Container Storage Interface (CSI)

• CNI allows multiple storage solutions be compatible with Kubernetes
• Allows any container orchestration tool to work with any storage vendor with supported plugin

• It defines a set of RPCs called by the container orchestrator and must be implemented by the storage drivers

• CreateVolume: Call (provision new volume) -> Should (provision new volume on the storage)

• DeleteVolume: Call (delete volume) -> Should (decommission a volume)
• ControllerPublishVolume: Call (place workload that uses volume onto a node) -> Should (make volume available on a node)

CSI Snapshotter

• https://github.com/kubernetes-csi/external-snapshotter

• The CSI snapshotter is part of Kubernetes implementation of Container Storage Interface (CSI) and implements both the volume snapshot and the volume group snapshot feature.

• Example: https://github.com/kubernetes-sigs/aws-ebs-csi-driver/tree/master/examples/kubernetes/snapshot

apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshotClass
metadata:
  name: csi-aws-vsc
driver: ebs.csi.aws.com
deletionPolicy: Delete

apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshot
metadata:
  name: ebs-volume-snapshot
spec:
  volumeSnapshotClassName: csi-aws-vsc
  source:
    persistentVolumeClaimName: ebs-claim

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: ebs-snapshot-restored-claim
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: ebs-sc
  resources:
    requests:
      storage: 4Gi
  dataSource:
    name: ebs-volume-snapshot
    kind: VolumeSnapshot
    apiGroup: snapshot.storage.k8s.io