Mysql 如何做双机热备和负载均衡

http://lizhenliang.blog.51cto.com/7876557/1362313

http://blog.csdn.net/huaweitman/article/details/50853075

http://www.2cto.com/database/201608/543476.html

环境描述：

OS：CentOS6.5_X64

MASTER：192.168.0.202

BACKUP：192.168.0.203

VIP：192.168.0.204

1、配置两台Mysql主主同步

[root@master ~] # yum install mysql-server mysql -y
[root@master ~] # service mysqld start
[root@master ~] # mysqladmin -u root password 123.com
[root@master ~] # vi /etc/my.cnf  #开启二进制日志，设置id
[mysqld]
server- id  = 1                     #backup这台设置2
log-bin = mysql-bin
binlog-ignore-db = mysql,information_schema        #忽略写入binlog日志的库
auto-increment-increment = 2              #字段变化增量值
auto-increment-offset = 1               #初始字段ID为1
slave-skip-errors = all                        #忽略所有复制产生的错误
[root@master ~] # service mysqld restart

#先查看下log bin日志和pos值位置

master配置如下：

[root@ master ~] # mysql -u root -p123.com
mysql> GRANT  REPLICATION SLAVE ON *.* TO  'replication' @ '192.168.0.%'  IDENTIFIED  BY  'replication' ;
mysql> flush  privileges;
mysql> change  master to
    ->  master_host= '192.168.0.203' ,
    ->  master_user= 'replication' ,
    ->  master_password= 'replication' ,
    ->  master_log_file= 'mysql-bin.000002' ,
    ->  master_log_pos=106;   #对端状态显示的值
mysql> start  slave;          #启动同步

backup配置如下：

[root@backup ~] #  mysql -u root -p123.com
mysql> GRANT  REPLICATION SLAVE ON *.* TO  'replication' @ '192.168.0.%'  IDENTIFIED  BY  'replication' ;
mysql> flush  privileges;
mysql> change  master to
    ->  master_host= '192.168.0.202' ,
    ->  master_user= 'replication' ,
    ->  master_password= 'replication' ,
    ->  master_log_file= 'mysql-bin.000002' ,
    ->  master_log_pos=106;
mysql> start  slave;

#主主同步配置完毕，查看同步状态Slave_IO和Slave_SQL是YES说明主主同步成功。

在master插入数据测试下：

在backup查看是否同步成功：

可以看到已经成功同步过去，同样在backup插入到user表数据，一样同步过去，双主就做成功了。

2、配置keepalived实现热备

[root@backup ~]# yum install -y pcre-devel openssl-devel popt-devel #安装依赖包

[root@master ~] # wget http://www.keepalived.org/software/keepalived-1.2.7.tar.gz
[root@master ~] # tar zxvf keepalived-1.2.7.tar.gz
[root@master ~] # cd keepalived-1.2.7
[root@master ~] #./configure --prefix=/usr/local/keepalived
make  &&  make  install

#将keepalived配置成系统服务

[root@master ~] # cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
[root@master ~] # cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
[root@master ~] # mkdir /etc/keepalived/
[root@master ~] # cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
[root@master ~] # cp /usr/local/keepalived/sbin/keepalived /usr/sbin/

[root@master ~] # vi /etc/keepalived/keepalived.conf
! Configuration File forkeepalived
global_defs {
notification_email {
test @sina.com
 }
notification_email_from  admin@ test .com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id MYSQL_HA       #标识，双主相同
 }
vrrp_instance VI_1 {
 state BACKUP            #两台都设置BACKUP
 interface eth0
 virtual_router_id 51        #主备相同
 priority 100            #优先级，backup设置90
 advert_int 1
 nopreempt              #不主动抢占资源，只在master这台优先级高的设置，backup不设置
 authentication {
 auth_type PASS
 auth_pass 1111
 }
 virtual_ipaddress {
 192.168.0.204
 }
}
virtual_server 192.168.0.204 3306 {
 delay_loop 2
 #lb_algo rr              #LVS算法，用不到，我们就关闭了
 #lb_kind DR              #LVS模式，如果不关闭，备用服务器不能通过VIP连接主MySQL
 persistence_timeout 50   #同一IP的连接60秒内被分配到同一台真实服务器
 protocol TCP
 real_server 192.168.0.202 3306 {    #检测本地mysql，backup也要写检测本地mysql
 weight 3
 notify_down  /usr/local/keepalived/mysql .sh     #当mysq服down时，执行此脚本，杀死keepalived实现切换
 TCP_CHECK {
 connect_timeout 3     #连接超时
 nb_get_retry 3        #重试次数
 delay_before_retry 3  #重试间隔时间
  }
}

[root@master ~] # vi /usr/local/keepalived/mysql.sh
#!/bin/bash
pkill keepalived
[root@master ~] # chmod +x /usr/local/keepalived/mysql.sh
[root@master ~] # /etc/init.d/keepalived start

#backup服务器只修改priority为90、nopreempt不设置、real_server设置本地IP。

#授权两台Mysql服务器允许root远程登录，用于在其他服务器登陆测试！

mysql> grant all on *.* to'root'@'192.168.0.%' identified by '123.com';

mysql> flush privileges;

3、测试高可用性

1、通过Mysql客户端通过VIP连接，看是否连接成功。

2、停止master这台mysql服务，是否能正常切换过去，可通过ip addr命令来查看VIP在哪台服务器上。

3、可通过查看/var/log/messges日志，看出主备切换过程

4、master服务器故障恢复后，是否主动抢占资源，成为活动服务器。

本文出自 “李振良的技术博客” 博客，请务必保留此出处http://lizhenliang.blog.51cto.com/7876557/1362313