MySQL双主复制，即互为Master-Slave(只有一个Master提供写操作)，可以实现数据库服务器的热备，但是一个Master宕机后不能实现动态切换。而Keepalived通过虚拟IP，实现了双主对外的统一接口以及自动检查、失败切换机制。联合使用，可以实现MySQL数据库的高可用方案。

实验环境：

OS：centos 6.x x86_64系统

MySQL版本: ：mysql 5.6.22   64 位

A: master ：192.168.79.3 3306

B: slave ：192.168.79.4 3306

操作系统时间一致更改：

# date -s "20150319 15:51:42"

# hwclock --systohc

AB数据库安装及主从配置

新建mysql用户，用户组，创建 datadir

# groupadd mysql

# useradd mysql -g mysql -s /sbin/nologin -d /opt/mysql

解压mysql二进制安装包，对解压后的mysql目录加一个符号连接

# cd /opt/mysql

# tar -xvzf mysql-5.6.22-linux-glibc2.5-x86_64.tar.gz

# cd /usr/local/

# ln -s /opt/mysql/mysql-5.6.22-linux-glibc2.5-x86_64 mysql

# ls

bin etc games include lib lib64 libexec mysql sbin share src

创建mysql的安装目录并修改权限

# mkdir -p /data/mysql/mysql_3306/{data,logs,tmp}

chown -R mysql:mysql /data/mysql/

chown -R mysql:mysql /usr/local/mysql/

加环境变量,解决找不到mysql命令的问题

echo 'export PATH=$PATH:/usr/local/mysql/bin' >> /etc/profile

source /etc/profile

创建修改mysql配置文件

修改my.cnf

server_id

log_slave_updates

gtid-mode= off

binlog-ignore-db=mysql

replicate-ignore-db=mysql

auto_increment_offset= 1;

auto_increment_increment= 2;

ps：主从库的server_id不要一样。 如果从库是整个拷贝的uuid也不要一样，data下的auto.cnf.  从库：auto_increment_offset= 2;auto_increment_increment= 2;

初始化系统数据文件 ，在basedir下初始化

# ./scripts/mysql_install_db --user=mysql --defaults-file=/etc/my.cnf --datadir=/data/mysql/mysql_3306/data

安装mysql后的善后工作

cp /usr/local/mysql/support-files/mysql.server /etc/init.d/mysqld

/etc/init.d/mysql start

delete from mysql.user where user!='root' or host!='localhost';

truncate mysql.db;

drop database test;

grant all privileges on *.* to 'liyt'@'%' identified by 'liyt';

grant replication slave, replication client on *.* to 'repl'@'%' identified by 'replslave';

flush privileges;

reset master;

启动 slave mysql服务

A:

>show master status;

+-----------------+----------+--------------+------------------+-------------------+

| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |

+-----------------+----------+--------------+------------------+-------------------+

| mybinlog.000001 | 120 | | | |

+-----------------+----------+--------------+------------------+-------------------+

B:

change master to master_host='192.168.79.3', master_port=3306 ,master_user='repl', master_password='replslave', master_log_file='mybinlog.000001', master_log_pos=120;

B:

>show master status;

+-----------------+----------+--------------+------------------+-------------------+

| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |

+-----------------+----------+--------------+------------------+-------------------+

| mybinlog.000001 | 120 | | | |

+-----------------+----------+--------------+------------------+-------------------+

A:

change master to master_host='192.168.79.4', master_port=3306 ,master_user='repl', master_password='replslave', master_log_file='mybinlog.000001', master_log_pos=120;

测试双主同步：创建新的数据库和表看是否能同步

keepalived安装及配置

GRANT REPLICATION CLIENT ON *.* TO 'monitor'@'%' IDENTIFIED BY 'monitor';

#yum install keepalived

#yum install MySQL-python

配置A:

[root@taotao ~]# cat /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {

router_id MYSQL_3

}

vrrp_script chk_mysql {

script "/etc/keepalived/checkMySQL.py -h 192.168.79.3 -P 3306"

interval 60

}

vrrp_instance VI_MYSQL1 {

state BACKUP

nopreempt

interface eth0

virtual_router_id 82

priority 100

advert_int 5

authentication {

auth_type PASS

auth_pass 1111

}

track_script {

chk_mysql

}

virtual_ipaddress {

192.168.79.66

}

}

这里state不配置MASTER，是期望在MASTER宕机后再恢复时，不主动将MASTER状态抢过来，避免MySQL服务的波动。

由于不存在使用lvs进行负载均衡，不需要配置虚拟服务器virtual server，下同。

配置B:

