[cinder-csi-plugin] Add example for generic epehemeral support (kubernetes#1594)

Author: ramineni

docs/cinder-csi-plugin/examples.md

@@ -102,14 +102,14 @@ index.html  lost+found
 
 ## Deploy app using Inline volumes
 
-Sample App definition on using Inline volumes can be found at [here](../../examples/cinder-csi-plugin/inline/inline-example.yaml)
+Sample App definition on using Inline volumes can be found at [here](../../examples/cinder-csi-plugin/ephemeral/csi-ephemeral-volumes-example.yaml)
 
 Prerequisites:
 * Deploy CSI Driver, with both volumeLifecycleModes enabled as specified [here](../../manifests/cinder-csi-plugin/csi-cinder-driver.yaml)
 
 Create a pod with inline volume
 ```
-$ kubectl create -f examples/cinder-csi-plugin/inline/inline-example.yaml
+$ kubectl create -f examples/cinder-csi-plugin/ephemeral/csi-ephemeral-volumes-example.yaml
 ```
 Get the pod description, verify created volume in Volumes section.
 ```

docs/cinder-csi-plugin/features.md

@@ -66,7 +66,11 @@ This feature enables creating volume snapshots and restore volume from snapshot.
 * To avail the feature. deploy the snapshot-controller and CRDs as part of their Kubernetes cluster management process (independent of any CSI Driver) . For more info, refer [Snapshot Controller](https://kubernetes-csi.github.io/docs/snapshot-controller.html)
 * For example on using snapshot feature, refer [sample app](./examples#snapshot-create-and-restore)
 
-## Inline Volumes
+## Ephemeral Volumes
+
+Two different Kubernetes features allow volumes to follow the Pod's lifecycle: CSI Ephemeral Volumes and Generic Ephemeral Volumes
+
+### CSI Ephemeral Volumes
 
 This feature allows CSI volumes to be directly embedded in the Pod specification instead of a PersistentVolume. Volumes specified in this way are ephemeral and do not persist across Pod restarts.
 
@@ -75,6 +79,12 @@ This feature allows CSI volumes to be directly embedded in the Pod specification
 * `podInfoOnMount` must be `true` to use this feature.
 * For usage, refer [sample app](./examples.md#deploy-app-using-inline-volumes)
 
+### Generic Ephemeral Volumes
+
+As of Kubernetes v1.21, this is beta feature and enabled by default.
+
+The key design idea is that the parameters for a volume claim are allowed inside a volume source of the Pod. For sample app, refer [here](../../examples/cinder-csi-plugin/ephemeral/generic-ephemeral-volumes.yaml)
+
 ## Volume Cloning
 
 This feature enables cloning a volume from existing PVCs in Kubernetes. As of Kubernetes v1.16, volume cloning is beta feature and enabled by default.

docs/cinder-csi-plugin/using-cinder-csi-plugin.md

@@ -228,7 +228,7 @@ helm install --namespace kube-system --name cinder-csi ./charts/cinder-csi-plugi
 * [Volume Expansion](./features.md#volume-expansion)
 * [Volume Cloning](./features.md#volume-cloning)
 * [Volume Snapshots](./features.md#volume-snapshots)
-* [Inline Volumes](./features.md#inline-volumes)
+* [Ephemeral Volumes](./features.md#inline-volumes)
 * [Multiattach Volumes](./features.md#multi-attach-volumes)
 * [Liveness probe](./features.md#liveness-probe)
 

examples/cinder-csi-plugin/inline/inline-example.yaml renamed to examples/cinder-csi-plugin/ephemeral/csi-ephemeral-volumes-example.yaml

@@ -0,0 +1,32 @@
+apiVersion: storage.k8s.io/v1
+kind: StorageClass
+metadata:
+  name: scratch-storage-class 
+provisioner: cinder.csi.openstack.org
+
+---
+apiVersion: v1
+kind: Pod
+metadata:
+  name: ephemeral-example
+spec:
+  containers:
+  - image: nginx
+    imagePullPolicy: IfNotPresent
+    name: nginx-inline
+    volumeMounts:
+    - name: scratch-volume
+      mountPath: /var/lib/www/html
+  volumes:
+  - name: scratch-volume
+    ephemeral:
+      volumeClaimTemplate:
+        metadata:
+          labels:
+            type: my-frontend-volume
+        spec:
+          accessModes: [ "ReadWriteOnce" ]
+          storageClassName: scratch-storage-class
+          resources:
+            requests:
+              storage: 1Gi