一：环境配置

192.168.78.128（备库，只读）， 192.168.78.129（主库），192.168.78.130（从库，master为128）

三台数据库可以SSH无密码登录

二：配置配置主从半同步

# 所有mysql数据库服务器，安装半同步插件(semisync_master.so,semisync_slave.so)

mysql> install plugin rpl_semi_sync_master soname 'semisync_master.so';

mysql> install plugin rpl_semi_sync_slave soname 'semisync_slave.so';  mysql> show variables like '%sync%';

# 查看半同步状态：

mysql> show status like '%sync%';

# 有几个状态参数值得关注的：

rpl_semi_sync_master_status：显示主服务是异步复制模式还是半同步复制模式

rpl_semi_sync_master_clients：显示有多少个从服务器配置为半同步复制模式

rpl_semi_sync_master_yes_tx：显示从服务器确认成功提交的数量

rpl_semi_sync_master_no_tx：显示从服务器确认不成功提交的数量

rpl_semi_sync_master_tx_avg_wait_time：事务因开启semi_sync，平均需要额外等待的时间

rpl_semi_sync_master_net_avg_wait_time：事务进入等待队列后，到网络平均等待时间

一般主从半同步需要修改配置文件，然后重启。最初安装如果用的是标配配置文件，通过set开启就可以了。

三：安装MHA

三台机器上都要做配置epel源

[root@M128 ~]#  rpm -ivh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm

安装所需要的包

[root@M128 ~]#  yum  -y install perl-DBD-MySQL perl-Config-Tiny perl-Log-Dispatch perl-Parallel-ForkManager perl-Config-IniFiles  ncftp perl-Params-Validate  perl-CPAN perl-Test-Mock-LWP.noarch perl-LWP-Authen-Negotiate.noarch perl-devel

[root@M128 ~]# yum -y install perl-ExtUtils-CBuilder perl-ExtUtils-MakeMaker  这个百度文档没有但是显然是要装的(***)

以下操作管理节点需要两个都安装，在3台数据库节点只要安装MHA的node节点：

1 # 如果安装下面包，报依赖关系错，请先安装mysql-share-compat包

2 # 先安装下面的 perl-dbd-mysql包

3 # 在下面执行perl时，如果出现报错，需要安装如下这几个perl包： perl-devel perl-CPAN

tar -zxf mha4mysql-node-0.53.tar.gz

cd mha4mysql-node-0.53

perl Makefile.PL

make && make install

管理节点还需要安装manger

tar -zxf  mha4mysql-manager-0.53.tar.gz

cd mha4mysql-manager-0.53

perl Makefile.PL

make && make install

修改MHA的配置文件

mkdir /etc/masterha

mkdir -p /master/app1

mkdir -p /scripts

cp samples/conf/* /etc/masterha/

cp samples/scripts/*  /scripts

cp samples/conf/* /etc/masterha/

vi /etc/masterha/app1.cnf

[server default]

manager_workdir=/var/log/masterha/app1

manager_log=/var/log/masterha/app1/manager.log

[server default]

manager_workdir=/masterha/app1

manager_log=/masterha/app1/manager.log

user=root

#mha管理用的账号（及时换行，不要有空格，否则会抱ssh的错误）

password=123456

ssh_user=root

#ssh的账号

repl_user=repl

#主从同步复制的账号

repl_password=repl

ping_interval=1

shutdown_script=""

master_ip_online_change_script=""

report_script=""

[server1]

hostname=192.168.78.128

master_binlog_dir=/usr/local/mysql/data

candidate_master=1

[server2]

hostname=192.168.78.129

master_binlog_dir=/usr/local/mysql/data

#candidate_master=1

[server3]

hostname=192.168.78.130

master_binlog_dir=/usr/local/mysql/data

no_master=1

masterha_default.cnf 文件置空

echo > masterha_default.cnf

四：测试配置

测试SSH可以无密码登录

~

[root@M128 masterha]# masterha_check_ssh --global_conf=/etc/masterha/masterha_default.cnf  --conf=/etc/masterha/app1.cnf

Tue Oct 27 20:47:50 2015 - [info] Reading default configuratoins from /etc/masterha/masterha_default.cnf..

Tue Oct 27 20:47:50 2015 - [info] Reading application default configurations from /etc/masterha/app1.cnf..

Tue Oct 27 20:47:50 2015 - [info] Reading server configurations from /etc/masterha/app1.cnf..

Tue Oct 27 20:47:50 2015 - [info] Starting SSH connection tests..

Tue Oct 27 20:47:50 2015 - [debug]

Tue Oct 27 20:47:50 2015 - [debug]  Connecting via SSH from root@192.168.78.128(192.168.78.128:22) to root@192.168.78.129(192.168.78.129:22)..

