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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.

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

In future OKD versions, volumes provisioned using existing in-tree plug-ins 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 plug-ins 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 plug-ins 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 plug-ins.

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

VMware vSphere CSI Driver Operator requirements

The following requirements must be met in order to install the CSI Driver Operator:

  • VMware vSphere version 7.0.1 or later

  • Virtual machines of hardware version 15 or later

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

If a third-party CSI driver is present in the cluster, OKD does not overwrite it. The presence of a third-party CSI driver prevents OKD from upgrading in a future release.

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, upgrades will be prevented in a future release of OKD.

If you remove the third-party vSphere CSI driver, you do not need to delete associated persistent volume (PV) objects, and no data loss should occur.

These instructions may not be complete, so consult the vendor or community provider uninstall guide to ensure removal of the driver and components.

To uninstall the third-party vSphere CSI Driver:

  1. Delete the third-party vSphere CSI Driver (VMware vSphere Container Storage Plug-in) 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