基于CentOS 8实现MHA实战案例

1. 在管理节点上安装两个包(不支持centos8，只支持CentOS7 以下版本),mha4MySQL-manager 
   mha4mysql-node
2. 在被管理节点安装（支持CentOS 8，7，6）mha4mysql-node
3. 在管理节点建立配置文件mkdir /etc/mastermha/
   vim /etc/mastermha/App1.cnf 
   [server default]
   user=mhauser
   password=magedu
   manager_workdir=/data/mastermha/app1/
   manager_log=/data/mastermha/app1/manager.log
   remote_workdir=/data/mastermha/app1/
   ssh_user=root
   repl_user=repluser
   repl_password=magedu
   ping_interval=1
   [server1]
   hostname=192.168.8.17
   candidate_master=1
   [server2]
   hostname=192.168.8.27
   candidate_master=1
   [server3]
   hostname=192.168.8.37
4. 实现Mastervim /etc/my.cnf
   [mysqld]
   log-bin
   server_id=1
   skip_name_resolve=1
   mysql>show master logs
   mysql>grant replication slave on *.* to repluser@'192.168.8.%' identified by 'magedu';
   mysql>grant all on *.* to mhauser@'192.168.8.%' identified by 'magedu';
5. 实现slavevim /etc/my.cnf
   [mysqld]
   server_id=2 #不同节点此值各不相同
   log-bin
   read_only
   relay_log_purge=0
   skip_name_resolve=1
   ​
   mysql>CHANGE MASTER TO MASTER_HOST=‘MASTER_IP', MASTER_USER='repluser', MASTER_PASSWORD=‘magedu', MASTER_LOG_FILE='mariadb-bin.000001', MASTER_LOG_POS=245;
6. 在所有节点实现相互之间ssh key验证

过程略

7. Mha验证和启动masterha_check_ssh --conf=/etc/mastermha/app1.cnf
   masterha_check_repl --conf=/etc/mastermha/app1.cnf
   masterha_manager --conf=/etc/mastermha/app1.cnf
8. 排错日志：/data/mastermha/app1/manager.log