Tue Oct 27 20:47:50 2015 - [debug]   ok.

Tue Oct 27 20:47:50 2015 - [debug]  Connecting via SSH from root@192.168.78.128(192.168.78.128:22) to root@192.168.78.130(192.168.78.130:22)..

Tue Oct 27 20:47:50 2015 - [debug]   ok.

Tue Oct 27 20:47:51 2015 - [debug]

Tue Oct 27 20:47:50 2015 - [debug]  Connecting via SSH from root@192.168.78.129(192.168.78.129:22) to root@192.168.78.128(192.168.78.128:22)..

Tue Oct 27 20:47:50 2015 - [debug]   ok.

Tue Oct 27 20:47:50 2015 - [debug]  Connecting via SSH from root@192.168.78.129(192.168.78.129:22) to root@192.168.78.130(192.168.78.130:22)..

Tue Oct 27 20:47:51 2015 - [debug]   ok.

Tue Oct 27 20:47:51 2015 - [debug]

Tue Oct 27 20:47:51 2015 - [debug]  Connecting via SSH from root@192.168.78.130(192.168.78.130:22) to root@192.168.78.128(192.168.78.128:22)..

Tue Oct 27 20:47:51 2015 - [debug]   ok.

Tue Oct 27 20:47:51 2015 - [debug]  Connecting via SSH from root@192.168.78.130(192.168.78.130:22) to root@192.168.78.129(192.168.78.129:22)..

Tue Oct 27 20:47:51 2015 - [debug]   ok.

Tue Oct 27 20:47:51 2015 - [info] All SSH connection tests passed successfully.

如果报错，清空 ~/.ssh内的文件，重新配置无密码登录

测试MHA

[root@M128 masterha]# masterha_check_repl   --conf=/etc/masterha/app1.cnf

Tue Oct 27 20:50:24 2015 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.

Tue Oct 27 20:50:24 2015 - [info] Reading application default configurations from /etc/masterha/app1.cnf..

Tue Oct 27 20:50:24 2015 - [info] Reading server configurations from /etc/masterha/app1.cnf..

Tue Oct 27 20:50:24 2015 - [info] MHA::MasterMonitor version 0.53.

Tue Oct 27 20:50:25 2015 - [info] Multi-master configuration is detected. Current primary(writable) master is 192.168.78.128(192.168.78.128:3306)

Tue Oct 27 20:50:25 2015 - [info] Master configurations are as below:

Master 192.168.78.128(192.168.78.128:3306), replicating from 192.168.78.129(192.168.78.129:3306)

Master 192.168.78.129(192.168.78.129:3306), replicating from 192.168.78.128(192.168.78.128:3306), read-only

Tue Oct 27 20:50:25 2015 - [info] Dead Servers:

Tue Oct 27 20:50:25 2015 - [info] Alive Servers:

Tue Oct 27 20:50:25 2015 - [info]   192.168.78.128(192.168.78.128:3306)

Tue Oct 27 20:50:25 2015 - [info]   192.168.78.129(192.168.78.129:3306)

Tue Oct 27 20:50:25 2015 - [info]   192.168.78.130(192.168.78.130:3306)

Tue Oct 27 20:50:25 2015 - [info] Alive Slaves:

Tue Oct 27 20:50:25 2015 - [info]   192.168.78.129(192.168.78.129:3306)  Version=5.6.25-log (oldest major version between slaves) log-bin:enabled

Tue Oct 27 20:50:25 2015 - [info]     Replicating from 192.168.78.128(192.168.78.128:3306)

Tue Oct 27 20:50:25 2015 - [info]   192.168.78.130(192.168.78.130:3306)  Version=5.6.25-log (oldest major version between slaves) log-bin:enabled

Tue Oct 27 20:50:25 2015 - [info]     Replicating from 192.168.78.128(192.168.78.128:3306)

Tue Oct 27 20:50:25 2015 - [info]     Not candidate for the new Master (no_master is set)

Tue Oct 27 20:50:25 2015 - [info] Current Alive Master: 192.168.78.128(192.168.78.128:3306)

Tue Oct 27 20:50:25 2015 - [info] Checking slave configurations..

Tue Oct 27 20:50:25 2015 - [info]  read_only=1 is not set on slave 192.168.78.130(192.168.78.130:3306).

Tue Oct 27 20:50:25 2015 - [info] Checking replication filtering settings..

Tue Oct 27 20:50:25 2015 - [info]  binlog_do_db= , binlog_ignore_db=

Tue Oct 27 20:50:25 2015 - [info]  Replication filtering check ok.

