《童虎学习笔记》14分钟结合ProxySQL处理超半数MGR节点故障

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一、实战环境

Primary 节点(node1)	mysql 8.0.28	10.211.55.9
Secondary1 节点(node2)	mysql 8.0.28	10.211.55.4
Secondary2 节点(node3)	mysql 8.0.28	10.211.55.6
ProxySQL 节点(node4)	2.2.0	10.211.55.7

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二、模拟超半数节点故障

我们模拟MGR集群中2个Secondary节点都因故障停掉了

1、先干掉一个节点，手动杀掉node2上的mysqld服务

找到mysqld进程号后，进行kill

root@node2:~# ps aux|grep mysqld
root     1155011  0.0  0.0   2064  1412 pts/0    S    10:52   0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --user=mysql
mysql    1155290  1.3 28.6 1919508 581212 pts/0  Sl   10:52   0:01 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=node2.err --pid-file=node2.pid
root     1155950  0.0  0.0   5908   648 pts/0    S+   10:54   0:00 grep mysqld
root@node2:~# kill -9 1155011 1155290

2、查看MGR集群状态

可以看到node2的状态由ONLINE变为UNREACHABLE后在集群中消失了

mysql> select member_host, member_state, member_role from performance_schema.replication_group_members;
+-------------------+-----------------------+------------------+
| member_host | member_state     | member_role |
+-