[root@node1 keepalived]# ip add|grep inet
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
inet 192.168.1.23/24 brd 192.168.1.255 scope global eth1
inet 192.168.1.27/32 scope global eth1:1
inet6 fe80::250:56ff:fe8d:496/64 scope link
备库服务器状态检查：
[root@node2 keepalived]# ip add|grep inet
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
inet 192.168.1.24/24 brd 192.168.1.255 scope global eth1
inet 192.168.1.27/32 scope global eth1:1
inet6 fe80::250:56ff:fe8d:3d1e/64 scope link
如果关掉从库的防火墙，那么VIP会选择高优先级的服务器上（priority）
此现象如何避免？我们可以在check_gateway.sh脚本里添加上组播状态检查的命令，我这里就不做了，仅做了网关检查的脑裂避免（网络问题导致网关暂时不可达而产生的脑裂）
6、模拟主切换到备后，主服务启动后是否会回切（优先级抢占测试）
（本次测试接着测试1进行，首先恢复主库的实例进程和keepalived进程）
主库执行命令：
[root@node1 keepalived]# service mysqld start
Starting MySQL (Percona Server)...... [ OK ]
[root@node1 keepalived]# service keepalived start
Starting keepalived: [ OK ]
[root@node1 keepalived]# service mysqld status
MySQL (Percona Server) running (1141) [ OK ]
[root@node1 keepalived]# service keepalived status
keepalived (pid 1230) is running...
[root@node1 keepalived]# ip add |grep inet
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
inet 192.168.1.23/24 brd 192.168.1.255 scope global eth1
inet6 fe80::250:56ff:fe8d:496/64 scope link
备库执行命令：
[root@node2 keepalived]# service keepalived status
keepalived (pid 12207) is running...
[root@node2 keepalived]# service mysqld status
MySQL (Percona Server) running (14146) [ OK ]
[root@node2 keepalived]# ip add |grep inet
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
inet 192.168.1.24/24 brd 192.168.1.255 scope global eth1
inet 192.168.1.27/32 scope global eth1:1
inet6 fe80::250:56ff:fe8d:3d1e/64 scope link
此时发现即使主库的服务恢复正常也不会主动抢占从库的VIP，因为两边设置的都是backup模式，但此时如果备库的服务、实例等原因导致需要切换VIP而此时主库由具备切换的条件，那么依旧可以完成切换（此时切记一旦完成主备切换后，需要手动恢复新的主备状态保障数据一致性后才能进行二次切换）
7、模拟备库数据延迟120S以上切换
从库先停止io_thread
(root:localhost:Sun May 20 10:24:45 2018)[(none)]>stop slave io_thread;
Query OK, 0 rows affected (0.00 sec)
主库做大量的数据变更操作
然后监控从库keepalived状态即可
8、模拟备库数据同步错误切换
从库状态：
[root@node2 keepalived]# mysql -uroot -e "show slave status \G"|egrep "Slave.*Running|Seconds_Behind_Master|Last_Errno"|grep -v "Slave_SQL_Running_State"
Slave_IO_Running: Yes
Slave_SQL_Running: No
Last_Errno: 1050
Seconds_Behind_Master: NULL
[root@node2 keepalived]# service keepalived status
keepalived is stopped
[root@node2 keepalived]# ip add |grep inet
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
inet 192.168.1.24/24 brd 192.168.1.255 scope global eth1
inet6 fe80::250:56ff:fe8d:3d1e/64 scope link
主库状态：
[root@node1 keepalived]# service mysqld status
MySQL (Percona Server) running (1141) [ OK ]
[root@node1 keepalived]# service keepalived status
keepalived (pid 1230) is running...
[root@node1 keepalived]# ip add |grep inet
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
inet 192.168.1.23/24 brd 192.168.1.255 scope global eth1
inet 192.168.1.27/32 scope global eth1:1
inet6 fe80::250:56ff:fe8d:496/64 scope link
此时如果主库相关服务宕机，是无法完成VIP切换，通过关闭mysqld服务测试