[Doc] update change_root_password_howto.md (#295)

Signed-off-by: yandongxiao <[email protected]>

doc/change_root_password_howto.md

@@ -11,25 +11,36 @@ password chosen for the root.
 
 **A StarRocks cluster is deployed and up with empty root password by the operator.**
 
-## Steps to Change the Password For root User
+## 1. Change the password for root user
 
-1. connect to starRocks FE with mysql client, and change the root user password.
-    ```SQL
-    mysql -h <FE_IP/FE_SERVICE> -P 9030 -u root
+Connect to StarRocks FE with a MySQL client and change the root user password.
 
-    # change root password to `mysql_password`
-    MySQL [(none)]> SET PASSWORD = PASSWORD('mysql_password');
-    ```
+```SQL
+mysql
+-h <FE_IP/FE_SERVICE> -P 9030 -u root
 
-2. create a secret **rootcredential** with the key **password** to store the root password
+# change root password to `mysql_password`
+MySQL [(none)]> SET PASSWORD = PASSWORD('mysql_password');
+```
+
+## 2. Inject MYSQL_PWD environment variable to StarRocks components
+
+There are two ways to deploy StarRocks cluster:
+
+1. Deploy StarRocks cluster with `StarRocksCluster` CR yaml.
+2. Deploy StarRocks cluster with Helm chart.
+
+Therefore, there are two ways to inject the MYSQL_PWD environment variable into StarRocks components.
+
+### 2.1 inject MYSQL_PWD environment variable with StarRocksCluster CRD yaml
+
+1. Create a secret **rootcredential** with the key **password** to store the root password
 
    ```shell
    kubectl create secret generic rootcredential --from-literal=password=mysql_password
    ```
 
-3. Update StarRocks crd yaml
-
-   Add the following snippets to `starRocksFeSpec/starRocksBeSpec/starRocksCnSpec` respectively if the corresponding
+2. Add the following snippets to `starRocksFeSpec/starRocksBeSpec/starRocksCnSpec` respectively if the corresponding
    components are deployed.
 
    ```yaml
@@ -58,18 +69,98 @@ password chosen for the root.
          key: password
    ```
 
-4. Apply the crd yaml
+3. Apply the crd yaml
 
    ```shell
    kubectl apply -f <crd_yaml>
    ```
 
-   It will trigger a rolling restart of the cluster, wait until the cluster restart completed.
-
-5. Verify the password is all set
-
-   After the pods are restarted, run the following command to check the correctness of the password.
-
-   ``` shell
-   kubectl exec <podName> -- sh -c 'echo $MYSQL_PWD'
-   ```
+It will trigger a rolling restart of the cluster, wait until the cluster restart completed.
+
+### 2.2 Inject MYSQL_PWD environment variable with helm chart
+
+If you are using the `kube-starrocks` Helm chart, add the following snippets to `values.yaml`.
+
+```yaml
+
+starrocks:
+  # create secrets if necessary.
+  secrets:
+    - name: rootcredential
+      data:
+        password: mysql_password
+
+  starrocksFESpec:
+    feEnvVars:
+      - name: "MYSQL_PWD"
+        valueFrom:
+          secretKeyRef:
+            name: rootcredential
+            key: password
+
+  starrocksBeSpec:
+    beEnvVars:
+      - name: "MYSQL_PWD"
+        valueFrom:
+          secretKeyRef:
+            name: rootcredential
+            key: password
+
+  starrocksCnSpec:
+    cnEnvVars:
+      - name: "MYSQL_PWD"
+        valueFrom:
+          secretKeyRef:
+            name: rootcredential
+            key: password
+```
+
+If you are using the `starrocks` Helm chart, add the following snippets to `values.yaml`.
+
+```yaml
+# create secrets if necessary.
+secrets:
+- name: rootcredential
+  data:
+    password: mysql_password
+
+starrocksFESpec:
+  feEnvVars:
+  - name: "MYSQL_PWD"
+    valueFrom:
+      secretKeyRef:
+        name: rootcredential
+        key: password
+
+starrocksBeSpec:
+  beEnvVars:
+  - name: "MYSQL_PWD"
+    valueFrom:
+      secretKeyRef:
+        name: rootcredential
+        key: password
+
+starrocksCnSpec:
+  cnEnvVars:
+  - name: "MYSQL_PWD"
+    valueFrom:
+      secretKeyRef:
+        name: rootcredential
+        key: password
+```
+
+Run the following command to upgrade the cluster.
+
+```shell
+helm upgrade <release_name> <chart_path> -f values.yaml
+```
+
+It will trigger a rolling restart of the cluster, wait until the cluster restart completed.
+
+## 3. Verify the password is all set
+
+After the pods are restarted, run the following command to check the correctness of the password.
+
+``` shell
+kubectl exec <podName> -- sh -c 'echo $MYSQL_PWD'
+```