OpenShift 4 - 用容器提升MySQL的可用性

在容器中部署MySQL

1. 創建mysql項目

$ oc new-project mysql

2. 登錄OpenShift控制檯，進入Developer視圖，然後在左側菜單中進入“+Add”，在右側點擊Database。
   
3. 在Developer Catalog頁面中進入Database的MySQL分類，然後點擊進入MySQL。
   
4. 在右滑的頁面中點擊Instantiate Template按鈕。
   
5. 提供MySQL所需要的用戶名和密碼，然後點擊Create。
   
6. 執行命令，查看OpenShift創建的對象狀態。成功後應該有1個Pod在運行。

$ oc get all
NAME                 READY   STATUS      RESTARTS   AGE
pod/mysql-1-922n9    1/1     Running     0          8h
pod/mysql-1-deploy   0/1     Completed   0          8h
 
NAME                            DESIRED   CURRENT   READY   AGE
replicationcontroller/mysql-1   1         1         1       8h
 
NAME            TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
service/mysql   ClusterIP   172.30.153.211   <none>        3306/TCP   8h
 
NAME                                       REVISION   DESIRED   CURRENT   TRIGGERED BY
deploymentconfig.apps.openshift.io/mysql   1          1         1         config,image(mysql:8.0)

驗證容器化MySQL的可用性

1. 執行命令，用上一步的Pod名稱進入該Pod的容器中。

$ oc rsh mysql-1-922n9
sh-4.2$

2. 登錄MySQL。

sh-4.2$ mysql -uadmin -ppassword

3. 查看目前已有的數據庫，然後切換到sampledb數據庫環境中

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| sampledb           |
+--------------------+
2 rows in set (0.00 sec)
 
mysql> use sampledb;
Database changed

4. 創建一個測試表，然後插入一些測試數據。

mysql> create table test (name char(10));
Query OK, 0 rows affected (0.02 sec)
 
mysql> insert into test value ('Tom');
Query OK, 1 row affected (0.01 sec)
 
mysql> insert into test value ('Jobs');
Query OK, 1 row affected (0.00 sec)
 
mysql> insert into test value ('Bill');
Query OK, 1 row affected (0.00 sec)
 
mysql> select * from test;
+------+
| name |
+------+
| Tom  |
| Jobs |
| Bill |
+------+
3 rows in set (0.00 sec)

5. 刪除運行MySQL的Pod，然後確認OpenShift會自動創建一個新的Pod實例運行MySQL。

$ oc delete pod mysql-1-922n9
pod "mysql-1-922n9" deleted
$ oc get pod
NAME             READY   STATUS      RESTARTS   AGE
mysql-1-deploy   0/1     Completed   0          9h
mysql-1-xpczm    1/1     Running     0          7s

6. 再次進入運行MySQL的Pod。

$ oc rsh mysql-1-xpczm 
sh-4.2$

7. 然後查看在sampledb數據庫中以前創建的test表。

sh-4.2$ mysql -uadmin -ppassword
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 75
Server version: 8.0.17 Source distribution
 
Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
 
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
 
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
 
mysql> use sampledb;
Database changed
mysql> select * from test;
+------+
| name |
+------+
| Tom  |
| Jobs |
| Bill |
+------+
3 rows in set (0.00 sec)