Prerequisites for Installing the Container Storage Interface (CSI) Storage Plugin

Hardware and Software Requirements

*Kubernetes alpha features are not supported.

Before You Install

Before installing the Container Storage Interface (CSI) Storage Plugin, note that the installation procedure assumes that the Kubernetes cluster is already installed and functioning normally. In addition:

1. Ensure that all Kubernetes nodes use the same Linux distribution.

   For example, all nodes can be CentOS nodes, or all nodes can be Ubuntu nodes. A cluster with a mixture of CentOS and Ubuntu nodes is not supported.

2. Configure your Kubernetes cluster to allow privileged pods by running the following commands:

   $ ./kube-apiserver ...  --allow-privileged=true …

   $ ./kubelet ...  --allow-privileged=true ...

3. Enable mount propagation to share volumes mounted by one container with other containers in the same pod and other pods on the same node.

   For more information, see Mount Propagation.

4. Apply CRDs to your Kubernetes cluster if they are not already present:
   Kubernetes 1.26 and Later

   kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/v7.0.2/client/config/crd/snapshot.storage.k8s.io_volumesnapshotclasses.yaml
   kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/v7.0.2/client/config/crd/snapshot.storage.k8s.io_volumesnapshotcontents.yaml
   kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/v7.0.2/client/config/crd/snapshot.storage.k8s.io_volumesnapshots.yaml

   Kubernetes 1.20 and Later

   kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/v4.2.1/client/config/crd/snapshot.storage.k8s.io_volumesnapshotclasses.yaml
   kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/v4.2.1/client/config/crd/snapshot.storage.k8s.io_volumesnapshotcontents.yaml
   kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/v4.2.1/client/config/crd/snapshot.storage.k8s.io_volumesnapshots.yaml

   Kubernetes 1.19 and Earlier

   kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/release-3.0/client/config/crd/snapshot.storage.k8s.io_volumesnapshotclasses.yaml
   kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/release-3.0/client/config/crd/snapshot.storage.k8s.io_volumesnapshotcontents.yaml
   kubectl apply -f https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/release-3.0/client/config/crd/snapshot.storage.k8s.io_volumesnapshots.yaml

   For more information see Snapshot Controller.
5. For OpenShift, install the SecurityContextConstraints by applying deploy/openshift/csi-scc.yaml in the mapr-csi GitHub repository:

   oc apply -f deploy/openshift/csi-scc.yaml

6. Create the state volume-mount path, and update the CSI driver yaml. In prior releases, the state of dynamically provisioned volumes and their snapshots was held in memory. The provisioner would lose this state if the controller pod was restarted or upgraded. After restarts, the provisioner would fail to take snapshots, restore snapshots, resize or clone previously created volumes.

   With the latest version of the CSI driver, the provisioner persists the encrypted state of the dynamically provisioned volumes and their snapshots in a volume on the data-fabric cluster. If the controller pod is restarted, the state is automatically recovered, and operations on previously created volumes work as intended.

   You can change the state volume-mount prefix by updating the --statevolmountprefix=/path/to/dir argument in the mapr-kdfprovisioner image of the CSI driver yaml.

   NOTE

   The directory you specify needs to be read-writable for all users who provision volumes on the Data Fabric cluster using CSI drivers:

   # Create state volume mount path
   hadoop fs -mkdir /apps/k8s
   hadoop fs -chmod 777 /apps/k8s
   
   # Update csi driver yaml
   --statevolmountprefix=/apps/k8s

7. Understand the number of volume mounts per node that your application requires. The CSI driver default is 20 volume mounts per node. You can modify the number of volume mounts per node by adjusting the value of the maxvolumepernode parameter in the csi-maprkdf-<version>.yaml or csi-maprnfskdf-<version>.yaml file.