MMM配置官方文档: http://mysql-mmm.org/mmm2:guide
本文环境:
主库：CentOS6.7 x64 192.168.0.201 mysql-5.6.29
主库：CentOS6.7 x64 192.168.0.202 mysql-5.6.29
备库：CentOS6.7 x64 192.168.0.203 mysql-5.6.29
备库：CentOS6.7 x64 192.168.0.204 mysql-5.6.29
管理：CentOS6.7 x64 192.168.0.205
MMM服务器角色对应关系:
node1(主1) 192.168.0.201 db1 1
node2(主2) 192.168.0.202 db2 2
node3(从1) 192.168.0.203 db3 11
node4(从1) 192.168.0.204 db4 12
node5(监控) 192.168.0.205 mon -
配置完成后，使用下面的VIP访问MySQL Cluster。
192.168.0.211 writer
192.168.0.212 reader
192.168.0.213 reader
192.168.0.214 reader
192.168.0.215 reader
一、双主环境，以及从服务器环境准备
1，node1(主1) /etc/my.cnf
[mysqld]
server-id = 1
binlog-format = ROW
log-bin = master-bin
log-bin-index = master-bin.index
log-slave-updates = true
auto_increment_offset = 1
auto_increment_increment = 2
mysql> show master status;
+-------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+-------------------+----------+--------------+------------------+-------------------+
| master-bin.000001 | 120 | | | |
+-------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
mysql>
2. node1(主2) /etc/my.cnf
[mysqld]
server-id = 2
binlog-format = ROW
log-bin = master-bin
log-bin-index = master-bin.index
log-slave-updates = true
auto_increment_offset = 2
auto_increment_increment = 2
mysql> show master status;
+-------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+-------------------+----------+--------------+------------------+-------------------+
| master-bin.000001 | 120 | | | |
+-------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
mysql>
3. node1,node2 双主服务器配置同步复制帐号
grant replication slave on *.* to 'repl'@'%' identified by '123456';
flush privileges;
4, node3（从）/etc/my.cnf
[mysqld]
binlog-format = ROW
log-bin = mysql-bin
relay-log = slave-relay-bin
relay-log-index = slave-relay-bin.index
log-slave-updates = true
server-id = 11
skip-name-resolve
5， node4（从）/etc/my.cnf
[mysqld]
binlog-format = ROW
log-bin = mysql-bin
relay-log = slave-relay-bin
relay-log-index = slave-relay-bin.index
log-slave-updates = true
server-id = 12
skip-name-resolve
6. node1从库配置同步过程
(1) 配置同步，手动执行同步参数，该配置会写入master.info文件中。
mysql >
CHANGE MASTER TO
MASTER_HOST='192.168.0.202',
MASTER_PORT=3306,
MASTER_USER='repl',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='master-bin.000001',
MASTER_LOG_POS=120;
mysql> start slave;
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.0.202
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: master-bin.000001
Read_Master_Log_Pos: 407
Relay_Log_File: node1-relay-bin.000002
Relay_Log_Pos: 571
Relay_Master_Log_File: master-bin.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
7. node1从库配置同步过程
(1) 配置同步，手动执行同步参数，该配置会写入master.info文件中。
mysql >
CHANGE MASTER TO
MASTER_HOST='192.168.0.201',
MASTER_PORT=3306,
MASTER_USER='repl',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='master-bin.000001',
MASTER_LOG_POS=120;
mysql> start slave;
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.0.201
