CSI ephemeral volume alpha documentation (#15055)

content/en/docs/concepts/storage/volumes.md

@@ -1313,6 +1313,43 @@ feature gates which must be enabled for this feature are `BlockVolume` and
 Learn how to
 [setup your PV/PVC with raw block volume support](/docs/concepts/storage/persistent-volumes/#raw-block-volume-support).
 
+#### CSI ephemeral volumes
+
+{{< feature-state for_k8s_version="v1.15" state="alpha" >}}
+
+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.
+
+Example:
+
+```yaml
+kind: Pod
+apiVersion: v1
+metadata:
+  name: my-csi-app
+spec:
+  containers:
+    - name: my-frontend
+      image: busybox
+      volumeMounts:
+      - mountPath: "/data"
+        name: my-csi-inline-vol
+      command: [ "sleep", "1000000" ]
+  volumes:
+    - name: my-csi-inline-vol
+      csi:
+        driver: inline.storage.kubernetes.io
+        volumeAttributes:
+              foo: bar
+```
+
+This feature requires CSIInlineVolume feature gate to be enabled:
+
+```
+--feature-gates=CSIInlineVolume=true
+```
+
+CSI ephemeral volumes are only supported by a subset of CSI drivers. Please see the list of CSI drivers [here](https://kubernetes-csi.github.io/docs/drivers.html).
+
 # Developer resources
 For more information on how to develop a CSI driver, refer to the [kubernetes-csi
 documentation](https://kubernetes-csi.github.io/docs/)