HPE SimpliVity CSI Driver - Block Volumes
There are two types of volume provisioning in a Kubernetes cluster:
Dynamically Provisioning a Volume
Dynamically provisioning a volume allows storage volumes to be created on-demand.
The dynamic provisioning eliminates the need for cluster administrators to pre-provision storage. Instead, it automatically provisions storage when it is requested by a user.
The implementation of dynamic volume provisioning is based on the API object StorageClass from the API group storage.k8s.io. A cluster administrator can define as many StorageClass objects as needed, each specifying a volume plugin (a.k.a provisioner) that provisions a volume and a set of parameters to that provisioner when provisioning. A cluster administrator can define and expose multiple flavors of storage (from the same or different storage systems) within a cluster, each with a custom set of parameters.
How to Dynamically Provision a Block Volume on a Kubernetes Cluster
Define a StorageClass for the HPE SimpliVity CSI driver as the provisioner. A datastore URL or storage policy can be used to further restrict which datastore will be used by this storage class. In this case, neither are specified which means the driver will select the SimpliVity datastore with the most free space:
# Contents of example-sc.yaml
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: simplivity-sc
annotations:
storageclass.kubernetes.io/is-default-class: "false"
provisioner: csi.simplivity.hpe.com
parameters:
# datastoreurl and storagepolicyname are mutually exclusive.
# datastoreurl: "ds:///vmfs/volumes/9c8391e9-05250c25/" # Storage URL, found under storage tab in vCenter
# storagepolicyname: "policy-name" # Policy on selected datastore, from vCenter
# Optional Parameter
fstype: "ext4"Create this StorageClass into the Kubernetes Cluster:
$ kubectl create -f example-sc.yamlDefine a PersistentVolumeClaim:
# Contents of example-dynamic-pvc.yaml
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: example-dynamic-pvc
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 5Gi
storageClassName: simplivity-scCreate this PersistentVolumeClaim in the Kubernetes Cluster:
$ kubectl create -f example-dynamic-pvc.yamlA PersistentVolume is dynamically created and is bound to this PersistentVolumeClaim. Verify that the PersistentVolumeClaim was created and a PersistentVolume is attached to it.
The base status should show Bound if it worked and the Volume field should be populated.
$ kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
example-dynamic-pvc Bound pvc-f6fb41c4-fda5-4768-9a68-3cb8b27967da 5Gi RWO simplivity-sc 2m19sDetails of the PVC
$ kubectl describe pvc example-dynamic-pvc
Name: example-dynamic-pvc
Namespace: default
StorageClass: simplivity-sc
Status: Bound
Volume: pvc-f6fb41c4-fda5-4768-9a68-3cb8b27967da
Labels: <none>
Annotations: pv.kubernetes.io/bind-completed: yes
pv.kubernetes.io/bound-by-controller: yes
volume.beta.kubernetes.io/storage-provisioner: csi.simplivity.hpe.com
Finalizers: [kubernetes.io/pvc-protection]
Capacity: 5Gi
Access Modes: RWO
VolumeMode: Filesystem
Mounted By: <none>
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Provisioning 3m48s csi.simplivity.hpe.com_svt-csi-controller-0_e9cdfeaf-603c-45a4-837b-3e5b86beb6d7 External provisioner is provisioning volume for claim "default/example-dynamic-pvc"
Normal ExternalProvisioning 3m8s (x4 over 3m48s) persistentvolume-controller waiting for a volume to be created, either by external provisioner "csi.simplivity.hpe.com" or manually created by system administrator
Normal ProvisioningSucceeded 2m56s csi.simplivity.hpe.com_svt-csi-controller-0_e9cdfeaf-603c-45a4-837b-3e5b86beb6d7 Successfully provisioned volume pvc-f6fb41c4-fda5-4768-9a68-3cb8b27967daHere, ReadWriteOnce (RWO) access mode indicates that the volume provisioned is a Block Volume. In both the basic get information and the detailed describe information of the PVC, the volume is shown in the Volume field.
$ kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvc-f6fb41c4-fda5-4768-9a68-3cb8b27967da 5Gi RWO Delete Bound default/example-dynamic-pvc simplivity-sc 8m27s
$ kubectl describe pv pvc-f6fb41c4-fda5-4768-9a68-3cb8b27967da
Name: pvc-f6fb41c4-fda5-4768-9a68-3cb8b27967da
Labels: <none>
Annotations: pv.kubernetes.io/provisioned-by: csi.simplivity.hpe.com
Finalizers: [kubernetes.io/pv-protection]
StorageClass: simplivity-sc
Status: Bound
Claim: default/example-dynamic-pvc
Reclaim Policy: Delete
Access Modes: RWO
VolumeMode: Filesystem
Capacity: 5Gi
Node Affinity: <none>
Message:
Source:
Type: CSI (a Container Storage Interface (CSI) volume source)
Driver: csi.simplivity.hpe.com
VolumeHandle: d3cff17d-334a-4217-b55d-e478648c5b8d
ReadOnly: false
VolumeAttributes: datastoreurl=ds:///vmfs/volumes/188e6f22-173b61ae/
fstype=ext4
storage.kubernetes.io/csiProvisionerIdentity=1589547226925-8081-csi.simplivity.hpe.com
type=HPE SimpliVity CNS Block Volume
Events: <none>The Status: in both the outputs say bound and the Claim: points to the PVC that was created earlier default/example-dynamic-pvc.
This created a new volume and attached it to the application for the user.
Statically Provisioning a Volume
Use this method when there is already an existing volume that is wanted by the Kubernetes cluster. Static provisioning is a feature that is native to Kubernetes and that allows cluster administrators to make existing storage devices available to a cluster.
As a cluster administrator, you must know the details of the storage device, its supported configurations, and mount options.
To make existing storage available to a cluster user, you must manually create the storage device, a PeristentVolume, and a PersistentVolumeClaim. Because the PV and the storage device already exists, there is no need to specify a storage class name in the PVC spec. There are many ways to create a static PV and PVC binding, some examples are label matching, volume size matching etc...
Use Cases of Static Provisioning
Common use cases supported for static volume provisioning:
-
Use an existing storage device: You provisioned a persistent storage First Class Disk (FCD) directly in your VC and want to use this FCD in your cluster.
-
Make retained data available to the cluster: You provisioned a volume with a
reclaimPolicy: retainin the storage class by using dynamic provisioning. You removed the PVC, but the PV, the physical storage in the VC, and the data still exist. You want to access the retained data from the same or another app in your cluster.
How to Statically Provision a Block Volume on a Kubernetes Cluster
First a FCD ID will need to be obtained for the volume. If the volume is not already a FCD it will need to be registered as one. This command will regiseter the volume as a FCD and return the FCD ID
$ govc disk.register -ds=<datastore name> <myVMDKdirectory/mydisk.vmdk> <new FCD name>If the volume is already a FCD, the FCD ID can be retrieved with the PowerCLI or govc utility
- PowerCLI
$ Connect-VIServer <vCenter ip> -User administrator@vsphere.local -Password <vCenter password>
$ (Get-VDisk -Name <new FCD name>).id.Split(':')[1]
3515afd9-150e-4603-9267-7f0ff165ae63- GOVC
$ govc disk.ls
3515afd9-150e-4603-9267-7f0ff165ae63 static-pvDefine a PersistentVolume (PV) that links a FCD to Kubernetes
apiVersion: v1
kind: PersistentVolume
metadata:
name: static-pv-name # Set name of new PV
labels:
"fcd-id": "3515afd9-150e-4603-9267-7f0ff165ae63"
# This label is used as selector to bind with volume claim.
# This can we any unique key-value to identify PV.
spec:
capacity:
storage: 1Gi
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Retain
csi:
driver: csi.simplivity.hpe.com # make sure this says `csi.simplivity.hpe.com`
fsType: ext4
volumeAttributes:
fstype: ""
storage.kubernetes.io/csiProvisionerIdentity: static-pv-name-csi.simplivity.hpe.com # update this
type: "vSphere CNS Block Volume"
datastoreurl: "ds:///vmfs/volumes/9c8391e9-05250c25/" # Storage URL, found under storage tab in vCenter
volumeHandle: 3515afd9-150e-4603-9267-7f0ff165ae63 # First Class Disk (Improved Virtual Disk) IDDefine a PersistentVolumeClaim (PVC), which makes the PV useable by another Kubernetes resource like a Pod or StatefulSet.
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: static-pvc-name
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
selector:
matchLabels:
fcd-id: 3515afd9-150e-4603-9267-7f0ff165ae63 # This label is used as selector to find matching PV with specified key and value.
storageClassName: ""Create a static PV
$ kubectl apply -f static-pv.yaml
persistentvolume/static-pv-name created
$ kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
static-pv-name 1Gi RWO Retain Available 5sCreate PVC for the static PV. The PVC will be bound to the PV in the Volume column. While the PV will be updated with a Claim and the Status will be updated to Bound.
$ kubectl apply -f static-pvc.yaml
persistentvolumeclaim/static-pvc-name created
$ kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
static-pvc-name Bound static-pv-name 1Gi RWO 8s
$ kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
static-pv-name 1Gi RWO Retain Bound default/static-pvc-name 2mThe PV is now ready to be used by Kubernetes through the PVC it is bound to.