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: master-bin.000001
Read_Master_Log_Pos: 694
Relay_Log_File: node2-relay-bin.000002
Relay_Log_Pos: 571
Relay_Master_Log_File: master-bin.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
8. 测试双主相互复制
(1) node1上创建数据库
mysql> create database mydb;
Query OK, 1 row affected (0.00 sec)
mysql> use mydb;
Database changed
mysql> show tables;
+----------------+
| Tables_in_mydb |
+----------------+
| user |
+----------------+
1 row in set (0.01 sec)
mysql> select * from user;
+----+----------+----------+
| id | username | password |
+----+----------+----------+
| 1 | koumm | 123456 |
+----+----------+----------+
1 row in set (0.01 sec)
mysql>
(2) node2上的操作如下：
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mydb |
| mysql |
| performance_schema |
+--------------------+
4 rows in set (0.00 sec)
mysql> use mydb;
Database changed
mysql> CREATE TABLE `user` (
-> `id` varchar(20) NOT NULL,
-> `username` varchar(20) NOT NULL,
-> `password` char(32) NOT NULL,
-> PRIMARY KEY (`id`)
-> ) ;
Query OK, 0 rows affected (0.14 sec)
mysql> INSERT INTO user VALUES ('1', 'koumm', '123456');
Query OK, 1 row affected (0.00 sec)
mysql>
二、配置node3, node4同步node1(主)
1，node1主库锁表，导数据库
(1) 主库锁表
mysql> flush tables with read lock;
Query OK, 0 rows affected (0.00 sec)
mysql> show master status;
+-------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+-------------------+----------+--------------+------------------+-------------------+
| master-bin.000001 | 1226 | | | |
+-------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
(2) 主库备份
[root@master ~]# mysqldump -uroot -p -B mydb > mydb.sql
说明：-B参数有建库语句。
(3) 主库解开锁表功能
mysql> unlock tables;
Query OK, 0 rows affected (0.00 sec)
mysql>
2. node3,node4从库导入数据库
# mysql -uroot -padmin < mydb.sql
3. node3,node4 从库配置同步过程
(1) 配置同步，手动执行同步参数，该配置会写入master.info文件中。
mysql >
CHANGE MASTER TO
MASTER_HOST='192.168.0.201',
MASTER_PORT=3306,
MASTER_USER='repl',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='master-bin.000001',
MASTER_LOG_POS=1226;
mysql> start slave;
Query OK, 0 rows affected (0.04 sec)
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.1.121
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: master-bin.000005
Read_Master_Log_Pos: 730
Relay_Log_File: slave-relay-bin.000002
Relay_Log_Pos: 284
Relay_Master_Log_File: master-bin.000005
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
可以简单测试一下同步数据情况。
三、配置MMM过程
1, 安装mmm软件包
(1) node1,node2,node3,node4,node5节点
# wget http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
# rpm -ivh epel-release-6-8.noarch.rpm
(2) node5(监控节点)
# yum install mysql-mmm mysql-mmm-agent mysql-mmm-tools mysql-mmm-monitor
(3) node1,node2,node3,node4 (mysql节点)
# yum install mysql-mmm-agent
2，所有的MySQL节点添加以下两个用户，这里可以在主库做该操作，会自动同步到其它节点。
mysql> grant replication client on *.* to 'mmm_monitor'@'192.168.0.%' identified by '123456';
