OpenShift 4 - 用容器提升MySQL的可用性

在容器中部署MySQL

1. 创建mysql项目

$ oc new-project mysql

2. 登录OpenShift控制台，进入Developer视图，然后在左侧菜单中进入“+Add”，在右侧点击Database。
   
3. 在Developer Catalog页面中进入Database的MySQL分类，然后点击进入MySQL。
   
4. 在右滑的页面中点击Instantiate Template按钮。
   
5. 提供MySQL所需要的用户名和密码，然后点击Create。
   
6. 执行命令，查看OpenShift创建的对象状态。成功后应该有1个Pod在运行。

$ 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)

验证容器化MySQL的可用性

1. 执行命令，用上一步的Pod名称进入该Pod的容器中。

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

2. 登录MySQL。

sh-4.2$ mysql -uadmin -ppassword

3. 查看目前已有的数据库，然后切换到sampledb数据库环境中

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

4. 创建一个测试表，然后插入一些测试数据。

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. 删除运行MySQL的Pod，然后确认OpenShift会自动创建一个新的Pod实例运行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. 再次进入运行MySQL的Pod。

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

7. 然后查看在sampledb数据库中以前创建的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)