Declare a Backend within a PVC.yaml | NetApp | Page 1

lime trench Feb 28, 2025, 10:38 AM

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Hi everybody. I am playing around with trident and created multiple backends that use different Data-LIFs. I now want to control the backend my PVs get provisioned to, when I create a PVC. However I have not found any documentation about this, is it even possible?

I know that I can import existing volumes in ONTAP with tridentctl and specify a backend. So theoretically I should be able to specify the Backend in my PVC?

Thanks in advance!

mint marsh Feb 28, 2025, 12:05 PM

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https://kb.netapp.com/Cloud/Astra/Trident/How_Trident_uses_labels_to_selects_the_correct_backend
will show you how to use labels and selectors to specify a backend from a storage class. From the PVC level, simply specify the storage class you want to use.

NetApp Knowledge Base

How Trident uses labels to select the correct backend

pearl terrace Feb 28, 2025, 2:32 PM

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yeah, the chain goes PVC->StorageClass->Backend so for multiple backends you need multiple StorageClasses. You should also make sure that only one of them has the "default" annotation otherwise it will be a bit random if you forget to specify the SC in the PVC

lime trench Feb 28, 2025, 2:33 PM

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I tested it and it seems like the selector flag is not supported on the storage-class in the yaml format. Do I have to use the json format with tridentctl?

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This is my sc yaml.

---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: test1
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
provisioner: csi.trident.netapp.io
parameters:
  backendType: "ontap-nas"
  provisioningType: "thin"
  snapshots: "true"
selector: "test=lif1"
reclaimPolicy: Delete
allowVolumeExpansion: true

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The error:

StorageClass in version "v1" cannot be handled as a StorageClass: strict decoding error: unknown field "selector"

pearl terrace Feb 28, 2025, 2:42 PM

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selector should be under parameters, not at top level

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something like

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: test1
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
provisioner: csi.trident.netapp.io
parameters:
  backendType: "ontap-nas"
  selector: "cluster=cl1; disktype=sata"
allowVolumeExpansion: true

lime trench Feb 28, 2025, 2:54 PM

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I've tried that too, but then trident doesn't recognize the storageclass.

Tridentctl get storageclass is empty when I put it under parameters.

I guess my backend must be wrongly configured then.

The label on the backend is configured like this?

  storage:
    - labels:
        cluster: lif1

pearl terrace Feb 28, 2025, 2:58 PM

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the backend should look something like this:

apiVersion: trident.netapp.io/v1
kind: TridentBackendConfig
metadata:
  name: backend-test
  namespace: trident
spec:
  version: 1
  storageDriverName: ontap-nas
  managementLIF: 10.x.x.x
  dataLIF: 10.x.x.x
  backendName: backend-test
  storagePrefix: "test_"
  aggregate: aggrSATA
  credentials:
    name: trident-secret
  labels:
    k8scluster: prod
    cluster: cl1
    disktype: sata
  limitVolumeSize: 100Gi
  nfsMountOptions: nfsvers=3,rsize=65536,wsize=65536
  defaults:
    spaceReserve: none
    exportPolicy: default
    snapshotPolicy: none
    snapshotReserve: '0'
  deletionPolicy: retain

lime trench Feb 28, 2025, 3:10 PM

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Hmm it seems like dots are the problem. I had dots in the label value.

labels:
  cluster: test.lif1

Without the dot it works.

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Thank you for the support ❤️😊

lime trench Feb 28, 2025, 3:33 PM

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And capital characters also don't seem to work

#Declare a Backend within a PVC.yaml