mysql> grant super, replication client, process on *.* to 'mmm_agent'@'192.168.0.%' identified by '123456';
mysql> flush privileges;
3，所有主机node1,node2,node3,node4,node5上创建如下文件
[root@node1 ~]# vi /etc/mysql-mmm/mmm_common.conf
active_master_role writer
<host default>
cluster_interface eth0
pid_path /var/run/mysql-mmm/mmm_agentd.pid
bin_path /usr/libexec/mysql-mmm/
replication_user repl
replication_password 123456
agent_user mmm_agent
agent_password 123456
</host>
<host db1>
ip 192.168.0.201
mode master
peer db2
</host>
<host db2>
ip 192.168.0.202
mode master
peer db1
</host>
<host db3>
ip 192.168.0.203
mode slave
</host>
<host db4>
ip 192.168.0.204
mode slave
</host>
<role writer>
hosts db1, db2
ips 192.168.0.211
mode exclusive
</role>
<role reader>
hosts db1, db2, db3, db4
ips 192.168.0.212,192.168.0.213,192.168.0.214,192.168.0.215
mode balanced
</role>
复制该配置文件到所有节点上:
[root@node1 ~]# scp /etc/mysql-mmm/mmm_common.conf node2:/etc/mysql-mmm/
[root@node1 ~]# scp /etc/mysql-mmm/mmm_common.conf node3:/etc/mysql-mmm/
[root@node1 ~]# scp /etc/mysql-mmm/mmm_common.conf node4:/etc/mysql-mmm/
[root@node1 ~]# scp /etc/mysql-mmm/mmm_common.conf node5:/etc/mysql-mmm/
4. 配置agent代理节点，所有mysql主从服务器均为代理节点
(1) node1,node2,node3,node4 的MySQL节点配置mmm_agent.conf
# vi /etc/mysql-mmm/mmm_agent.conf
include mmm_common.conf
this db1 #在四台mysql节点上设置对应的db，分别为db1、db2、db3、db4
(2) 默认为启用，可以不用修改
# cat /etc/default/mysql-mmm-agent
# mysql-mmm-agent defaults
ENABLED=1
(3) mysql节点启动服务
# chkconfig mysql-mmm-agent on
# /etc/init.d/mysql-mmm-agent start
5，配置MMM管理监控节点node5
(1) 配置监控
[root@node5 ~]# vi /etc/mysql-mmm/mmm_mon.conf
include mmm_common.conf
<monitor>
ip 127.0.0.1
pid_path /var/run/mysql-mmm/mmm_mond.pid
bin_path /usr/libexec/mysql-mmm
status_path /var/lib/mysql-mmm/mmm_mond.status
ping_ips 192.168.0.201,192.168.0.202,192.168.0.203,192.168.0.204
auto_set_online 30
# The kill_host_bin does not exist by default, though the monitor will
# throw a warning about it missing. See the section 5.10 "Kill Host
# Functionality" in the PDF documentation.
#
# kill_host_bin /usr/libexec/mysql-mmm/monitor/kill_host
#
</monitor>
<host default>
monitor_user mmm_monitor
monitor_password 123456
</host>
debug 0
(2) mysql节点启动服务
# chkconfig mysql-mmm-monitor on
# /etc/init.d/mysql-mmm-monitor start
6， 查看状态
(1) 管理服务器上查看状态
[root@node1 ~]# mmm_control show
db1(192.168.0.201) master/ONLINE. Roles: reader(192.168.0.215), writer(192.168.0.211)
db2(192.168.0.202) master/ONLINE. Roles: reader(192.168.0.213)
db3(192.168.0.203) slave/ONLINE. Roles: reader(192.168.0.212)
db4(192.168.0.204) slave/ONLINE. Roles: reader(192.168.0.214)
[root@node1 ~]# mmm_control checks all
db4 ping [last change: 2016/04/27 16:45:49] OK
db4 mysql [last change: 2016/04/27 16:45:49] OK
db4 rep_threads [last change: 2016/04/27 16:45:49] OK
db4 rep_backlog [last change: 2016/04/27 16:45:49] OK: Backlog is null
db2 ping [last change: 2016/04/27 16:45:49] OK
db2 mysql [last change: 2016/04/27 16:45:49] OK
