Storage¶

After the cluster is running, install your vendor's CSI driver to provide persistent storage for workloads.

Storage Vendor Inclusion

It is highly recommended to bring your storage vendor in to assist directly in the installation and configuration of their CSI driver. While the Red Hat sales engineers are multidisciplinary and bring tons of expertise, it is impossible for them to keep up with the nuances and best practices of every single storage provider in the market.

OpenShift Virtualization Storage Requirements¶

If you are planning on running virtual machines using OpenShift Virtualization, the live migration feature requires shared storage with ReadWriteMany (RWX) access mode. A VM's disk PVCs must be RWX for it to migrate — during migration the VM runs briefly on both source and destination nodes, so the disk volume has to be mountable on two nodes at once, which RWO can't do.

CSI Driver Installation¶

Most vendors provide an Operator available through the Software Catalog or a Helm chart. The general process is:

Install the CSI driver Operator (or deploy via manifests provided by the vendor)
Configure the driver with storage array credentials and connectivity details
Create a StorageClass that references the CSI driver

Set the StorageClass as the cluster default:

oc patch storageclass {{ storage_class_name }} -p '{"metadata":{"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'

Verify¶

oc get csidrivers
oc get storageclass

Access Modes¶

Confirm with your storage vendor which access modes are supported:

Access Mode	Description	Common Use
RWO	Read-Write Once (single node)	Databases, monitoring
RWX	Read-Write Many (multiple nodes)	Registry, shared application data
ROX	Read-Only Many (multiple nodes)	Static content, shared configs

Vendor Compatibility¶

Verify your storage vendor and driver version are listed in the Red Hat Ecosystem Catalog for your target OpenShift version.

OpenShift Data Foundation¶

If you are targeting ODF as your storage provider, see the dedicated OpenShift Data Foundation installation guide.

NetApp Trident¶

If you are using NetApp ONTAP storage, see the NetApp Trident installation guide. Trident supports NFS (FlexVol and FlexGroup), iSCSI, NVMe/TCP, and Fibre Channel protocols.

Dell Unity XT¶

If you are using Dell Unity XT over iSCSI, see the Dell Unity XT installation guide.

VMware vSphere CSI¶

If the cluster is VMs on vSphere with platform: vsphere, see the VMware vSphere CSI guide.