media
volumes:
- name: media
persistentVolumeClaim:
claimName: media
nodeSelector:
mytype: main
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: myapp-web
labels:
app: myapp-web
k8s-app: myapp
spec:
selector:
matchLabels:
app: myapp-web
template:
metadata:
labels:
app: myapp-web
k8s-app: myapp
spec:
containers:
- image: nginx:1.17
imagePullPolicy: IfNotPresent
name: myapp-web
ports:
- containerPort: 9000
protocol: TCP
resources:
limits:
cpu: 10m
memory: 128Mi
requests:
cpu: 10m
memory: 128Mi
volumeMounts:
- name: media
mountPath: /var/www/html/media
volumes:
- name: media
persistentVolumeClaim:
claimName: media
nodeSelector:
mytype: main
If I do these:
k apply -f pv-issue.yaml
k delete -f pv-issue.yaml
k apply-f pv-issue.yaml
I want to connect the same volume.
What I have tried:
If I keep the file as is, the volume will be deleted so the data will be lost.
I can remove the pvc declaration from the file. Then it works. My issue that on the real app I am using kustomize and I don't see a way to exclude resources when doing kustomize build app | kubectl delete -f -
Tried using retain in the pvc. It retains the volume on delete, but on the apply a new volume is created.
Statefulset, however I don't see a way that to different statefulsets can share the same volume.
Is there a way to achieve this?
Or should I just do regular backups, and restore the volume data from backup when recreating the cluster?

Answer 1

Is there a way to achieve this? Or should I just do regular backups, and restore the volume data from backup when recreating the cluster?
Cluster deletion will make all your local volumes to be deleted. You can achieve this by storing the data outside the cluster. Kubernetes has a wide variety of storage providers to help you deploy data on a variety of storage types.
You may want to think also that you can keep the data locally on nodes with usage of hostPath but that is also not a good solution since it will require you to pin the pod to the specific node to avoid data loss. And if you delete you cluster in a way that all of you VM are gone, then this will be also gone.
Having some network-attached storage would be right way to go here. Very good example of those are Persistence disks which durable network storage devices that you instances can access. They're located independently from you virtuals machines and they are not being deleted when you delete the cluster.