how to use nfs storage in crunchydata postgres operator - postgresql

Question

I am trying out the CrunchyData postgres-operator(Helm) with the NFS Helm chart. And I am unable to create the Cluster with NFS. The following configuration is performed:
Installed NFS helm chart Repo
helm install nfs-abc stable/nfs-server-provisioner
Set the postgres storage values Doc
backrest_storage: 'nfsstorage'
backup_storage: 'nfsstorage'
primary_storage: 'nfsstorage'
replica_storage: 'nfsstorage'
Set the storage configuration Doc
export CCP_SECURITY_CONTEXT='"supplementalGroups": [65534]'
export CCP_STORAGE_PATH=/nfsfileshare
export CCP_NFS_IP=data-nfs-dravoka-nfs-server-provisioner-0.default.svc.cluster.local
export CCP_STORAGE_MODE=ReadWriteMany
export CCP_STORAGE_CAPACITY=400M
Created PGO cluster
pgo create cluster -n pgo dravoka --storage-config='nfsstorage' --pgbackrest-storage-config='nfsstorage' --pvc-size='2Gi'
PVC describe:
kubectl describe -n pgo pvc dravoka
Name: dravoka
Namespace: pgo
StorageClass: standard
Status: Pending
Volume:
Labels: pg-cluster=dravoka
pgremove=true
vendor=crunchydata
Annotations: volume.beta.kubernetes.io/storage-provisioner: kubernetes.io/gce-pd
Finalizers: [kubernetes.io/pvc-protection]
Capacity:
Access Modes:
VolumeMode: Filesystem
Mounted By: <none>
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Warning ProvisioningFailed 112s (x10 over 7m45s) persistentvolume-controller Failed to provision volume with StorageClass "standard": invalid AccessModes [ReadWriteMany]: only AccessModes [ReadWriteOnce ReadOnlyMany] are supported
Pod Describe:
kubectl describe -n pgo pod dravoka-backrest-shared-repo-9fdd77886-j2mjv
Name: dravoka-backrest-shared-repo-9fdd77886-j2mjv
Namespace: pgo
Priority: 0
Node: <none>
Labels: name=dravoka-backrest-shared-repo
pg-cluster=dravoka
pg-pod-anti-affinity=preferred
pgo-backrest-repo=true
pod-template-hash=9fdd77886
service-name=dravoka-backrest-shared-repo
vendor=crunchydata
Annotations: <none>
Status: Pending
IP:
IPs: <none>
Controlled By: ReplicaSet/dravoka-backrest-shared-repo-9fdd77886
Containers:
database:
Image: registry.developers.crunchydata.com/crunchydata/pgo-backrest-repo:centos7-4.4.1
Port: 2022/TCP
Host Port: 0/TCP
Requests:
memory: 48Mi
Environment:
PGBACKREST_STANZA: db
SSHD_PORT: 2022
PGBACKREST_DB_PATH: /pgdata/dravoka
PGBACKREST_REPO_PATH: /backrestrepo/dravoka-backrest-shared-repo
PGBACKREST_PG1_PORT: 5432
PGBACKREST_LOG_PATH: /tmp
PGBACKREST_PG1_SOCKET_PATH: /tmp
PGBACKREST_DB_HOST: dravoka
Mounts:
/backrestrepo from backrestrepo (rw)
/sshd from sshd (ro)
Conditions:
Type Status
PodScheduled False
Volumes:
sshd:
Type: Secret (a volume populated by a Secret)
SecretName: dravoka-backrest-repo-config
Optional: false
backrestrepo:
Type: PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
ClaimName: dravoka-pgbr-repo
ReadOnly: false
QoS Class: Burstable
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Warning FailedScheduling 76s (x7 over 9m58s) default-scheduler pod has unbound immediate PersistentVolumeClaims (repeated 2 times)
Am I missing something that too is configured or doing something wrong? my purpose is to use NFS as postgres storage. Any help will be appreciated.

Answer 1

Failed to provision volume with StorageClass "standard": invalid
AccessModes [ReadWriteMany]: only AccessModes [ReadWriteOnce
ReadOnlyMany] are supported
So here is the root cause of the problem. You are provisioning the pvc using storage class that does not support the AccessModes that you want i.e. ReadWriteMany
Looking at the doc, seems like you have having this configuration
storage3_name: 'nfsstorage'
storage3_access_mode: 'ReadWriteMany'
storage3_size: '1G'
storage3_type: 'create'
storage3_supplemental_groups: 65534
Where the storage3_access_mode is saying that the access_mode is ReadWriteMany but this is not supported.
Please try to change it to ReadWriteOnce
Anw, Postgres requires block storage to work so even when you get the NFS setup right, your Postgres cluster will not run anyway. More explanation here