## 模块 1: 创建用户和角色

### 步骤 1：登录远程 Linux

+ 点击这里 - [终端 1](ssh://monitor1-ssh#1) 打开一个新的终端，连接到为你的实践实验分配的虚拟机。

### 步骤 2. 连接到 TiDB

  ```bash
  mysql -h ${HOST_DB1_PRIVATE_IP} --port 4000 -u root
  ```

### 步骤 3. 创建用户 `jack`

+ 创建一个名为 `'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}'`的新用户。

  ```sql
  CREATE USER 'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}' IDENTIFIED BY 'pingcap';
  ```

  ```output
  tidb> CREATE USER 'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}' IDENTIFIED BY 'pingcap';
  Query OK, 0 rows affected (0.03 sec)
  ```

### 步骤 4. 创建新角色

+ 创建两个名为 `r_manager` 和 `r_staff` 的新角色。

  ```sql
  CREATE ROLE r_manager, r_staff;
  ```

  ```output
  tidb> CREATE ROLE r_manager, r_staff;
  Query OK, 0 rows affected (0.02 sec)
  ```

### 步骤 5. 查看用户和角色

  ```sql
  SELECT user, host, authentication_string FROM mysql.user\G
  ```

  ```output
  tidb> SELECT user, host, authentication_string FROM mysql.user\G
  *************************** 1. row ***************************
                    user: root
                    host: %
  authentication_string: *7451D85E369BF796CD15900AF9BFE0D5D920716E
  *************************** 2. row ***************************
                    user: jack
                    host: 172.31.0.106
  authentication_string: *926E4B88EB93FD344DF0870EE025D6EB153C02DE
  *************************** 3. row ***************************
                    user: r_manager
                    host: %
  authentication_string:
  *************************** 4. row ***************************
                    user: r_staff
                    host: %
  authentication_string:
  4 rows in set (0.00 sec)
  ```

+ 用户和角色都存储在 `mysql.user` 表中。角色没有密码。

### 步骤 6. 查看 `r_staff`

  ```sql
  SELECT * FROM mysql.user WHERE user='r_staff'\G
  ```

  ```output
  tidb> SELECT * FROM mysql.user WHERE user='r_staff'\G
  *************************** 1. row ***************************
                    Host: %
                    User: r_staff
   authentication_string:
                  plugin: mysql_native_password
             Select_priv: N
             Insert_priv: N
             Update_priv: N
             Delete_priv: N
             Create_priv: N
               Drop_priv: N
               ...
              Event_priv: N
         Repl_slave_priv: N
        Repl_client_priv: N
            Trigger_priv: N
        Create_role_priv: N
          Drop_role_priv: N
          Account_locked: Y
           Shutdown_priv: N
             Reload_priv: N
               FILE_priv: N
             Config_priv: N
  Create_Tablespace_Priv: N
  1 row in set (0.00 sec)
  ```

### 步骤 7. 修改 `jack` 的密码

+ 使用 `ALTER USER` 语句将 `'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}'` 的密码更改为 `tidb` ，然后退出会话。请手动 `${HOST_MONITOR1_PRIVATE_IP}` 替换为真实 IP。

  ```sql
  ALTER USER 'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}' IDENTIFIED BY 'tidb';
  ```

  ```output
  tidb> ALTER USER 'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}' IDENTIFIED BY 'tidb';
  Query OK, 0 rows affected (0.02 sec)
  ```

  ```sql
  EXIT;
  ```

  ```output
  tidb> EXIT
  Bye
  ```

### 步骤 8. 以 `jack` 身份连接到 TiDB

+ 使用新密码以 `'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}’` 用户身份连接到 TiDB，然后退出会话。

  ```bash
  mysql -h ${HOST_DB1_PRIVATE_IP} -P 4000 -ujack -ptidb
  ```

  ```sql
  EXIT
  ```

  ```output
  tidb> EXIT
  Bye
  ```

### 步骤 9. 以 `root` 身份连接到 TiDB

  ```bash
  mysql -h ${HOST_DB1_PRIVATE_IP} --port 4000 -u root
  ```

### 步骤 10. 删除 `r_staff`

  ```sql
  DROP ROLE r_staff;
  ```

  ```output
  tidb> DROP ROLE r_staff;
  Query OK, 0 rows affected (0.03 sec)
  ```

  ```sql
  SELECT user, host FROM mysql.user WHERE user='r_staff';
  ```

  ```output
  tidb> SELECT user, host FROM mysql.user WHERE user='r_staff';
  Empty set (0.01 sec)
  ```

### 步骤 11. 删除 `r_manager`

  ```sql
  DROP ROLE r_manager;
  ```

  ```output
  tidb> DROP ROLE r_manager;
  Query OK, 0 rows affected (0.03 sec)
  ```

  ```sql
  SELECT user, host FROM mysql.user WHERE user='r_manager';
  ```

  ```output
  tidb> SELECT user, host FROM mysql.user WHERE user='r_manager';
  Empty set (0.01 sec)
  ```

### 步骤 12. 删除用户 `jack`

+ 使用 `DROP USER` 语句删除 `'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}’`  用户。

  ```sql
  DROP USER 'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}';
  ```

  ```output
  tidb> DROP USER 'jack'@'${LAB:HOST_MONITOR1_PRIVATE_IP}';
  Query OK, 0 rows affected (0.02 sec)
  ```

  ```sql
  SELECT user, host FROM mysql.user WHERE user='jack';
  ```

  ```output
  tidb> SELECT user, host FROM mysql.user WHERE user='jack';
  Empty set (0.00 sec)
  ```

  ```sql
  EXIT
  ```

  ```output
  tidb> EXIT
  Bye
  ```