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VMware vSphere CSI Driver Operator

Overview

OKD can provision persistent volumes (PVs) using the Container Storage Interface (CSI) VMware vSphere driver for Virtual Machine Disk (VMDK) volumes.

Familiarity with persistent storage and configuring CSI volumes is recommended when working with a CSI Operator and driver.

To create CSI-provisioned persistent volumes (PVs) that mount to vSphere storage assets, OKD installs the vSphere CSI Driver Operator and the vSphere CSI driver by default in the openshift-cluster-csi-drivers namespace.

  • vSphere CSI Driver Operator: The Operator provides a storage class, called thin-csi, that you can use to create persistent volumes claims (PVCs). The vSphere CSI Driver Operator supports dynamic volume provisioning by allowing storage volumes to be created on-demand, eliminating the need for cluster administrators to pre-provision storage.

  • vSphere CSI driver: The driver enables you to create and mount vSphere PVs. In OKD 4.10, the driver version is 2.4.1. The vSphere CSI driver supports all of the file systems supported by the underlying Red Hat Core OS release, including XFS and Ext4. For more information about supported file systems, see Overview of available file systems.

OKD defaults to using an in-tree (non-CSI) plugin to provision vSphere storage.

In future OKD versions, volumes provisioned using existing in-tree plugins are planned for migration to their equivalent CSI driver. CSI automatic migration should be seamless. Migration does not change how you use all existing API objects, such as persistent volumes, persistent volume claims, and storage classes. For more information about migration, see CSI automatic migration.

After full migration, in-tree plugins will eventually be removed in future versions of OKD.

The vSphere CSI Driver supports dynamic and static provisioning. When using static provisioning in the PV specifications, do not use the key storage.kubernetes.io/csiProvisionerIdentity in csi.volumeAttributes because this key indicates dynamically provisioned PVs.

About CSI

Storage vendors have traditionally provided storage drivers as part of Kubernetes. With the implementation of the Container Storage Interface (CSI), third-party providers can instead deliver storage plugins using a standard interface without ever having to change the core Kubernetes code.

CSI Operators give OKD users storage options, such as volume snapshots, that are not possible with in-tree volume plugins.

vSphere storage policy

The vSphere CSI Operator Driver storage class uses vSphere’s storage policy. OKD automatically creates a storage policy that targets datastore configured in cloud configuration:

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: thin-csi
provisioner: csi.vsphere.vmware.com
parameters:
  StoragePolicyName: "$openshift-storage-policy-xxxx"
volumeBindingMode: WaitForFirstConsumer
allowVolumeExpansion: false
reclaimPolicy: Delete

ReadWriteMany vSphere volume support

If the underlying vSphere environment supports the vSAN file service, then vSphere Container Storage Interface (CSI) Driver Operator installed by OKD supports provisioning of ReadWriteMany (RWX) volumes. If vSAN file service is not configured, then ReadWriteOnce (RWO) is the only access mode available. If you do not have vSAN file service configured, and you request RWX, the volume fails to get created and an error is logged.

For more information about configuring the vSAN file service in your environment, see vSAN File Service.

You can request RWX volumes by making the following persistent volume claim (PVC):

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: myclaim
spec:
  resources:
    requests:
      storage: 1Gi
  accessModes:
     - ReadWriteMany
  storageClassName: thin-csi

Requesting a PVC of the RWX volume type should result in provisioning of persistent volumes (PVs) backed by the vSAN file service.

VMware vSphere CSI Driver Operator requirements

To install the vSphere CSI Driver Operator, the following requirements must be met:

  • VMware vSphere version 6.7U3 or later

  • Virtual machines of hardware version 15 or later

  • No third-party vSphere CSI driver already installed in the cluster

If a third-party vSphere CSI driver is present in the cluster, OKD does not overwrite it. If you continue with the third-party vSphere CSI driver when upgrading to the next major version of OKD, the oc CLI prompts you with the following message:

VSphereCSIDriverOperatorCRUpgradeable: VMwareVSphereControllerUpgradeable:
found existing unsupported csi.vsphere.vmware.com driver

The previous message informs you that Red Hat does not support the third-party vSphere CSI driver during an OKD upgrade operation. You can choose to ignore this message and continue with the upgrade operation.

To remove a third-party CSI driver, see Removing a third-party vSphere CSI Driver.

Removing a third-party vSphere CSI Operator Driver

OKD 4.10 includes a built-in version of the vSphere Container Storage Interface (CSI) Operator Driver that is supported by Red Hat.

If you have installed a vSphere CSI driver provided by the community or another vendor, which is considered a third-party vSphere CSI driver, and you continue with upgrading to the next major version of OKD, the oc CLI prompts you with the following message:

VSphereCSIDriverOperatorCRUpgradeable: VMwareVSphereControllerUpgradeable:
found existing unsupported csi.vsphere.vmware.com driver

The previous message informs you that Red Hat does not support the third-party vSphere CSI driver during an OKD upgrade operation. You can choose to ignore this message and continue with the upgrade operation.

The instructions outlined in the procedure show how to uninstall a third-party vSphere CSI Driver. Consult the vendor’s or community provider’s uninstall guide for more detailed instructions on removing the driver and its components.

When removing a third-party vSphere CSI driver, you do not need to delete the associated persistent volume (PV) objects. Data loss typically does not occur, but Red Hat does not take any responsibility if data loss does occur.

After you have removed the third-party vSphere CSI Driver from the OKD cluster, installation of Red Hat’s vSphere CSI Operator Driver automatically resumes. If you had existing vSphere CSI PV objects, their lifecycle is now managed by Red Hat’s vSphere CSI Operator Driver.

Procedure

  1. Delete the third-party vSphere CSI Driver (VMware vSphere Container Storage Plugin) Deployment and Daemonset objects.

  2. Delete the configmap and secret objects that were installed previously with the third-party vSphere CSI Driver.

  3. Delete the third-party vSphere CSI driver CSIDriver object:

    ~ $ oc delete CSIDriver csi.vsphere.vmware.com
    csidriver.storage.k8s.io "csi.vsphere.vmware.com" deleted

After you have removed the third-party vSphere CSI Driver from the OKD cluster, installation of Red Hat’s vSphere CSI Operator Driver automatically resumes, and any conditions that could block upgrades to OKD 4.11, or later, are automatically removed. If you had existing vSphere CSI PV objects, their lifecycle is now managed by Red Hat’s vSphere CSI Operator Driver.

Additional resources