db2 rep_threads [last change: 2016/04/27 16:45:49] OK
db2 rep_backlog [last change: 2016/04/27 16:45:49] OK: Backlog is null
db3 ping [last change: 2016/04/27 16:45:49] OK
db3 mysql [last change: 2016/04/27 16:45:49] OK
db3 rep_threads [last change: 2016/04/27 16:45:49] OK
db3 rep_backlog [last change: 2016/04/27 16:45:49] OK: Backlog is null
db1 ping [last change: 2016/04/27 16:45:49] OK
db1 mysql [last change: 2016/04/27 16:45:49] OK
db1 rep_threads [last change: 2016/04/27 16:45:49] OK
db1 rep_backlog [last change: 2016/04/27 16:45:49] OK: Backlog is null
[root@node1 ~]#
(2) 服务器的启动VIP地址
[root@node1 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:ff:33:6a brd ff:ff:ff:ff:ff:ff
inet 192.168.0.201/24 brd 192.168.0.255 scope global eth0
inet 192.168.0.215/32 scope global eth0
inet 192.168.0.211/32 scope global eth0
inet6 fe80::20c:29ff:feff:336a/64 scope link
valid_lft forever preferred_lft forever
[root@node1 ~]#
[root@node2 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:8c:60:58 brd ff:ff:ff:ff:ff:ff
inet 192.168.0.202/24 brd 192.168.0.255 scope global eth0
inet 192.168.0.213/32 scope global eth0
inet6 fe80::20c:29ff:fe8c:6058/64 scope link
valid_lft forever preferred_lft forever
[root@node2 ~]#
服务器读写采有VIP地址进行读写，出现故障时VIP会漂移到其它节点，由其它节点提供服务。
四、MMM高可用测试
首先查看整个集群的状态，可以看到整个集群状态正常。
[root@node5 ~]# mmm_control show
db1(192.168.0.201) master/ONLINE. Roles: reader(192.168.0.212), writer(192.168.0.211)
db2(192.168.0.202) master/ONLINE. Roles: reader(192.168.0.213)
db3(192.168.0.203) slave/ONLINE. Roles: reader(192.168.0.215)
db4(192.168.0.204) slave/ONLINE. Roles: reader(192.168.0.214)
[root@192.168.0.30 ~]#
1. 模拟node2宕机，手动停止mysql服务，观察monitor日志node2由关闭到启动的日志如下：
[root@192.168.0.30 ~]# tail -f /var/log/mysql-mmm/mmm_mond.log
2016/04/29 09:58:33 FATAL State of host 'db2' changed from ONLINE to HARD_OFFLINE (ping: OK, mysql: not OK)
2016/04/29 10:00:54 FATAL State of host 'db2' changed from HARD_OFFLINE to AWAITING_RECOVERY
2016/04/29 10:01:24 FATAL State of host 'db2' changed from AWAITING_RECOVERY to ONLINE because of auto_set_online(30 seconds). It was in state AWAITING_RECOVERY for 30
seconds
重新查看集群的最新状态：
[root@node5 ~]# mmm_control show
db1(192.168.0.201) master/ONLINE. Roles: reader(192.168.0.212), writer(192.168.0.211)
db2(192.168.0.202) master/HARD_OFFLINE. Roles: #从日志发现db2的状态有ONLINE转换为HARD_OFFLINE
db3(192.168.0.203) slave/ONLINE. Roles: reader(192.168.0.213), reader(192.168.0.215)
db4(192.168.0.204) slave/ONLINE. Roles: reader(192.168.0.214)
[root@node5 ~]# mmm_control checks all
db4 ping [last change: 2016/04/29 09:01:08] OK
db4 mysql [last change: 2016/04/29 09:01:08] OK
db4 rep_threads [last change: 2016/04/29 09:01:08] OK
db4 rep_backlog [last change: 2016/04/29 09:01:08] OK: Backlog is null
db2 ping [last change: 2016/04/29 09:01:08] OK
db2 mysql [last change: 2016/04/29 09:58:33] ERROR: Connect error (host = 192.168.0.202:3306, user = mmm_monitor)! Lost connection to MySQL server at 'reading
