MHA 搭建网上的教程比较多,不做赘述。参考：http://www.cnblogs.com/gomysql/p/3675429.html
环境安装：centos7 搭建 MHA
安装manger节点是需要安装依赖包，如果根据报错提示缺少的包名单独下载，安装失败的可能性比较大（教训总结）
错误1：
[root@localhost ~]# yum -y install mha4mysql-manager-0.58-0.el7.centos.noarch.rpm
Loaded plugins: fastestmirror
Repository base is listed more than once in the configuration
Repository updates is listed more than once in the configuration
Repository extras is listed more than once in the configuration
Repository centosplus is listed more than once in the configuration
Examining mha4mysql-manager-0.58-0.el7.centos.noarch.rpm: mha4mysql-manager-0.58-0.el7.centos.noarch
Marking mha4mysql-manager-0.58-0.el7.centos.noarch.rpm to be installed
Resolving Dependencies
--> Running transaction check
---> Package mha4mysql-manager.noarch 0:0.58-0.el7.centos will be installed
--> Processing Dependency: perl(Log::Dispatch) for package: mha4mysql-manager-0.58-0.el7.centos.noarch
Loading mirror speeds from cached hostfile
* base: mirror.bit.edu.cn
* extras: mirror.bit.edu.cn
* updates: mirror.bit.edu.cn
--> Processing Dependency: perl(Log::Dispatch) for package: mha4mysql-manager-0.58-0.el7.centos.noarch
--> Processing Dependency: perl(Log::Dispatch::File) for package: mha4mysql-manager-0.58-0.el7.centos.noarch
--> Processing Dependency: perl(Log::Dispatch::Screen) for package: mha4mysql-manager-0.58-0.el7.centos.noarch
--> Finished Dependency Resolution
Error: Package: mha4mysql-manager-0.58-0.el7.centos.noarch (/mha4mysql-manager-0.58-0.el7.centos.noarch)
Requires: perl(Log::Dispatch)
Error: Package: mha4mysql-manager-0.58-0.el7.centos.noarch (/mha4mysql-manager-0.58-0.el7.centos.noarch)
Requires: perl(Log::Dispatch::File)
Error: Package: mha4mysql-manager-0.58-0.el7.centos.noarch (/mha4mysql-manager-0.58-0.el7.centos.noarch)
Requires: perl(Log::Dispatch::Screen)
You could try using --skip-broken to work around the problem
You could try running: rpm -Va --nofiles --nodigest解决：
1、Download the latest epel-release rpm from 下载安装yum源
http://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
2、Install epel-release rpm:
rpm -Uvh epel-release*rpm
3、Install perl-Log-Dispatch rpm package:
yum install mha4mysql-manager-0.58-0.el7.centos.noarch.rpm -y
此方法使用所有perl依赖包报错。:
1、安装
yum -y install mha4mysql-node-0.58-0.el7.centos.noarch.rpm
yum -y install mha4mysql-manager-0.58-0.el7.centos.noarch.rpm
错误2：
[root@master mha4mysql]# masterha_check_ssh --conf=/etc/mha4mysql/app1.cnf
Fri Mar 30 17:49:06 2018 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Fri Mar 30 17:49:06 2018 - [info] Reading application default configuration from /etc/mha4mysql/app1.cnf..
Parameter ping_interval must be positive integer! current value: 1 #设置监控主库，发送ping包的时间间隔，默认是3秒，尝试三次没有回应的时候自动进行railover
at /usr/share/perl5/vendor_perl/MHA/SSHCheck.pm line 148.解决：
/etc/mha4mysql/app1.cnf文件参数后面不能有空格
错误3：
[root@master ~]# masterha_check_ssh --conf=/etc/mha4mysql/app1.cnf
Fri Mar 30 18:28:28 2018 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Fri Mar 30 18:28:28 2018 - [info] Reading application default configuration from /etc/mha4mysql/app1.cnf..
Fri Mar 30 18:28:28 2018 - [info] Reading server configuration from /etc/mha4mysql/app1.cnf..
Fri Mar 30 18:28:28 2018 - [info] Starting SSH connection tests..
Fri Mar 30 18:28:28 2018 - [error][/usr/share/perl5/vendor_perl/MHA/SSHCheck.pm, ln63]
Fri Mar 30 18:28:28 2018 - [debug] Connecting via SSH from root@192.168.31.16(192.168.31.16:22) to root@192.168.31.118(192.168.31.118:22)..
Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).
