Chapter 8. Storage

Procedure

1. Open the HyperConverged CR in your default editor by running the following command:

   $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv

2. Define a new storage class by entering a value in the storageClassName field:

   apiVersion: hco.kubevirt.io/v1beta1
   kind: HyperConverged
   metadata:
     name: kubevirt-hyperconverged
   spec:
     dataImportCronTemplates:
     - metadata:
         name: rhel8-image-cron
       spec:
         template:
           spec:
             storageClassName: <new_storage_class> 1
         schedule: "0 */12 * * *" 2
         managedDataSource: <data_source> 3
   # ...

   1

   Define the storage class.

   2

   Required: Schedule for the job specified in cron format.

   3

   Required: The data source to use.

   For the custom image to be detected as an available boot source, the value of the `spec.dataVolumeTemplates.spec.sourceRef.name` parameter in the VM template must match this value.

3. Remove the storageclass.kubernetes.io/is-default-class annotation from the current default storage class.

   1. Retrieve the name of the current default storage class by running the following command:

      $ oc get storageclass

      Example output

      NAME                          PROVISIONER                      RECLAIMPOLICY  VOLUMEBINDINGMODE    ALLOWVOLUMEEXPANSION  AGE
      csi-manila-ceph               manila.csi.openstack.org         Delete         Immediate            false                 11d
      hostpath-csi-basic (default)  kubevirt.io.hostpath-provisioner Delete         WaitForFirstConsumer false                 11d 1

      1

      In this example, the current default storage class is named hostpath-csi-basic.

   2. Remove the annotation from the current default storage class by running the following command:

      $ oc patch storageclass <current_default_storage_class> -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"false"}}}' 1

      1

      Replace <current_default_storage_class> with the storageClassName value of the default storage class.

4. Set the new storage class as the default by running the following command:

   $ oc patch storageclass <new_storage_class> -p '{"metadata":{"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}' 1

   1

   Replace <new_storage_class> with the storageClassName value that you added to the HyperConverged CR.

Procedure

1. Open the HyperConverged CR in your default editor by running the following command:

   $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv

2. Edit the HyperConverged CR, adding the appropriate template and boot source in the dataImportCronTemplates section. For example:

   Example custom resource

   apiVersion: hco.kubevirt.io/v1beta1
   kind: HyperConverged
   metadata:
     name: kubevirt-hyperconverged
   spec:
     dataImportCronTemplates:
     - metadata:
         name: centos7-image-cron
         annotations:
           cdi.kubevirt.io/storage.bind.immediate.requested: "true" 1
       spec:
         schedule: "0 */12 * * *" 2
         template:
           spec:
             source:
               registry: 3
                 url: docker://quay.io/containerdisks/centos:7-2009
             storage:
               resources:
                 requests:
                   storage: 10Gi
         managedDataSource: centos7 4
         retentionPolicy: "None" 5

   1

   This annotation is required for storage classes with volumeBindingMode set to WaitForFirstConsumer.

   2

   Schedule for the job specified in cron format.

   3

   Use to create a data volume from a registry source. Use the default pod pullMethod and not node pullMethod, which is based on the node docker cache. The node docker cache is useful when a registry image is available via Container.Image, but the CDI importer is not authorized to access it.

   4

   For the custom image to be detected as an available boot source, the name of the image’s managedDataSource must match the name of the template’s DataSource, which is found under spec.dataVolumeTemplates.spec.sourceRef.name in the VM template YAML file.

   5

   Use All to retain data volumes and data sources when the cron job is deleted. Use None to delete data volumes and data sources when the cron job is deleted.

3. Save the file.

Procedure

1. Open the storage profile object that corresponds to the storage class used to provision boot sources by running the following command:

   $ oc edit storageprofile <storage_class>

2. Review the dataImportCronSourceFormat specification of the StorageProfile to confirm whether or not the VM is using PVC or volume snapshot by default.

3. Edit the storage profile, if needed, by updating the dataImportCronSourceFormat specification to snapshot.

   Example storage profile

   apiVersion: cdi.kubevirt.io/v1beta1
   kind: StorageProfile
   metadata:
   # ...
   spec:
     dataImportCronSourceFormat: snapshot

Verification

1. Open the storage profile object that corresponds to the storage class used to provision boot sources.

   $ oc get storageprofile <storage_class>  -oyaml

2. Confirm that the dataImportCronSourceFormat specification of the StorageProfile is set to 'snapshot', and that any DataSource objects that the DataImportCron points to now reference volume snapshots.

Procedure

1. Create a storageclass_csi.yaml file to define the storage class:

   apiVersion: storage.k8s.io/v1
   kind: StorageClass
   metadata:
     name: hostpath-csi
   provisioner: kubevirt.io.hostpath-provisioner
   reclaimPolicy: Delete 1
   volumeBindingMode: WaitForFirstConsumer 2
   parameters:
     storagePool: my-storage-pool 3

   1

   The two possible reclaimPolicy values are Delete and Retain. If you do not specify a value, the default value is Delete.

   2

   The volumeBindingMode parameter determines when dynamic provisioning and volume binding occur. Specify WaitForFirstConsumer to delay the binding and provisioning of a persistent volume (PV) until after a pod that uses the persistent volume claim (PVC) is created. This ensures that the PV meets the pod’s scheduling requirements.

   3

   Specify the name of the storage pool defined in the HPP CR.

2. Save the file and exit.

3. Create the StorageClass object by running the following command:

   $ oc create -f storageclass_csi.yaml

Procedure

1. Create an hpp_pvc_template_pool.yaml file for the HPP CR that specifies a persistent volume (PVC) template in the storagePools stanza according to the following example:

   apiVersion: hostpathprovisioner.kubevirt.io/v1beta1
   kind: HostPathProvisioner
   metadata:
     name: hostpath-provisioner
   spec:
     imagePullPolicy: IfNotPresent
     storagePools: 1
     - name: my-storage-pool
       path: "/var/myvolumes" 2
       pvcTemplate:
         volumeMode: Block 3
         storageClassName: my-storage-class 4
         accessModes:
         - ReadWriteOnce
         resources:
           requests:
             storage: 5Gi 5
     workload:
       nodeSelector:
         kubernetes.io/os: linux

   1

   The storagePools stanza is an array that can contain both basic and PVC template storage pools.

   2

   Specify the storage pool directories under this node path.

   3

   Optional: The volumeMode parameter can be either Block or Filesystem as long as it matches the provisioned volume format. If no value is specified, the default is Filesystem. If the volumeMode is Block, the mounting pod creates an XFS file system on the block volume before mounting it.

   4

   If the storageClassName parameter is omitted, the default storage class is used to create PVCs. If you omit storageClassName, ensure that the HPP storage class is not the default storage class.

   5

   You can specify statically or dynamically provisioned storage. In either case, ensure the requested storage size is appropriate for the volume you want to virtually divide or the PVC cannot be bound to the large PV. If the storage class you are using uses dynamically provisioned storage, pick an allocation size that matches the size of a typical request.

2. Save the file and exit.

3. Create the HPP with a storage pool by running the following command:

   $ oc create -f hpp_pvc_template_pool.yaml