Linux下keepalived+Mysql主主同步实现数据库高可用实践

1）：编辑mysql配置文件/etc/my.cnf，选定主主同步的数据库

[mysqld]

datadir=/var/lib/mysql

socket=/var/lib/mysql/mysql.sock

user=mysql

symbolic-links=0

log-bin=binlog

binlog_format=mixed

server_id=1//主备两台mysql的server_id须不同

binlog-do-db=render

replicate-do-db=render

[mysqld_safe]

log-error=/var/log/mysqld.log

pid-file=/var/run/mysqld/mysqld.pid

2）：操作主数据库，" show master status "后记录下其 file 和p os ition

grant replication slave on *.* to 'slave'@'192.168.1.90' identified by '123456';

flush privileges;

show master status;

3）：操作从数据库，如果show slave status正常，则主从同步机制建立。同时也在从数据库上开启 master ，以便主数据库也能从从数据库同步数据

change master to master_host='192.168.1.33',master_user='slave',master_password='123456',master_port=3306,master_log_file='binlog.000001',master_log_pos=207017;

start slave;

show slave status;

grant replication slave on *.* to 'slave'@'192.168.1.33' identified by '123456';

flush privileges;

show master status;

4）：操作主数据库，如果show slave status正常，则主主同步机制建立完成。

master-mysql:

change master to master_host='192.168.1.90',master_user='slave',master_password='123456',master_port=3306,master_log_file='mysql-bin.000014',master_log_pos=2461;

start slave;

show slave status;

5）：数据库主主机制建立后，还需要在两台机器上都安装keepalived，以便向外提供一个VIP，当某台机器挂的时候，不影响数据库的使用。

a）需要安装ipvsadm和keepalived：yum install ipvsadm;yum install keepalived;

b）编辑/etc/keepalived/keepalived.conf。

global_defs {

   notification_email {

     [email protected]

     [email protected]

     [email protected]

   }

   notification_email_from [email protected]

   smtp_server 192.168.1.33

   smtp_connect_timeout 30

   router_id LVS_DEVEL

}

vrrp_script chk_mysqld{

   script "/etc/keepalived/mysql.sh"

   interval 3

   weight -20

}

vrrp_instance VI_1 {

    state MASTER//主备不同

    interface eth1

    virtual_router_id 51

    priority 100//主备不同，备的比主的要小

    advert_int 1

    authentication {

        auth_type PASS

        auth_pass 1111

    }

    virtual_ipaddress {

        192.168.1.13

    }

}

 

virtual_server 192.168.1.13 3306 {

    delay_loop 2

    lb_algo rr

    lb_kind DR

    persistence_timeout 60

    protocol TCP

    real_server 192.168.1.90 3306{//主备两台机器的实IP不同

        weight 3

        notify_down /etc/keepalived/mysql.sh

        TCP_CHECK{

            connect_timeout 3

            nb_get_retry 3

            connect_port 3306

        }

    }

}

c）编辑/etc/keepalived/mysql.sh。keepalived会定时启动 mysql.s h脚本检查数据库状态，当数据库异常时，杀死当前机器的keepalived，VIP将被另一台数据库机器绑定，从而实现数据库的高可用，平滑切换。

#!/bin/bash

MYSQL_OK=1

function check_mysql_helth (){

    mysql  -e "show status;" &>/dev/null

    if [ $? = 0 ] ;then

    MYSQL_OK=1         

    else       

    MYSQL_OK=0         

    fi                         

    return $MYSQL_OK           

}

while [ $CHECK_TIME -ne 0 ]

do

    let "CHECK_TIME -= 1"

    check_mysql_helth

if [ $MYSQL_OK = 1 ] ; then

    echo "mysql ok\n"

    CHECK_TIME=0

    exit 0

fi

if [ $MYSQL_OK -eq 0 ] &&  [ $CHECK_TIME -eq 0 ]

then

    pkill keepalived

    exit 1

fi

sleep 1

done

d）启动keepalived： /usr/sbin/keepalived -D 。使用VIP（这里是 192.168.1.13 ）连接数据库即可。