每台主机均需安装keepalived，mysql，安装过程这里不多介绍，不懂的可自行百度。
本次配置的环境为
DB1：192.168.31.190 DB2：192.168.31.184 MySQL VIP：192.168.31.189
1、修改MySQL配置文件
首先修改DB1的/etc/my.cnf配置文件，在"[mysqld]"段中添加一下内容：
server-id = 1 log-bin=mysql-bin relay-log = mysql-relay-bin replicate-wild-ignore-table=mysql.% replicate-wild-ignore-table=test.% replicate-wild-ignore-table=information_schema.%
然后修改DB2主机/etc/my.cnf配置文件,在"[mysqld]"段添加一下内容:
server-id = 2 log-bin=mysql-bin relay-log = mysql-relay-bin replicate-wild-ignore-table=mysql.% replicate-wild-ignore-table=test.% replicate-wild-ignore-table=information_schema.%
2、手动同步数据库
DB1和DB2数据需要保持同步，在DB1上执行操作
mysql> FLUSH TABLES WITH READ LOCK; Query OK,0 rows affected (0.00 sec) #然后不要退出终端，重开一个终端，执行一下命令 # cd /var/lib/ # tar zcvf mysql.tar.gz mysql # scp mysql.tar.gz DB2:/var/lib/
将数据传输到DB2后解压覆盖然后依次重启DB1和DB2上的MySQL
3、创建复制用户并授权
在DB1MySQL执行如下操作：
mysql> grant replication slave on *.* to ‘repl_user‘@‘192.168.31.184‘ identified by ‘repl_passwd‘; mysql> show master status;
然后在DB2的MySQL将DB1设为自己的主服务器，操作如下：
mysql> change master to -> master_host=‘192.168.31.190‘, -> master_user=‘repl_user‘, -> master_password=‘repl_passwd‘, -> master_log_file=‘mysql-bin.000001‘, -> master_log_pos=106; #接着启动slave服务 mysql> start slave；
#查看slave运行状态 mysql> show slave status\G;
到这里，从DB1到DB2的MySQL主从复制已经完成，接下来配置DB2到DB1的mysql主从复制，过程和上面完全一样，在DB2的MySQL创建复制用户：
mysql> grant replication slave on *.* to ‘repl_user‘@‘192.168.31.190‘ identified by ‘repl_passwd‘; mysql> show master status;
然后在DB1的MySQL将DB2设为自己的主服务器：
mysql> change master to -> master_host=‘192.168.31.184‘, -> master_user=‘repl_user‘, -> master_password=‘repl_passwd‘, -> master_log_file=‘mysql-bin.000001‘, -> master_log_pos=436; mysql> start slave； mysql> show slave status\G;
接着启动slave服务。至此，MySQL双主模式的主从复制配置完毕。
4、配置keepalived实现MySQL双主高可用
首先在DB1上配置/etc/keepalived/keepalived.conf，内容如下
global_defs { notification_email { acassen@firewall.loc failover@firewall.loc sysadmin@firewall.loc } notification_email_from Alexandre.Cassen@firewall.loc smtp_server 192.168.200.1 smtp_connect_timeout 30 router_id LVS_DEVEL } vrrp_script check_mysqld { script "/etc/keepalived/mysqlcheck/check_slave.pl 127.0.0.1"#检测mysql复制状态脚本 interval 2 weight 21 } vrrp_instance HA_1 { state BACKUP #在DB1和DB2均为BACKUP interface eth1 virtual_router_id 80 priority 100 advert_int 2 nopreempt #不抢占模式，只在优先级高的机器设置 authentication { auth_type PASS auth_pass qweasdzxc track_script { check_mysqld } virtual_ipaddress { 192.168.31.189/24 dev eth1 #mysql对外服务IP，即VIP } }
其中，/etc/keepalived/mysqlcheck/check_slave.pl文件的内容如下：
#!/usr/bin/perl -w use DBI; use DBD::mysql; #CONFIG VARIABLES $SBM = 120; $db = "ixdba"; $host = $ARGV[0]; $port = 3306; $user = "root"; $pw = "915389546"; #SQL query $query = "show slave status"; $dbh = DBI->connect("DBI:mysql:$db:$host:$port",$user,$pw,{ RaiseError => 0,PrintError => 0 }); if (!defined($dbh)) { exit 1; } $sqlQuery = $dbh->prepare($query); $sqlQuery->execute; $Slave_IO_Running = ""; $Slave_SQL_Running = ""; $Seconds_Behind_Master = ""; while (my $ref = $sqlQuery->fetchrow_hashref()) { $Slave_IO_Running = $ref->{‘Slave_IO_Running‘}; $Slave_SQL_Running = $ref->{‘Slave_SQL_Running‘}; $Seconds_Behind_Master = $ref->{‘Second_Behind_Master‘}; } $sqlQuery->finish; $dbh->disconnect(); if ( $Slave_IO_Running eq "NO" || $Slave_SQL_Running eq "NO" ) { exit 1; } else { if ( $Seconds_Behind__Master > $SBM) { exit 1; } else { exit 0; } }
接着将keepalived和check_slave.pl复制到DB2服务器上对应的位置，然后将keepalived文件中的priority值修改为90，还需去掉nopreempt选项，然后分别在DB1和DB2上启动keepalived服务。
5、测试主从同步功能
首先从第三台服务器远程登录VIP为“192.168.31.188“的数据库，操作过程如下：
[root@localhost~]#mysql -uroot -p -h 192.168.31.188
Enter password:
MySQL [(none)]> show variables like "%hostname%"; +---------------+----------------+ | Variable_name | Value | +---------------+----------------+ | hostname | DB1 | +---------------+----------------+ 1 row in set (0.01 sec) MySQL [(none)]> show variables like "%server_id%"; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | server_id | 1 | +---------------+-------+ 1 row in set (0.01 sec)
#可以看到成功通过VIP登录，并且登录了DB1服务器。
#接下来测试复制数据功能 MySQL [(none)]> create database repldb; Query OK, 1 row affected (0.12 sec) MySQL [(none)]> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | repldb | | test | +--------------------+ 5 rows in set (0.01 sec) MySQL [(none)]> use repldb; Database changed MySQL [repldb]> create table repl_table(id int,email varchar(80),password varchar(40) not null); Query OK, 0 rows affected (0.03 sec) MySQL [repldb]> show tables; +------------------+ | Tables_in_repldb | +------------------+ | repl_table | +------------------+ 1 row in set (0.00 sec) MySQL [repldb]> insert into repl_table (id,email,password) values(1,"xiaoming@qq.com","123456"); Query OK, 1 row affected (0.00 sec)
然后登录DB2主机的MySQL查看，可以发现数据实现了同步。
6、故障转移测试
首先远程通过VIP地址登录MySQL系统，不要退出这个连接，然后在DB1服务器的MySQL命令行执行如下操作：
mysql>slave stop;
然后回到远程连接的MySQL数据库执行如下操作：
MySQL [(none)]> show variables like "%hostname%"; +---------------+----------------+ | Variable_name | Value | +---------------+----------------+ | hostname | DB2 | +---------------+----------------+ 1 row in set (0.01 sec) MySQL [(none)]> show variables like "%server_id%"; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | server_id | 2 | +---------------+-------+ 1 row in set (0.01 sec)
可以发现在DB1发现故障之后MySQL服务从DB1切换到了DB2服务器，至此，所有配置完成。
