MHA切换过程:

1.监测master的状态Ping(SELECT) succeeded, waiting until MySQL doesn't respond..
2.当监控发现master异常时发出warning，并重试4次连接查询，并同时检查SSH状态。
3.读取配置文件，检查其他节点状态。
Reading configuration file /etc/masterha/masterha_default.conf and /etc/masterha/app1.conf again, and trying to connect to all servers to check server status..
经过双一轮检查，宣部master is down!

4.终止监控脚本Terminating monitoring script.
5.进入master failover进程：Starting master failover.（检查各节点状态，GTID based failover，Getting Latest Slaves Phase，）
Phase 1: Configuration Check Phase completed.
Phase 2: Dead Master Shutdown Phase completed.
Phase 3: Master Recovery Phase
Phase 3.1: Getting Latest Slaves Phase

Phase 3.3: Determining New Master Phase.

Phase 3.3: New Master Recovery Phase..(其实应该是3.4)

告知新节点环境binlog和position 并把new master 设置为Set read_only=0 on the new master.
完成master 迁移后,实现VIP迁移
Phase 4: Slaves Recovery Phase
Phase 4.1: Starting Slaves in parallel..

6.输出迁移报告:
----- Failover Report -----