基于Multi Master MySQL(MMM)实现Mariadb10读写分离
----本文大纲
简介
资源配置
拓扑图
实现过程
一、简介
MMM即Master-Master Replication Manager for MySQL（mysql主主复制管理器）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），这个套件也能对居于标准的主从配置的任意数量的从服务器进行读负载均衡，所以你可以用它来在一组居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，更可贵的是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。
方案优缺点
优点：安全性、稳定性高，可扩展性好，高可用，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：至少三个节点，对主机的数量有要求，需要实现读写分离，对程序来说是个挑战。
二、资源配置
主机属性
| 系统 | 名字 | 角色 | 主机名 | ip地址 | 关系 |
| Centos6.5x86_64 | DB1 |
Master | essun.mariadb1.com | 192.168.1.109 | 与DB2互为主从 |
| Centos6.5x86_64 | DB2 | Master | essun.mariadb2.com | 192.168.1.112 |
与DB1互为主从 |
| Centos6.5x86_64 | DB3 | Slave | essun.mariadb3.com | 192.168.1.113 |
DB1的从库 |
| Centos6.5x86_64 | Monitor | Monitor | essun.monitor.com | 192.168.1.116 |
监控所有主机 |
虚拟ip(VIP)
DB1 192.168.1.109 `192.168.1.24
DB2 192.168.1.112 192.168.1.24,192.168.1.22
DB3 192.168.1.113 192.168.1.23
三、拓扑图
四、实现过程
1、配置DB1
修改配置文件/etc/my.cnf,添加如下语句
server-id=1 log_bin=/mariadb/data/mysql-bin binlog_format=row log-slave-updates sync_binlog=1 auto_increment_increment=2 auto_increment_offset=1
授权用户
MariaDB [(none)]> grant replication slave,replication client on *.* to 'repluser'@'192.168.1.112' identified by 'replpass'; Query OK, 0 rows affected (0.12 sec) MariaDB [(none)]> grant replication slave,replication client on *.* to 'repluser'@'192.168.1.113' identified by 'replpass'; Query OK, 0 rows affected (0.00 sec)
查看binlog日志标记
MariaDB [(none)]> show master status; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000003 | 756 | | | +------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)
2、配置DB2
修改配置文件/etc/my.cnf,添加如下语句
log-bin=mysql-bin binlog_format=ROW log-slave-updates sync_binlog=1 auto_increment_increment=2 auto_increment_offset=2 server-id=2
授权用户
MariaDB [(none)]> grant replication slave,replication client on *.* to 'repluser'@'192.168.1.109' identified by 'replpass'; Query OK, 0 rows affected (0.15 sec)
查看binlog日志标记
MariaDB [(none)]> show master status; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000007 | 548 | | | +------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)
连接DB1
MariaDB [(none)]> change master to master_host='192.168.1.109',master_user='repluser',master_password='replpass',master_log_file='mysql-bin.000003',master_log_pos=756;
Query OK, 0 rows affected (0.06 sec)
MariaDB [(none)]> start slave;
Query OK, 0 rows affected (0.06 sec)
MariaDB [(none)]> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.1.109
Master_User: repluser
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000003
Read_Master_Log_Pos: 756
Relay_Log_File: essun-relay-bin.000002
Relay_Log_Pos: 535
Relay_Master_Log_File: mysql-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 756
Relay_Log_Space: 832
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: Yes
Master_SSL_CA_File: /etc/slave/cacert.pem
Master_SSL_CA_Path:
Master_SSL_Cert: /etc/slave/mysql.crt
Master_SSL_Cipher:
Master_SSL_Key: /etc/slave/mysql.key
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1
Master_SSL_Crl: /etc/slave/cacert.pem
Master_SSL_Crlpath:
Using_Gtid: No
Gtid_IO_Pos:
1 row in set (0.00 sec)
3、配置DB3
修改配置文件/etc/my.cnf添加如下语句
server-id=3 log-bin=mysql-bin log-slave-updates relay-log=relay-log-bin
连接DB1
MariaDB [(none)]> change master to master_host='192.168.1.109',master_user='repluser',master_password='replpass',master_log_file='mysql-bin.000003',master_log_pos=756;
Query OK, 0 rows affected (0.03 sec)
MariaDB [(none)]> start slave;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.1.109
Master_User: repluser
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000003
Read_Master_Log_Pos: 756
Relay_Log_File: relay-log-bin.000002
Relay_Log_Pos: 535
Relay_Master_Log_File: mysql-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 756
Relay_Log_Space: 830
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: Yes
Master_SSL_CA_File: /etc/slave/cacert.pem
Master_SSL_CA_Path:
Master_SSL_Cert: /etc/slave/mysql.crt
Master_SSL_Cipher:
Master_SSL_Key: /etc/slave/mysql.key
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1
Master_SSL_Crl: /etc/slave/cacert.pem
Master_SSL_Crlpath:
Using_Gtid: No
Gtid_IO_Pos:
1 row in set (0.00 sec)
DB1连接DB2
MariaDB [(none)]> change master to master_host='192.168.1.112',master_user='repluser',master_password='replpass',master_log_file='mysql-bin.000007',master_log_pos=548;
Query OK, 0 rows affected (0.03 sec)
MariaDB [(none)]> start slave;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.1.112
Master_User: repluser