Tue Oct 27 20:50:25 2015 - [info] Starting SSH connection tests..

Tue Oct 27 20:50:26 2015 - [info] All SSH connection tests passed successfully.

Tue Oct 27 20:50:26 2015 - [info] Checking MHA Node version..

Tue Oct 27 20:50:26 2015 - [info]  Version check ok.

Tue Oct 27 20:50:26 2015 - [info] Checking SSH publickey authentication settings on the current master..

Tue Oct 27 20:50:27 2015 - [info] HealthCheck: SSH to 192.168.78.128 is reachable.

Tue Oct 27 20:50:27 2015 - [info] Master MHA Node version is 0.53.

Tue Oct 27 20:50:27 2015 - [info] Checking recovery script configurations on the current master..

Tue Oct 27 20:50:27 2015 - [info]   Executing command: save_binary_logs --command=test --start_pos=4 --binlog_dir=/usr/local/mysql/data --output_file=/var/tmp/save_binary_logs_test --manager_version=0.53 --start_file=mysql-bin.000008

Tue Oct 27 20:50:27 2015 - [info]   Connecting to root@192.168.78.128(192.168.78.128)..

Creating /var/tmp if not exists..    ok.

Checking output directory is accessible or not..

ok.

Binlog found at /usr/local/mysql/data, up to mysql-bin.000008

Tue Oct 27 20:50:27 2015 - [info] Master setting check done.

Tue Oct 27 20:50:27 2015 - [info] Checking SSH publickey authentication and checking recovery script configurations on all alive slave servers..

Tue Oct 27 20:50:27 2015 - [info]   Executing command : apply_diff_relay_logs --command=test --slave_user=root --slave_host=192.168.78.129 --slave_ip=192.168.78.129 --slave_port=3306 --workdir=/var/tmp --target_version=5.6.25-log --manager_version=0.53 --relay_log_info=/usr/local/mysql/data/relay-log.info  --relay_dir=/usr/local/mysql/data/  --slave_pass=xxx

Tue Oct 27 20:50:27 2015 - [info]   Connecting to root@192.168.78.129(192.168.78.129:22)..

Checking slave recovery environment settings..

Opening /usr/local/mysql/data/relay-log.info ... ok.

Relay log found at /usr/local/mysql/data, up to M129-relay-bin.000002

Temporary relay log file is /usr/local/mysql/data/M129-relay-bin.000002

Testing mysql connection and privileges..Warning: Using a password on the command line interface can be insecure.

done.

Testing mysqlbinlog output.. done.

Cleaning up test file(s).. done.

Tue Oct 27 20:50:27 2015 - [info]   Executing command : apply_diff_relay_logs --command=test --slave_user=root --slave_host=192.168.78.130 --slave_ip=192.168.78.130 --slave_port=3306 --workdir=/var/tmp --target_version=5.6.25-log --manager_version=0.53 --relay_log_info=/usr/local/mysql/data/relay-log.info  --relay_dir=/usr/local/mysql/data/  --slave_pass=xxx

Tue Oct 27 20:50:27 2015 - [info]   Connecting to root@192.168.78.130(192.168.78.130:22)..

Checking slave recovery environment settings..

Opening /usr/local/mysql/data/relay-log.info ... ok.

Relay log found at /usr/local/mysql/data, up to M130-relay-bin.000003

Temporary relay log file is /usr/local/mysql/data/M130-relay-bin.000003

Testing mysql connection and privileges..Warning: Using a password on the command line interface can be insecure.

done.

Testing mysqlbinlog output.. done.

Cleaning up test file(s).. done.

Tue Oct 27 20:50:28 2015 - [info] Slaves settings check done.

Tue Oct 27 20:50:28 2015 - [info]

192.168.78.128 (current master)

+--192.168.78.129

+--192.168.78.130

Tue Oct 27 20:50:28 2015 - [info] Checking replication health on 192.168.78.129..

Tue Oct 27 20:50:28 2015 - [info]  ok.

Tue Oct 27 20:50:28 2015 - [info] Checking replication health on 192.168.78.130..

Tue Oct 27 20:50:28 2015 - [info]  ok.

Tue Oct 27 20:50:28 2015 - [warning] master_ip_failover_script is not defined.

Tue Oct 27 20:50:28 2015 - [warning] shutdown_script is not defined.

Tue Oct 27 20:50:28 2015 - [info] Got exit code 0 (Not master dead).

MySQL Replication Health is OK.

如果报错，按照报错信息修改用户权限，主从同步等。

至此说明你的MHA 已经配置好了

四：启动MHA