Description: Unable to bind a new PVC to an existing PV that already contains data from previous run (and was dynamically created using gluster storage class).
helm del) and re-install it (helm install). However, want to use the existing PV instead of creating a new one.I tried a few things: - Following the instruction here: https://github.com/kubernetes/kubernetes/issues/48609. However, that did not work for GlusterFS storage solution since after I tried the needed steps, it complained:
Type Reason Age From Message
---- ------ ---- ---- -------
Warning FailedScheduling <unknown> default-scheduler error while running "VolumeBinding" filter plugin for pod "opensync-wifi-controller-opensync-mqtt-broker-fbbd69676-bmqqm": pod has unbound immediate PersistentVolumeClaims
Warning FailedScheduling <unknown> default-scheduler error while running "VolumeBinding" filter plugin for pod "opensync-wifi-controller-opensync-mqtt-broker-fbbd69676-bmqqm": pod has unbound immediate PersistentVolumeClaims
Normal Scheduled <unknown> default-scheduler Successfully assigned connectus/opensync-wifi-controller-opensync-mqtt-broker-fbbd69676-bmqqm to rahulk8node1-virtualbox
Warning FailedMount 31s (x7 over 62s) kubelet, rahulk8node1-virtualbox MountVolume.NewMounter initialization failed for volume "pvc-dc52b290-ae86-4cb3-aad0-f2c806a23114" : endpoints "glusterfs-dynamic-dc52b290-ae86-4cb3-aad0-f2c806a23114" not found
Warning FailedMount 30s (x7 over 62s) kubelet, rahulk8node1-virtualbox MountVolume.NewMounter initialization failed for volume "pvc-735baedf-323b-47bc-9383-952e6bc5ce3e" : endpoints "glusterfs-dynamic-735baedf-323b-47bc-9383-952e6bc5ce3e" not found
Apparently besides the PV, we would also need to persist gluster-dynamic-endpoints and glusterfs-dynamic-service. However, these are created in the pod namespace and since the namespace is removed as part of helm del, it also deletes these endpoints and svc.
I looked around other pages related to GlusterFS endpoint missing: https://github.com/openshift/origin/issues/6331 but that does not applies to the current version of Storage class. When I added endpoint: "heketi-storage-endpoints" to the Storage class parameters, I got the following error when creating the PVC:
Failed to provision volume with StorageClass "glusterfs-storage": invalid option "endpoint" for volume plugin kubernetes.io/glusterfs
This option was removed in 2016 - see https://github.com/gluster/gluster-kubernetes/issues/87.
Is there anyway to use existing PV from a new PVC?
I would like to suggest a different approach.
You can use this annotation on the PVC, it will skip deleting the resource on delete.
helm.sh/resource-policy: "keep"
Here is an example:
{{- if and .Values.persistence.enabled (not .Values.persistence.existingClaim) }}
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: {{ template "bitcoind.fullname" . }}
annotations:
"helm.sh/resource-policy": keep
labels:
app: {{ template "bitcoind.name" . }}
chart: "{{ .Chart.Name }}-{{ .Chart.Version }}"
release: "{{ .Release.Name }}"
heritage: "{{ .Release.Service }}"
spec:
accessModes:
- {{ .Values.persistence.accessMode | quote }}
resources:
requests:
storage: {{ .Values.persistence.size | quote }}
{{- if .Values.persistence.storageClass }}
{{- if (eq "-" .Values.persistence.storageClass) }}
storageClassName: ""
{{- else }}
storageClassName: "{{ .Values.persistence.storageClass }}"
{{- end }}
{{- end }}
{{- end }}
You can also use parameters as seen here, where they implemented an option to flag (which is either true or false) while you install your helm chart.
persistence.annotations."helm.sh/resource-policy"
You can also include a configurable parameters to set the name of the pvc you want to reuse as seen here.
In this example you can set persistence.existingClaim=mysql-pvc during your chart install.
So mixing everything you can have something that should look like this when you run your helm install:
helm install --namespace myapp --set existingClaim=mysql-pvc stable/myapp