MHA由MHA節(jié)點(可以理解為子節(jié)點)及MHA管理節(jié)點2部分組成。因此對于MHA的安裝，相應的也分為2個部分，即安裝MHA節(jié)點，安裝MHA管理節(jié)點。本文基于CentOS 5.9 64bit簡要描述了MHA的安裝，同時也描述了在配置MHA時需要完成的等效性配置。供大家參考。

　　1、MHA的組成

　　MHA consists of MHA Manager and MHA Node packages. MHA Manager runs on a manager server, and MHA Node runs on each MySQL server. MHA Node programs do not run always, but are invoked from MHA manager programs when needed (at configuration check, failover, etc). Both MHA Manager and MHA Node are written in Perl.

　　2、安裝MHA Node

　　MHA Node has scripts and dependent perl modules that do the following.

　　save_binary_logs: Saving and copying dead master's binary logs

　　apply_diff_relay_logs: Identifying differential relay log events and applying all necessary log events

　　purge_relay_logs: Purging relay log files

　　You need to install MHA Node to all MySQL servers (both master and slave). You also need to install MHA Node on a management server because MHA Manager modules internally depend on MHA Node modules. MHA Manager internally connects to managed MySQL servers via SSH and executes MHA Node scripts. MHA Node does not depend on any external Perl modules except DBD::mysql so you should be able to install easily.

　　###本次安裝環(huán)境

　　# cat /etc/issue

　　CentOS release 5.9 (Final)

　　Kernel \r on an \m

　　###本次的演示環(huán)境

　　# more /etc/hosts

　　192.168.1.6 dbsrv1 #DB master

　　192.168.1.7 dbsrv2 #DB slave1

　　192.168.1.8 dbsrv3 #DB slave2

　　192.168.1.82 mysql-manager #DB manager node

　　###以下安裝包，建議node和manger都安裝

　　# yum install perl-DBD-MySQL

　　# yum install perl-Config-Tiny

　　# yum install perl-Log-Dispatch

　　# yum install perl-Parallel-ForkManager

　　###如果yum時相關相關包時，無法獲取到，建議配置epel后再安裝，需要注意對應的相關版本號。

　　# wget https://mirrors.ustc.edu.cn/fedora/epel/5/x86_64/epel-release-5-4.noarch.rpm

　　# rpm -Uvh epel-release-5-4.noarch.rpm

　　###以下安裝包從網(wǎng)絡上搜集整理，大家可根據(jù)情形自行決定是否安裝

　　# yum -y install perl-Config-IniFiles ncftp perl-Params-Validate perl-CPAN perl-Test-Mock-LWP.noarch \

　　> perl-LWP-Authen-Negotiate.noarch perl-devel perl-ExtUtils-CBuilder perl-ExtUtils-MakeMaker

　　# ls -hltr

　　total 172K

　　-rw-r--r-- 1 root root 112K Dec 5 15:46 mha4mysql-manager-0.56.tar.gz

　　-rw-r--r-- 1 root root 49K Dec 5 15:46 mha4mysql-node-0.56.tar.gz

　　# tar -xvf mha4mysql-node-0.56.tar.gz

　　# cd mha4mysql-node-0.56

　　# perl Makefile.PL

　　# make && make install

　　###驗證安裝后的幾個文件

　　[root@dbsrv1 bin]# ls apply_diff_relay_logs save_binary_logs filter_mysqlbinlog purge_relay_logs

　　apply_diff_relay_logs filter_mysqlbinlog purge_relay_logs save_binary_logs

　　3、安裝MHA Manager

　　MHA Manager has administrative command line programs such as masterha_manager, masterha_master_switch, etc, and dependent Perl modules. MHA Manager depends on the following Perl modules. You need to install them before installing MHA Manager. Do not forget to install MHA Node.

