add etcd docs

Signed-off-by: Hongliang Wang <hongliangwang@yunify.com>

content/en/docs/application-store/built-in-apps/etcd-app.md

@@ -0,0 +1,66 @@
+---
+title: "etcd App"
+keywords: 'kubernetes, kubesphere, etcd, app-store'
+description: 'How to use etcd'
+
+
+weight: 2240
+---
+
+# Objective
+
+This tutorial shows you how to quickly deploy an [etcd](https://etcd.io) application using templates from KubeSphere App Store (Powered by OpenPitrix). The demonstration includes importing application repository, sharing and deploying apps within a workspace.
+
+# Prerequisites
+
+- You have enabled [KubeSphere Application Store](/docs/pluggable-components/app-store/)
+- You have completed the tutorial [Create Workspace, Project, Account and Role](/docs/quick-start/create-workspace-and-project/). The account needs to be a platform regular user and to be invited as the project operator with the `operator` role. In this tutorial, we'll work in the project `apps` of the workspace `apps`.
+
+# Hands-on Lab
+
+## Step 1: Browse Apps
+
+1.1. Sign in KubeSphere as a workspace regular account (`apps-regular` for this guide), then enter into project `apps`.
+
+1.2. Click **Application Workloads → Applications**, click **Deploy New Application**.
+
+![Deploy App](/images/docs/appstore/etcd/deploy-app.png)
+
+1.3. Choose **From App Store**. Click `etcd`.
+
+![Deploy etcd](/images/docs/appstore/etcd/deploy-etcd.png)
+
+## Step 2: Deploy etcd Application
+
+2.1. Click **Deploy** at the top right, customize app name if needed, and then click **Next**.
+
+![Deploy etcd Info](/images/docs/appstore/etcd/deploy-etcd-info.png)
+
+2.2. Customize the persistent volume size, and then click **Deploy**.
+
+![etcd configuration](/images/docs/appstore/etcd/deploy-etcd-conf.png)
+
+2.3. Wait for a few minutes, then you will see the application showing `active` in the application list.
+
+![etcd Active](/images/docs/appstore/etcd/deploy-etcd-done.png)
+
+## Step 3: Access the etcd Service
+
+3.1. We can interact with etcd by etcdctl CLI tool within the etcd pod. Click the deployed app and enter the terminal.
+
+![etcd workload](/images/docs/appstore/etcd/access-etcd-workload.png)
+
+![etcd pod](/images/docs/appstore/etcd/access-etcd-pod.png)
+
+![etcd terminal](/images/docs/appstore/etcd/access-etcd-terminal.png)
+
+3.2. Write and read some data.
+
+```
+etcdctl set /name kubesphere
+etcdctl get /name
+```
+
+![etcd data](/images/docs/appstore/etcd/access-etcd-data.png)
+
+3.3. For clients within the KubeSphere cluster, etcd service can be accessed through `<app name>.<project name>.svc.<K8s domain>:2379` (`etcd-ca9w6t.apps.svc.cluster.local:2379` for this guide).