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 import getopt import MySQLdb import logging dbhost='localhost' dbport=3306 dbuser='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 in opts: if opt=='-h': dbhost=value elif 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 ): # return 1 #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 = passwd def 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, mysqlPortNum if ( int(mysqldNum) <= 0): print "error" return 1 if ( int(mysqldNum) > 0 and mysqlPortNum <= 0): return 1 return 0 def 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 return 1 return 0 def disconnect(self): if (self.conn): self.conn.close() self.conn = None if __name__== "__main__": st=checkMySQL() sys.exit(st)