Fri Mar 30 18:28:28 2018 - [error][/usr/share/perl5/vendor_perl/MHA/SSHCheck.pm, ln111] SSH connection from root@192.168.31.16(192.168.31.16:22) to root@192.168.31.118(192.168.31.118:22) failed!
Fri Mar 30 18:28:29 2018 - [debug]
Fri Mar 30 18:28:28 2018 - [debug] Connecting via SSH from root@192.168.31.118(192.168.31.118:22) to root@192.168.31.16(192.168.31.16:22)..
Fri Mar 30 18:28:29 2018 - [debug] ok.
Fri Mar 30 18:28:29 2018 - [debug] Connecting via SSH from root@192.168.31.118(192.168.31.118:22) to root@192.168.31.2(192.168.31.2:22)..
Fri Mar 30 18:28:29 2018 - [debug] ok.
Fri Mar 30 18:28:30 2018 - [debug]
Fri Mar 30 18:28:29 2018 - [debug] Connecting via SSH from root@192.168.31.2(192.168.31.2:22) to root@192.168.31.16(192.168.31.16:22)..
Fri Mar 30 18:28:29 2018 - [debug] ok.
Fri Mar 30 18:28:29 2018 - [debug] Connecting via SSH from root@192.168.31.2(192.168.31.2:22) to root@192.168.31.118(192.168.31.118:22)..
Fri Mar 30 18:28:30 2018 - [debug] ok.
SSH Configuration Check Failed!
at /usr/bin/masterha_check_ssh line 44.
[root@master ~]# ssh master
root@master's password:
Permission denied, please try again.
root@master's password:
Permission denied, please try again.
root@master's password:
Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).
[root@master ~]#
[root@master ~]#
[root@master ~]# vim /etc/mha4mysql/app1.cnf
[root@master ~]# masterha_check_ssh --conf=/etc/mha4mysql/app1.cnf
Fri Mar 30 18:41:21 2018 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Fri Mar 30 18:41:21 2018 - [info] Reading application default configuration from /etc/mha4mysql/app1.cnf..
Fri Mar 30 18:41:21 2018 - [info] Reading server configuration from /etc/mha4mysql/app1.cnf..
Fri Mar 30 18:41:21 2018 - [info] Starting SSH connection tests..
Fri Mar 30 18:41:22 2018 - [debug]
Fri Mar 30 18:41:21 2018 - [debug] Connecting via SSH from root@192.168.31.118(192.168.31.118:22) to root@192.168.31.2(192.168.31.2:22)..
Fri Mar 30 18:41:22 2018 - [debug] ok.
Fri Mar 30 18:41:22 2018 - [debug]
Fri Mar 30 18:41:22 2018 - [debug] Connecting via SSH from root@192.168.31.2(192.168.31.2:22) to root@192.168.31.118(192.168.31.118:22)..
Fri Mar 30 18:41:22 2018 - [debug] ok.
Fri Mar 30 18:41:22 2018 - [info] All SSH connection tests passed successfully.解决方法：
/etc/mha4mysql/app1.cnf
注释掉manager管理节点
错误4：
[root@localhost ~]# masterha_check_repl --conf=/etc/app1.cnf
Sun Apr 22 20:29:30 2018 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Sun Apr 22 20:29:30 2018 - [info] Reading application default configuration from /etc/app1.cnf..
Sun Apr 22 20:29:30 2018 - [info] Reading server configuration from /etc/app1.cnf..
Sun Apr 22 20:29:30 2018 - [info] MHA::MasterMonitor version 0.58.
Sun Apr 22 20:29:32 2018 - [error][/usr/share/perl5/vendor_perl/MHA/ServerManager.pm, ln193] There is no alive slave. We can't do failover
Sun Apr 22 20:29:32 2018 - [error][/usr/share/perl5/vendor_perl/MHA/MasterMonitor.pm, ln427] Error happened on checking configurations. at /usr/share/perl5/vendor_perl/MHA/MasterMonitor.pm line 329.
Sun Apr 22 20:29:32 2018 - [error][/usr/share/perl5/vendor_perl/MHA/MasterMonitor.pm, ln525] Error happened on monitoring servers.
Sun Apr 22 20:29:32 2018 - [info] Got exit code 1 (Not master dead).
MySQL Replication Health is NOT OK!解决方法:
(1).删除健康检查文件 rm -rf /var/log/masterha/app1/app1.master_status.health
(2).在宕机的数据库中重新同步到主服务器 change master to master_host……………
(3).检查复制是否出错 masterha_check_repl –conf=/etc/mysqlmha/conf/app1.cnf
或者
(1).检查防火墙