[root@taotao ~]# cat /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {

router_id MYSQL_4

}

vrrp_script chk_mysql {

script "/etc/keepalived/checkMySQL.py -h 192.168.79.4 -P 3306"

interval 60

}

vrrp_instance VI_MYSQL1 {

state BACKUP

nopreempt

interface eth0

virtual_router_id 82

priority 90

advert_int 5

authentication {

auth_type PASS

auth_pass 1111

}

track_script {

chk_mysql

}

virtual_ipaddress {

192.168.79.66

}

}

checkMySQL.pyAB完全一样代码如下：

# cat /etc/keepalived/checkMySQL.py

#!/usr/bin/python

#coding: utf-8#

import sys

import os

importgetoptimport MySQLdb

import logging

dbhost='localhost'dbport=3306dbuser='monitor'dbpassword='monitor'def checkMySQL():

global dbhost

global dbport

global dbuser

global dbpassword

shortargs='h:P:'opts, args=getopt.getopt(sys.argv[1:],shortargs)for opt, value inopts:if opt=='-h':

dbhost=valueelif opt=='-P':

dbport=value

#print"host : %s, port: %d, user: %s, password: %s" % (dbhost, int(dbport), dbuser, dbpassword)

db=instanceMySQL(dbhost, dbport, dbuser, dbpassword)

st=db.ishaveMySQL()#if ( db.connect() != 0 ):# return1#db.disconnect()

return st

class instanceMySQL:

conn=None

def __init__(self, host=None,port=None, user=None, passwd=None):

self.dbhost=host

self.dbport= int(port)

self.dbuser=user

self.dbpassword= passwddef ishaveMySQL(self):

cmd="ps -ef | egrep -i \"mysqld\" | grep %s | egrep -iv \"mysqld_safe\" | grep -v grep | wc -l" %self.dbport

mysqldNum=os.popen(cmd).read()

cmd="netstat -tunlp | grep \":%s\" | wc -l" %self.dbport

mysqlPortNum=os.popen(cmd).read()

#print mysqldNum, mysqlPortNumif ( int(mysqldNum) <= 0):

print"error"return1

if ( int(mysqldNum) > 0 and mysqlPortNum <= 0):

return1return0def connect(self):

# print"in db conn"# print"host : %s, port: %d, user: %s, password: %s" %(self.dbhost, self.dbport, self.dbuser, self.dbpassword)

try:

self.conn=MySQLdb.connect(host="%s"%self.dbhost, port=self.dbport,user="%s"%dbuser, passwd="%s"%self.dbpassword)

except Exception, e:

# print"Error"print e

return1return0def disconnect(self):if(self.conn):

self.conn.close()

self.conn=Noneif __name__== "__main__":

st=checkMySQL()

sys.exit(st)

View Code

A B启用keepalived# /etc/init.d/keepalived startshell>chkconfig –level 2345 keepalived onps：先启动，你内心期望成为对外服务的机器，确认VIP绑定到那台机器上，然后在启动另外一台的keepalived

观察配置A的日志：

[root@taotao ~]# /etc/init.d/keepalived start

[root@taotao ~]# tail -f /var/log/messages

Mar 20 05:09:01 taotao Keepalived[56536]: Starting Keepalived v1.2.13 (10/15,2014)

Mar 20 05:09:01 taotao Keepalived[56538]:Starting Healthcheck child process, pid=56539

Mar 20 05:09:01 taotao Keepalived[56538]: Starting VRRP child process, pid=56540

Mar 20 05:09:01 taotao Keepalived_healthcheckers[56539]: Netlink reflector reports IP 192.168.79.3 added

Mar 20 05:09:01 taotao Keepalived_healthcheckers[56539]: Netlink reflector reports IP fe80::20c:29ff:fed8:3944 added

Mar 20 05:09:01 taotao Keepalived_healthcheckers[56539]: Registering Kernel netlink reflector

Mar 20 05:09:01 taotao Keepalived_healthcheckers[56539]: Registering Kernel netlink command channel

Mar 20 05:09:01 taotao Keepalived_vrrp[56540]: Netlink reflector reports IP 192.168.79.3 added

Mar 20 05:09:01 taotao Keepalived_vrrp[56540]: Netlink reflector reports IP fe80::20c:29ff:fed8:3944 added

Mar 20 05:09:01 taotao Keepalived_vrrp[56540]: Registering Kernel netlink reflector

Mar 20 05:09:01 taotao Keepalived_vrrp[56540]: Registering Kernel netlink command channel

Mar 20 05:09:01 taotao Keepalived_vrrp[56540]: Registering gratuitous ARP shared channel

Mar 20 05:09:01 taotao Keepalived_healthcheckers[56539]: Opening file '/etc/keepalived/keepalived.conf'.