initial communication packet', system error: 111 能ping通，说明只是服务死掉了。
db2 rep_threads [last change: 2016/04/29 09:01:08] OK
db2 rep_backlog [last change: 2016/04/29 09:01:08] OK: Backlog is null
db3 ping [last change: 2016/04/29 09:01:08] OK
db3 mysql [last change: 2016/04/29 09:01:08] OK
db3 rep_threads [last change: 2016/04/29 09:01:08] OK
db3 rep_backlog [last change: 2016/04/29 09:01:08] OK: Backlog is null
db1 ping [last change: 2016/04/29 09:01:08] OK
db1 mysql [last change: 2016/04/29 09:56:33] OK
db1 rep_threads [last change: 2016/04/29 09:01:08] OK
db1 rep_backlog [last change: 2016/04/29 09:01:08] OK: Backlog is null
[root@node5 ~]#
启动node2，node2由HARD_OFFLINE转到AWAITING_RECOVERY状态。这里db2再次接管读请求。
[root@node5 ~]# mmm_control show
db1(192.168.0.201) master/ONLINE. Roles: reader(192.168.0.212), writer(192.168.0.211)
db2(192.168.0.202) master/ONLINE. Roles: reader(192.168.0.213)
db3(192.168.0.203) slave/ONLINE. Roles: reader(192.168.0.215)
db4(192.168.0.204) slave/ONLINE. Roles: reader(192.168.0.214)
[root@node5 ~]#
2. 模拟node1主库宕机，查看集群状态。
[root@node5 ~]# mmm_control show
db1(192.168.0.201) master/HARD_OFFLINE. Roles:
db2(192.168.0.202) master/ONLINE. Roles: reader(192.168.0.213), writer(192.168.0.211)
db3(192.168.0.203) slave/ONLINE. Roles: reader(192.168.0.212), reader(192.168.0.215)
db4(192.168.0.204) slave/ONLINE. Roles: reader(192.168.0.214)
node1主库再启动：
[root@node5 ~]# mmm_control show
db1(192.168.0.201) master/ONLINE. Roles: reader(192.168.0.212)
db2(192.168.0.202) master/ONLINE. Roles: reader(192.168.0.213), writer(192.168.0.211)
db3(192.168.0.203) slave/ONLINE. Roles: reader(192.168.0.215)
db4(192.168.0.204) slave/ONLINE. Roles: reader(192.168.0.214)
可以看到主库启动用会自动转到读的角色，不会接管主，只到现有的主再次宕机。
[root@192.168.0.30 ~]# tail -f /var/log/mysql-mmm/mmm_mond.log
2016/04/29 10:03:25 FATAL State of host 'db1' changed from ONLINE to HARD_OFFLINE (ping: OK, mysql: not OK)
2016/04/29 10:06:20 FATAL State of host 'db1' changed from HARD_OFFLINE to AWAITING_RECOVERY
2016/04/29 10:06:51 FATAL State of host 'db1' changed from AWAITING_RECOVERY to ONLINE because of auto_set_online(30 seconds). It was in state AWAITING_RECOVERY for 31
seconds
3. 测试小结：
(1)node2备选主节点宕机不影响集群的状态，就是移除了node2备选节点的读状态。
(2)node1主节点宕机，由node2备选主节点接管写角色，node3,node4指向新node2主库进行复制，node3,node4会自动change master到node2.
(3)问题来了：
如果node1主库宕机，node2复制应用又落后于node1时就变成了主可写状态，这进的数据主无法保证一致性。
如果node2,node3,node4延迟于node1主，这个时node1宕机，node3,node4将会等待数据追上db1后，再重新指向新的主node2进行复制操作，这时的数据也无法保证同步的一致性。
(4)如查采用MMM高可用架构，主，主备选节点机器配置一样，而且开启半同步进一步提高安全性或采用MariaDB进行多线程从复制，提高复制的性能。
说明：MMM（Master-Master Replication Manager for MySQL）主主复制管理器, MMM集群套件具有良好的稳定性、高可用性和可扩展性。当活动的Master节点出现故障时，备用Master节点可以立即接管，而其他的Slave节点也能自动切换到备用Master节点继续进行同步复制，而无需人为干涉；MMM架构需要多个节点、多个IP，对服务器数量有要求，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。
本文转自 koumm 51CTO博客，原文链接：http://blog.51cto.com/koumm/1768381，如需转载请自行联系原作者
