HostPath CSI Driver for TrilioVault for Kubernetes

HostPath is a storage type where volumes refer to directories on the Node (VM/machine) where your Pod is scheduled for running.

In this section, we are going to see how to enable HostPath for your Kubernetes Cluster and test the VolumeSnapshot functionality which is the prerequisite for TrilioVault for Kubernetes.

Follow the steps below to install and validate the HostPath CSI driver :

1. Clone the hostpath GitHub repository:

   git clone https://github.com/kubernetes-csi/csi-driver-host-path.git

2. Go to the specific directory where the installation script is available. This depends on your Kubernetes cluster version

   cd csi-driver-host-path/deploy/kubernetes-1.XX

   ​

3. Skip this step if volumesnapshot, volumesnapshotcontent, volumesnapshotclass crds are already present on the cluster.

   # Change to the latest supported snapshotter version
   $ SNAPSHOTTER_VERSION=v2.0.1
   ​
   # Apply VolumeSnapshot CRDs
   $ kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/${SNAPSHOTTER_VERSION}/config/crd/snapshot.storage.k8s.io_volumesnapshotclasses.yaml
   $ kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/${SNAPSHOTTER_VERSION}/config/crd/snapshot.storage.k8s.io_volumesnapshotcontents.yaml
   $ kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/${SNAPSHOTTER_VERSION}/config/crd/snapshot.storage.k8s.io_volumesnapshots.yaml
   ​
   # Create snapshot controller
   $ kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/${SNAPSHOTTER_VERSION}/deploy/kubernetes/snapshot-controller/rbac-snapshot-controller.yaml
   $ kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/${SNAPSHOTTER_VERSION}/deploy/kubernetes/snapshot-controller/setup-snapshot-controller.yaml

4. Run the shell script based on your cluster OCP/K8s Version. Make sure you install this driver in the Default namespace

   ./deploy.sh

5. Wait for the installation to complete and verify if the driver is installed correctly.

   Make sure following pods are running
   ​
   NAME                                                  READY   STATUS      RESTARTS   AGE
   csi-hostpath-attacher-0                               1/1     Running     0          28d
   csi-hostpath-provisioner-0                            1/1     Running     1          28d
   csi-hostpath-resizer-0                                1/1     Running     0          28d
   csi-hostpath-snapshotter-0                            1/1     Running     0          28d
   csi-hostpath-socat-0                                  1/1     Running     0          28d
   csi-hostpathplugin-0                                  3/3     Running     0          28d

6. Create a Storage Class for Hostpath

   apiVersion: storage.k8s.io/v1
   kind: StorageClass
   metadata:
     name: csi-hostpath-sc
     annotations:
       storageclass.kubernetes.io/is-default-class: "true"
   provisioner: hostpath.csi.k8s.io
   reclaimPolicy: Retain
   volumeBindingMode: Immediate

7. Create a VolumeSnapshot Class for Hostpath. At this step, we need to use the API version based on K8s/OCP Version.

   • OCP 4.3/k8s 1.16 : apiVersion: snapshot.storage.k8s.io/v1alpha1

     apiVersion: snapshot.storage.k8s.io/v1alpha1
     kind: VolumeSnapshotClass
     metadata:
       annotations:
         snapshot.storage.kubernetes.io/is-default-class: "true"
       name: default-snapshot-class
     snapshotter: hostpath.csi.k8s.io

   • OCP 4.4/K8s 1.17+ : apiVersion: snapshot.storage.k8s.io/v1beta1

     apiVersion: snapshot.storage.k8s.io/v1beta1
     kind: VolumeSnapshotClass
     metadata:
       name: default-snapshot-class
     driver: hostpath.csi.k8s.io
     deletionPolicy: Delete

8. Create a test volume eg: task-pv-claim

   apiVersion: v1
   kind: PersistentVolumeClaim
   metadata:
     name: task-pv-claim
   spec:
     storageClassName: csi-hostpath-sc
     accessModes:
       - ReadWriteOnce
     resources:
       requests:
         storage: 50Mi

9. Create a snapshot of task-pv-claim.

   • If using the Alpha version of the API

     apiVersion: snapshot.storage.k8s.io/v1alpha1
     kind: VolumeSnapshot
     metadata:
      name: new-snapshot-demo
      namespace: default
     spec:
      snapshotClassName: default-snapshot-class
      source:
       name: task-pv-claim
       kind: PersistentVolumeClaim

   • If using the Beta version of the API

     apiVersion: snapshot.storage.k8s.io/v1beta1
     kind: VolumeSnapshot
     metadata:
       name: new-snapshot
     spec:
       volumeSnapshotClassName: default-snapshot-class
       source:
         persistentVolumeClaimName: task-pv-claim

10. Verify if snapshot and volume snapshot content shows created snapshot.

oc get volumesnapshot
oc get volumesnapshotcontent

kubectl get volumesnapshot
kubectl get volumesnapshotcontent