Mar 20 05:09:01 taotao Keepalived_healthcheckers[56539]: Configuration is using : 6251 Bytes

Mar 20 05:09:01 taotao Keepalived_vrrp[56540]: Opening file '/etc/keepalived/keepalived.conf'.

Mar 20 05:09:01 taotao Keepalived_vrrp[56540]: Configuration is using : 63953 Bytes

Mar 20 05:09:01 taotao Keepalived_vrrp[56540]: Using LinkWatch kernel netlink reflector...

Mar 20 05:09:01 taotao Keepalived_healthcheckers[56539]: Using LinkWatch kernel netlink reflector...

Mar 20 05:09:01 taotao Keepalived_vrrp[56540]: VRRP_Instance(VI_MYSQL1)Entering BACKUP STATE

Mar 20 05:09:01 taotao Keepalived_vrrp[56540]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]

Mar 20 05:09:01 taotao Keepalived_vrrp[56540]: VRRP_Script(chk_mysql) succeeded

Mar 20 05:09:16 taotao Keepalived_vrrp[56540]: VRRP_Instance(VI_MYSQL1) Transition to MASTER STATE

Mar 20 05:09:21 taotao Keepalived_vrrp[56540]: VRRP_Instance(VI_MYSQL1) Entering MASTER STATE

Mar 20 05:09:21 taotao Keepalived_vrrp[56540]: VRRP_Instance(VI_MYSQL1) setting protocol VIPs.

Mar 20 05:09:21 taotao Keepalived_vrrp[56540]: VRRP_Instance(VI_MYSQL1) Sending gratuitous ARPs on eth0 for 192.168.79.66

Mar 20 05:09:21 taotao Keepalived_healthcheckers[56539]: Netlink reflector reports IP 192.168.79.66 added

Mar 20 05:09:26 taotao Keepalived_vrrp[56540]: VRRP_Instance(VI_MYSQL1) Sending gratuitous ARPs on eth0 for 192.168.79.66

ps：包含了三个进程： keepalived healthcheck vrrp协议 三个进程

测试：

1)关闭A服务的mysql服务观察A和B的日志

A：

[root@taotao ~]# /etc/init.d/mysqld stop

Shutting down MySQL....[ OK ]

[root@taotao ~]# tail -f /var/log/messages

Mar 20 05:36:04 taotao Keepalived_vrrp[56540]: VRRP_Script(chk_mysql) failed

Mar 20 05:36:07 taotao Keepalived_vrrp[56540]: VRRP_Instance(VI_MYSQL1) Entering FAULT STATE

Mar 20 05:36:07 taotao Keepalived_vrrp[56540]: VRRP_Instance(VI_MYSQL1) removing protocol VIPs.

Mar 20 05:36:07 taotao Keepalived_vrrp[56540]: VRRP_Instance(VI_MYSQL1) Now in FAULT state

Mar 20 05:36:07 taotao Keepalived_healthcheckers[56539]: Netlink reflector reports IP 192.168.79.66 removed

B：

[root@taotao ~]# tail -f /var/log/messages

Mar 20 05:36:03 slave1 Keepalived_vrrp[48658]: VRRP_Instance(VI_MYSQL1)Transition to MASTER STATE

Mar 20 05:36:08 slave1 Keepalived_vrrp[48658]: VRRP_Instance(VI_MYSQL1)Entering MASTER STATE

Mar 20 05:36:08 slave1 Keepalived_vrrp[48658]: VRRP_Instance(VI_MYSQL1) setting protocol VIPs.

Mar 20 05:36:08 slave1 Keepalived_vrrp[48658]: VRRP_Instance(VI_MYSQL1) Sending gratuitous ARPson eth0 for 192.168.79.66

Mar 20 05:36:08 slave1 Keepalived_healthcheckers[48657]: Netlink reflector reports IP192.168.79.66 added

Mar 20 05:36:13 slave1 Keepalived_vrrp[48658]: VRRP_Instance(VI_MYSQL1) Sending gratuitous ARPs on eth0 for 192.168.79.66

2)开启A服务的mysql服务观察A日志

A：

[root@taotao ~]# /etc/init.d/mysqld start

Starting MySQL...........................[ OK ]

[root@taotao ~]# tail -f /var/log/messages

Mar 20 05:42:01 taotao Keepalived_vrrp[56540]: VRRP_Script(chk_mysql) succeeded

Mar 20 05:42:03 taotao Keepalived_vrrp[56540]: VRRP_Instance(VI_MYSQL1)Entering BACKUP STATE

通过vip连接mysql

# mysql -h 192.168.79.66 -P 3306 -uliyt -p