xkorey 2017-04-08
一、MMM简介:
MMM即Multi-Master Replication Manager for MySQL:mysql多主复制管理器,基于perl实现,关于mysql主主复制配置的监控、故障转移和管理的一套可伸缩的脚本套件(在任何时候只有一个节点可以被写入),MMM也能对从服务器进行读负载均衡,所以可以用它来在一组用于复制的服务器启动虚拟ip,除此之外,它还有实现数据备份、节点之间重新同步功能的脚本。MySQL本身没有提供replication failover的解决方案,通过MMM方案能实现服务器的故障转移,从而实现mysql的高可用。MMM不仅能提供浮动IP的功能,如果当前的主服务器挂掉后,会将你后端的从服务器自动转向新的主服务器进行同步复制,不用手工更改同步配置。这个方案是目前比较成熟的解决方案。详情请看官网:http://mysql-mmm.org
优点:高可用性,扩展性好,出现故障自动切换,对于主主同步,在同一时间只提供一台数据库写操作,保证的数据的一致性。当主服务器挂掉以后,另一个主立即接管,其他的从服务器能自动切换,不用人工干预。
缺点:monitor节点是单点,不过这个你也可以结合keepalived或者haertbeat做成高可用;至少三个节点,对主机的数量有要求,需要实现读写分离,还需要在前端编写读写分离程序。在读写非常繁忙的业务系统下表现不是很稳定,可能会出现复制延时、切换失效等问题。MMM方案并不太适应于对数据安全性要求很高,并且读、写繁忙的环境中。
适用场景:
MMM的适用场景为数据库访问量大,并且能实现读写分离的场景。
Mmm主要功能由下面三个脚本提供:
mmm_mond 负责所有的监控工作的监控守护进程,决定节点的移除(mmm_mond进程定时心跳检测,失败则将write ip浮动到另外一台master)等等
mmm_agentd 运行在mysql服务器上的代理守护进程,通过简单远程服务集提供给监控节点
mmm_control 通过命令行管理mmm_mond进程
在整个监管过程中,需要在mysql中添加相关授权用户,授权的用户包括一个mmm_monitor用户和一个mmm_agent用户,如果想使用mmm的备份工具则还要添加一个mmm_tools用户。
二、部署实施
1、环境介绍
OS:CentOS7.2(64位)数据库系统:mysql5.7.13
关闭selinux
配置ntp,同步时间
角色 | IP | hostname | Server-id | Write vip | Read vip |
Master1 | 192.168.31.83 | master1 | 1 | 192.168.31.2 | |
Master2(backup) | 192.168.31.141 | master2 | 2 | 192.168.31.3 | |
Slave1 | 192.168.31.250 | slave1 | 3 | 192.168.31.4 | |
Slave2 | 192.168.31.225 | slave2 | 4 | 192.168.31.5 | |
monitor | 192.168.31.106 | monitor1 | 无 |
2、在所有主机上配置/etc/hosts文件,添加如下内容:
192.168.31.83 master1
192.168.31.141 master2
192.168.31.250 slave1
192.168.31.225 slave2
192.168.31.106 monitor1
在所有主机上安装perl、perl-develperl-CPAN libart_lgpl.x86_64 rrdtool.x86_64 rrdtool-perl.x86_64包
#yum -y install perl-* libart_lgpl.x86_64 rrdtool.x86_64 rrdtool-perl.x86_64
注:使用centos7在线yum源安装
安装perl的相关库
#cpan -i Algorithm::Diff Class::Singleton DBI DBD::mysql Log::Dispatch Log::Log4perl Mail::Send Net::Ping Proc::Daemon Time::HiRes Params::Validate Net::ARP
3、在master1、master2、slave1、slave2主机上安装mysql5.7和配置复制
master1和master2互为主从,slave1、slave2为master1的从
在每个mysql的配置文件/etc/my.cnf中加入以下内容, 注意server_id不能重复。
master1主机:
log-bin = mysql-bin
binlog_format = mixed
server-id = 1
relay-log = relay-bin
relay-log-index = slave-relay-bin.index
log-slave-updates = 1
auto-increment-increment = 2
auto-increment-offset = 1
master2主机:
log-bin = mysql-bin
binlog_format = mixed
server-id = 2
relay-log = relay-bin
relay-log-index = slave-relay-bin.index
log-slave-updates = 1
auto-increment-increment = 2
auto-increment-offset = 2
slave1主机:
server-id = 3
relay-log = relay-bin
relay-log-index = slave-relay-bin.index
read_only = 1
slave2主机:
server-id = 4
relay-log = relay-bin
relay-log-index = slave-relay-bin.index
read_only = 1
在完成了对my.cnf的修改后,通过systemctl restart mysqld重新启动mysql服务
4台数据库主机若要开启防火墙,要么关闭防火墙或者创建访问规则:
firewall-cmd --permanent --add-port=3306/tcp
firewall-cmd --reload
主从配置(master1和master2配置成主主,slave1和slave2配置成master1的从):
在master1上授权:
mysql> grant replication slave on *.* to rep@'192.168.31.%' identified by '123456';
在master2上授权:
mysql> grant replication slave on *.* to rep@'192.168.31.%' identified by '123456';
把master2、slave1和slave2配置成master1的从库:
在master1上执行show master status; 获取binlog文件和Position点
mysql> show master status;
+------------------+----------+--------------+------------------+--------------------------------------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+---------------------------------------------------+
| mysql-bin.000001 | 452 | | | |
+------------------+----------+--------------+------------------+-----------------------------------------------------+
在master2、slave1和slave2执行
mysql> change master to master_host='192.168.31.83',master_port=3306,master_user='rep',master_password='123456',master_log_file='mysql-bin.000001',master_log_pos=452;
mysql>slave start;
验证主从复制:
master2主机:
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.31.83
Master_User: rep
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 452
Relay_Log_File: relay-bin.000002
Relay_Log_Pos: 320
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
slave1主机:
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.31.83
Master_User: rep
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 452
Relay_Log_File: relay-bin.000002
Relay_Log_Pos: 320
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
slave2主机:
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.31.83
Master_User: rep
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 452
Relay_Log_File: relay-bin.000002
Relay_Log_Pos: 320
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
如果Slave_IO_Running和Slave_SQL_Running都为yes,那么主从就已经配置OK了
把master1配置成master2的从库:
在master2上执行show master status ;获取binlog文件和Position点
mysql> show master status;
+------------------+----------+--------------+------------------+--------------------------------------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+---------------------------------------------------+
| mysql-bin.000001 | 452 | | | |
+------------------+----------+--------------+------------------+----------------------------------------------------+
在master1上执行:
mysql> change master to master_host='192.168.31.141',master_port=3306,master_user='rep',master_password='123456',master_log_file='mysql-bin.000001',master_log_pos=452;
mysql> start slave;
验证主从复制:
master1主机:
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.31.141
Master_User: rep
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 452
Relay_Log_File: relay-bin.000002
Relay_Log_Pos: 320
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
如果Slave_IO_Running和Slave_SQL_Running都为yes,那么主从就已经配置OK了