　　MHA Node package

　　DBD::mysql

　　Config::Tiny

　　Log::Dispatch

　　Parallel::ForkManager

　　Time::HiRes (included from Perl v5.7.3)

　　###以下部分為管理節(jié)點上的安裝，注，管理節(jié)點也要安裝MHA Node，此處省略

　　# tar -xvf mha4mysql-manager-0.56.tar.gz

　　# perl Makefile.PL

　　# make && make install

　　# ls /usr/bin/mast*

　　/usr/bin/masterha_check_repl /usr/bin/masterha_conf_host /usr/bin/masterha_master_switch

　　/usr/bin/masterha_check_ssh /usr/bin/masterha_manager /usr/bin/masterha_secondary_check

　　/usr/bin/masterha_check_status /usr/bin/masterha_master_monitor /usr/bin/masterha_stop

　　4、配置等效性

　　###為各節(jié)點配置hosts文件

　　# for i in 6 7 8;do scp /etc/hosts 192.168.1.$i:/etc/;done

　　[root@mysql-manager #]$ whoami

　　root

　　###配置等效性

　　[root@mysql-manager ~]# ssh-keygen

　　[root@mysql-manager ~]# ls -a ./.ssh/

　　. .. id_rsa id_rsa.pub

　　[root@mysql-manager ~]# ssh-copy-id -i ~/.ssh/id_rsa.pub root@192.168.1.6

　　[root@mysql-manager ~]# ssh-copy-id -i ~/.ssh/id_rsa.pub root@192.168.1.7

　　[root@mysql-manager ~]# ssh-copy-id -i ~/.ssh/id_rsa.pub root@192.168.1.8

　　###使用上面的方法在其余的幾個節(jié)點如法炮制后驗證等效性

　　[root@dbsrv2 ~]# ssh dbsrv1 date;ssh dbsrv2 date;ssh dbsrv3 date; ssh mysql-manager date;

　　###在管理節(jié)點端使用MHA命令驗證等效性

　　[root@mysql-manager ~]# masterha_check_ssh --conf=/etc/app1.cnf

　　Mon Feb 16 15:12:43 2015 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.

　　Mon Feb 16 15:12:43 2015 - [info] Reading application default configuration from /etc/app1.cnf..

　　Mon Feb 16 15:12:43 2015 - [info] Reading server configuration from /etc/app1.cnf..

　　Mon Feb 16 15:12:43 2015 - [info] Starting SSH connection tests..

　　Mon Feb 16 15:12:45 2015 - [debug]

　　Mon Feb 16 15:12:43 2015 - [debug] Connecting via SSH from mysql@192.168.1.6(192.168.1.6:22) tomysql@192.168.1.7(192.168.1.7:22)..

　　Mon Feb 16 15:12:44 2015 - [debug] ok.

　　Mon Feb 16 15:12:44 2015 - [debug] Connecting via SSH from mysql@192.168.1.6(192.168.1.6:22) tomysql@192.168.1.8(192.168.1.8:22)..

　　Mon Feb 16 15:12:44 2015 - [debug] ok.

　　Mon Feb 16 15:12:45 2015 - [debug]

　　Mon Feb 16 15:12:44 2015 - [debug] Connecting via SSH from mysql@192.168.1.7(192.168.1.7:22) tomysql@192.168.1.6(192.168.1.6:22)..

　　Mon Feb 16 15:12:44 2015 - [debug] ok.

　　Mon Feb 16 15:12:44 2015 - [debug] Connecting via SSH from mysql@192.168.1.7(192.168.1.7:22) tomysql@192.168.1.8(192.168.1.8:22)..

　　Mon Feb 16 15:12:44 2015 - [debug] ok.

　　Mon Feb 16 15:12:45 2015 - [debug]

　　Mon Feb 16 15:12:44 2015 - [debug] Connecting via SSH from mysql@192.168.1.8(192.168.1.8:22) tomysql@192.168.1.6(192.168.1.6:22)..

　　Mon Feb 16 15:12:45 2015 - [debug] ok.

　　Mon Feb 16 15:12:45 2015 - [debug] Connecting via SSH from mysql@192.168.1.8(192.168.1.8:22) tomysql@192.168.1.7(192.168.1.7:22)..

　　Mon Feb 16 15:12:45 2015 - [debug] ok.

　　Mon Feb 16 15:12:45 2015 - [info] All SSH connection tests passed successfully.