Using VMware vSphere volumes for persistent storage
OKD supports VMware vSphere’s Virtual Machine Disk (VMDK) volumes. You can provision your OKD cluster with persistent storage using VMware vSphere. Some familiarity with Kubernetes and VMware vSphere is assumed.
OKD creates the disk in vSphere and attaches the disk to the correct instance.
The OKD persistent volume (PV) framework allows administrators to provision a cluster with persistent storage and gives users a way to request those resources without having any knowledge of the underlying infrastructure. vSphere VMDK volumes can be provisioned dynamically.
PVs are not bound to a single project or namespace; they can be shared across the OKD cluster. PV claims, however, are specific to a project or namespace and can be requested by users.
High availability of storage in the infrastructure is left to the underlying storage provider.
Before creating PVs using vSphere, ensure your OKD cluster meets the following requirements:
OKD must first be configured for vSphere.
Each node host in the infrastructure must match the vSphere VM name.
Each node host must be in the same resource group.
Dynamically provisioning VMware vSphere volumes is the preferred provisioning method.
If you did not specify the
openshift_vsphere_*variables in the Ansible inventory file when you provisioned the cluster, you must manually create the following
StorageClassto use the
$ oc get --export storageclass vsphere-standard -o yaml kind: StorageClass apiVersion: storage.k8s.io/v1 metadata: name: "vsphere-standard" (1) provisioner: kubernetes.io/vsphere-volume (2) parameters: diskformat: thin (3) datastore: "YourvSphereDatastoreName" (4) reclaimPolicy: Delete
1 The name of the StorageClass. 2 The type of storage provisioner. Specify
3 The type of disk. Specify either
4 The source datastore where the disks will be created.
After you request a PV, using the StorageClass shown in the previous step, OKD automatically creates VMDK disks in the vSphere infrastructure. To verify that the disks were created, use the Datastore browser in vSphere.
vSphere-volume disks are
ReadWriteOnceaccess mode, which means the volume can be mounted as read-write by a single node. See the Access modes section of the Architecture guide for more information.
Storage must exist in the underlying infrastructure before it can be mounted as a volume in OKD. After ensuring OKD is configured for vSphere, all that is required for OKD and vSphere is a VM folder path, file system type, and the
Create VMDK using one of the following methods before using them.
Access ESX through Secure Shell (SSH) and then use following command to create a VMDK volume:
vmkfstools -c 40G /vmfs/volumes/DatastoreName/volumes/myDisk.vmdk
shell vmware-vdiskmanager -c -t 0 -s 40GB -a lsilogic myDisk.vmdk
Define a PV object definition, for example vsphere-pv.yaml:
apiVersion: v1 kind: PersistentVolume metadata: name: pv0001 (1) spec: capacity: storage: 2Gi (2) accessModes: - ReadWriteOnce persistentVolumeReclaimPolicy: Retain vsphereVolume: (3) volumePath: "[datastore1] volumes/myDisk" (4) fsType: ext4 (5)
1 The name of the volume. This must be how it is identified by PV claims or from pods. 2 The amount of storage allocated to this volume. 3 The volume type being used. This example uses
vsphereVolume. The label is used to mount a vSphere VMDK volume into pods. The contents of a volume are preserved when it is unmounted. The volume type supports VMFS and VSAN datastore.
4 The existing VMDK volume to use. You must enclose the datastore name in square brackets () in the volume definition, as shown. 5 The file system type to mount. For example,
xfs, or other file-systems.
Changing the value of the
fsTypeparameter after the volume is formatted and provisioned can result in data loss and pod failure.
Create the PV:
$ oc create -f vsphere-pv.yaml persistentvolume "pv0001" created
Verify that the PV was created:
$ oc get pv NAME LABELS CAPACITY ACCESSMODES STATUS CLAIM REASON AGE pv0001 <none> 2Gi RWO Available 2s
Now you can request storage using PV claims, which can now use your PV.
PV claims only exist in the user’s namespace and can only be referenced by a pod within that same namespace. Any attempt to access a PV from a different namespace causes the pod to fail.
Before OKD mounts the volume and passes it to a container, it checks that the volume contains a file system as specified by the
fsType parameter in the PV definition. If the device is not formatted with the file system, all data from the device is erased, and the device is automatically formatted with the given file system.
Because OKD formats them before the first use, you can use unformatted vSphere volumes as PVs.