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000007
Read_Master_Log_Pos: 548
Relay_Log_File: essun-relay-bin.000002
Relay_Log_Pos: 535
Relay_Master_Log_File: mysql-bin.000007
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 548
Relay_Log_Space: 832
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 2
Master_SSL_Crl:
Master_SSL_Crlpath:
Using_Gtid: No
Gtid_IO_Pos:
1 row in set (0.00 sec)
4、测试
在DB2中建立一个数据库testdb
MariaDB [mysql]> create database testdb;
Query OK, 1 row affected (0.02 sec)
MariaDB [mysql]> use testdb;
Database changed
MariaDB [testdb]> create table t1 (name char(40) not null,age int not null);
Query OK, 0 rows affected (0.17 sec)
MariaDB [testdb]> insert t1 values ('king',24);
Query OK, 1 row affected (0.01 sec)
在DB1中对testdb，插入一条数据
MariaDB [testdb]> insert t1 values ('tom',24);
Query OK, 1 row affected (0.01 sec)
在DB3中查看结果
MariaDB [(none)]> select * from testdb.t1; +------+-----+ | name | age | +------+-----+ | tom | 24 | | king | 24 | +------+-----+ 2 rows in set (0.00 sec) MariaDB [(none)]>
OK
！
三台DB的主从配置正常工作
5、安装mysql-mmm-agent
在DB1~3上安装mysql-mmmo-agent
注：mysql-mmm-agent是在epel源中，所以要下载EPEL源安装包即可http://download.fedoraproject.org/pub/epel/6/i386/repoview/epel-release.html
下载对应的版本就可以的。
#rpm -ivh epel-release-6-8.noarch.rpm yum -y install mysql-mmm-agent
每一个节点都要安装
在每一个节点上要给Monitor授权用户
MariaDB [(none)]> GRANT SUPER, REPLICATION CLIENT, PROCESS ON *.* TO 'mmm_agent'@'192.168.1.116' IDENTIFIED BY '123456'; Query OK, 0 rows affected (0.01 sec) MariaDB [(none)]> GRANT REPLICATION CLIENT ON *.* TO 'mmm_monitor'@'192.168.1.116' IDENTIFIED BY '123456'; Query OK, 0 rows affected (0.01 sec) MariaDB [(none)]> GRANT REPLICATION CLIENT ON *.* TO 'repluser'@'192.168.1.116' IDENTIFIED BY 'replpass'; Query OK, 0 rows affected (0.01 sec)
6、在Monitor节点上要安装
#yum -y install mysql-mmm*
此包同样也在epel源中
7、在Monitor端的设置/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 repluser #复制用户
replication_password replpass #复制密码
agent_user mmm_agent #代理用户
agent_password 123456 #代理用户的密码
</host>
<host db1>
ip 192.168.1.109
mode master
peer db2
</host>
<host db2>
ip 192.168.1.112
mode master
peer db1
</host>
<host db3>
ip 192.168.1.113
mode slave
</host>
<role writer>
hosts db1, db2
ips 192.168.1.24
mode exclusive #排它
</role>
<role reader>
hosts db2, db3
ips 192.168.1.22, 192.168.1.23
mode balanced #均衡
</role>
将此文件分发到各DB1~3中的/etc/mysql-mmm/下
8、每一个DB中都会有mmm_agent的配置文件，编辑mmm_agent.conf
在数据库服务器上，还有一个mmm_agent.conf需要修改，其内容是：
include mmm_common.conf # The 'this' variable refers to this server. Proper operation requires # that 'this' server (db1 by default), as well as all other servers, have the # proper IP addresses set in mmm_common.conf. this db2
第一行表示：将之前Monitor中的mmm_common.conf文件载入到此文件中，供此文件中的参数设用。
最后一行标记此主机的角色（引用mmm_common.conf中的host段）在不同的数据库服务器上要分别改为db1和db3否则代理就会无法启动。
9、编辑mmm_mon.confg
在Monitor上，修改mmm_mon.conf文件，修改后内容为：
include mmm_common.conf
<monitor>
ip 192.168.1.116 #当前monitor主机地址
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 192.168.1.109, 192.168.1.112 #真实DB地址
auto_set_online 10
# 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 #监控DB的用户名
monitor_password 123456 #密码
</host>
debug 0 #关闭debug功能，如果程序无法监控得到，可以使用debug 1查错
10、启动MMM
在各DB端启动mmm-agent
#/etc/init.d/mysql-mmm-agent start #echo "/etc/init.d/mysql-mmm-agent start" >> /etc/rc.local
在Monitor端启动监控程序
#cd /etc/init.d/ # chkconfig mysql-mmm-monitor on # service mysql-mmm-monitor start
过几秒钟，就可以使用mmm_control show查看在线监控端(DB)了
[root@essun ~]# service mysql-mmm-monitor status mmm_mond (pid 5395) is running... [root@essun ~]# mmm_control show db1(192.168.1.109) master/ONLINE. Roles: db2(192.168.1.112) master/ONLINE. Roles: reader(192.168.1.22), writer(192.168.1.24) db3(192.168.1.113) slave/ONLINE. Roles: reader(192.168.1.23)
注：可以使用
[root@essun ~]# mmm_control --help
Invalid command '--help'
Valid commands are:
help - show this message
ping - ping monitor
show - show status
checks [<host>|all [<check>|all]] - show checks status
set_online <host> - set host <host> online
set_offline <host> - set host <host> offline
mode - print current mode.
set_active - switch into active mode.
set_manual - switch into manual mode.
set_passive - switch into passive mode.
move_role [--force] <role> <host> - move exclusive role <role> to host <host>
(Only use --force if you know what you are doing!)
set_ip <ip> <host> - set role with ip <ip> to host <host>
查看mmm_control的可用参数
11、模拟DB2下线
Monitor当前状态
让DB2下线，当前可写主机是db1,db3
db2没有下线之前还可以读写，当下线之后，可写的切换到DB1上了，所有读的都到了db3上了
当DB2重新上线后的情况如下
注：DB1、DB同时只能一有个写，一个读！
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