HDDS-14311. [Website v2] [Docs] [User Guide] CSI Protocol (#197)

Co-authored-by: Wei-Chiu Chuang <weichiu@apache.org>

Author: echonesis

cspell.yaml

@@ -135,6 +135,7 @@ words:
 - Boto3
 - fsspec
 - libhdfs
+- goofys
 - WebHDFS
 # Misc words
 - acking

docs/04-user-guide/01-client-interfaces/08-csi-protocol.md

@@ -0,0 +1,73 @@
+---
+sidebar_label: CSI Protocol
+---
+
+# CSI Protocol
+
+:::warning
+Ozone CSI support is still in alpha phase and buckets can be mounted only via 3rd party S3 compatible Fuse implementation (like Goofys).
+Fuse over S3 can provide only limited performance compared to a native Fuse file system.
+Long-term Ozone may support a custom solution to mount buckets which provides better user experience (with fuse or NFS or any other solution).
+Until that CSI is recommended to use only if you can live with this limitation and your use case is tested carefully.
+:::
+
+`Container Storage Interface` (CSI) will enable storage vendors (SP) to develop a plugin once and have it work across a number of container orchestration (CO) systems like Kubernetes or Yarn.
+
+To get more information about CSI at [SCI spec](https://github.com/container-storage-interface/spec/blob/master/spec.md)
+
+CSI defined a simple gRPC interface with 3 interfaces (Identity, Controller, Node). It defined how the Container Orchestrator can request the creation of a new storage space or the mount of the newly created storage but doesn't define how the storage can be mounted.
+
+![CSI](CSI.png)
+
+By default Ozone CSI service uses a S3 fuse driver ([goofys](https://github.com/kahing/goofys)) to mount the created Ozone bucket. Implementation of other mounting options such as a dedicated NFS server or native Fuse driver is work in progress.
+
+Ozone CSI is an implementation of CSI, it can make possible of using Ozone as a storage volume for a container.
+
+## Getting started
+
+First of all, we need an Ozone cluster with s3gateway, and its OM RPC port and s3gateway port must be visible to CSI pod,
+because CSIServer will access OM to create or delete a bucket, also, CSIServer will publish volume by creating a mount point to s3g
+through goofys.
+
+If you don't have an Ozone cluster on Kubernetes, you can reference [Kubernetes](../../02-quick-start/01-installation/02-kubernetes.md) to create one. Use the resources from `kubernetes/examples/ozone` where you can find all the required Kubernetes resources to run cluster together with the dedicated Ozone CSI daemon (check `kubernetes/examples/ozone/csi`)
+
+Now, create the CSI related resources by execute the follow command.
+
+```bash
+kubectl create -f /ozone/kubernetes/examples/ozone/csi
+```
+
+## Create pv-test and visit the result
+
+Create pv-test related resources by execute the follow command.
+
+```bash
+kubectl create -f /ozone/kubernetes/examples/ozone/pv-test
+```
+
+Attach the pod `scm-0` and put a key into the `/s3v/pvc*` bucket.
+
+```bash
+kubectl exec -it  scm-0  bash
+[hadoop@scm-0 ~]$ ozone sh bucket list s3v
+[ {
+  "metadata" : { },
+  "volumeName" : "s3v",
+  "name" : "pvc-861e2d8b-2232-4cd1-b43c-c0c26697ab6b",
+  "storageType" : "DISK",
+  "versioning" : false,
+  "creationTime" : "2020-06-11T08:19:47.469Z",
+  "encryptionKeyName" : null
+} ]
+[hadoop@scm-0 ~]$ ozone sh key put /s3v/pvc-861e2d8b-2232-4cd1-b43c-c0c26697ab6b/A LICENSE.txt
+```
+
+Now, let's forward port of the `ozone-csi-test-webserver-7cbdc5d65c-h5mnn` to see the UI through the web browser.
+
+```bash
+kubectl port-forward ozone-csi-test-webserver-7cbdc5d65c-h5mnn 8000:8000
+```
+
+Eventually, we can see the result from `http://localhost:8000/`
+
+![persistent-volume-test-web-ui](./persistent-volume-test-web-ui.png)