目录

• 一.理论概述
  • 组件介绍
• 三.部署
• 四.测试
• 五.总结

preface:

MMM架构相比于MHA来说各方面都逊色不少,写这篇案例也算是整理下思路吧.

一.理论概述

MMM(Master-Master replication Manager for MySQL)
是一套支持双主日常管理的脚本程序,使用Perl语言开发,主要用来监控和管理MySQL双主库复制,同一时刻只允许一个主库进行写入

方便的是,mmm不但可以为写库配置VIP,而且实现读库VIP,也可以节省一些构建读负载均衡及高可用的资源

实现的功能简单来说就是实现了主库的故障切换功能,同时也可以实现多个slave读操作的负载均衡

不适用的场景:对数据一致性要求很高不适用

组件介绍

1. mmm-mond程序:监控进程,负责所有的监控工作,在管理服务器上运行
2. mmm_agentd:运行在每个集群mysql节点上的,完成监控的探针工作和执行简单的远端服务设置

3. mmm_control：一个简单的管理脚本，用来查看和管理集群运行状态，同时管理mmm_mond进程。

   二.环境

• 架构拓扑,本案例只针对于数据库集群示范
  

实现思路:先部署主主高可用,安装mmm相关组件

三.部署

• 所有主机安装epel源

<code>下载地址
https://mirrors.tuna.tsinghua.edu.cn/epel//
然后选择相应的版本下载并安装
yum clean all && yum makecache </code>

• 基本环境

<code>[root@localhost ~]# vim /etc/hosts
192.168.111.3   master
192.168.111.4   masterba
192.168.111.5   slave1
192.168.111.6   slave2
[root@localhost ~]# hostname master
[root@localhost ~]# bash
[root@master ~]# bash
[root@master ~]# uname -n
master
#全部修改为对应的</code>

• 部署二进制包mysql5.7.24

<code>yum -y install libaio
wget http://mirrors.sohu.com/mysql/MySQL-5.7/mysql-5.7.24-linux-glibc2.12-x86_64.tar.gz
useradd -M -s /sbin/nologin mysql
tar zxf mysql-5.7.24-linux-glibc2.12-x86_64.tar.gz 
mv mysql-5.7.24-linux-glibc2.12-x86_64 /usr/local/mysql
chown -R mysql:mysql /usr/local/mysql
ln -s /usr/local/mysql/bin/* /usr/local/bin/
cp /usr/local/mysql/support-files/mysql.server /etc/init.d/mysqld
mysqld --user=mysql --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data --initialize
#记住生成的随机密码待会启动服务之后修改
vim /etc/my.cnf
--------------------111.3--------------------------
[mysqld]
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
symbolic-links=0
server-id=1
log-bin=mysql-bin
log_slave_updates=1
#将另一台备主同步数据给自身时,写入到binarylog
auto-increment-increment=2
auto-increment-offset=1
#auto_increment_increment：自增值
#auto_increment_offset：漂移值,也就是步长
[mysqld_safe]
log-error=/usr/local/mysql/data/mysql.log
pid-file=/usr/local/mysql/data/mysql.pid
!includedir /etc/my.cnf.d
--------------------111.4--------------------------
[mysqld]
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
symbolic-links=0
server-id=2
log-bin=mysql-bin
log_slave_updates=1
#将另一台备主同步数据给自身时,写入到binarylog
auto-increment-increment=2
auto-increment-offset=2
#auto_increment_increment：自增值
#auto_increment_offset：漂移值,也就是步长
[mysqld_safe]
log-error=/usr/local/mysql/data/mysql.log
pid-file=/usr/local/mysql/data/mysql.pid
!includedir /etc/my.cnf.d
--------------------111.5--------------------------
[mysqld]
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
symbolic-links=0
server-id=3
log-bin=mysql-bin
log_slave_updates=1
[mysqld_safe]
log-error=/usr/local/mysql/data/mysql.log
pid-file=/usr/local/mysql/data/mysql.pid
!includedir /etc/my.cnf.d
--------------------111.6--------------------------
[mysqld]
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
symbolic-links=0
server-id=4
log_slave_updates=1
log-bin=mysql-bin
[mysqld_safe]
log-error=/usr/local/mysql/data/mysql.log
pid-file=/usr/local/mysql/data/mysql.pid
!includedir /etc/my.cnf.d
[root@masterba ~]# /etc/init.d/mysqld start
[root@master ~]# mysqladmin -u root -p'BZn9B++V06qg' password '123456' 
mysqladmin: [Warning] Using a password on the command line interface can be insecure.
Warning: Since password will be sent to server in plain text, use ssl connection to ensure password safety.
#修改默认密码</code>

• 部署主主同步

<code>--master:
[root@master ~]# mysql -u root -p123456
mysql> grant replication slave on *.* to 'myslave'@'192.168.111.%' identified by'123456';
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000002 |      879 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
--masterba:
[root@masterba ~]# mysql -uroot -p123456
mysql> grant replication slave on *.* to 'myslave'@'192.168.111.%' identified by'123456';
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000002 |      879 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
--master:
mysql> change master to master_host='192.168.111.4',master_user='myslave',master_password='123456',master_log_file='mysql-bin.000002',master_log_pos=879;
Query OK, 0 rows affected, 2 warnings (0.11 sec)
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.111.4
                  Master_User: myslave
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000002
          Read_Master_Log_Pos: 879
               Relay_Log_File: master-relay-bin.000002
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql-bin.000002
             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: 879
              Relay_Log_Space: 528
              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_UUID: 01008194-68b1-11e9-bf0b-000c294b0234
             Master_Info_File: /usr/local/mysql/data/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)
--masterba:
mysql> change master to master_host='192.168.111.3',master_user='myslave',master_password='123456',master_log_file='mysql-bin.000002',master_log_pos=879;
Query OK, 0 rows affected, 2 warnings (0.01 sec)
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.111.3
                  Master_User: myslave
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000002
          Read_Master_Log_Pos: 1036
               Relay_Log_File: masterba-relay-bin.000002
                Relay_Log_Pos: 477
        Relay_Master_Log_File: mysql-bin.000002
             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: 1036
              Relay_Log_Space: 687
              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: 1
                  Master_UUID: e13f8b12-7bda-11e9-b71b-000c2935c4a6
             Master_Info_File: /usr/local/mysql/data/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)
slave1:
mysql> change master to master_host='192.168.111.4',master_user='myslave',master_password='123456',master_log_file='mysql-bin.000002',master_log_pos=879;
Query OK, 0 rows affected, 2 warnings (0.02 sec)
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
#slave2一样操作,一同指向masterba
</code>

• 部署mmm

<code>我们在主库上做授权,由于现在是同步状态,所以授权信息其它数据库也会存在
mysql> grant replication client on *.* to 'mmm_monitor'@'192.168.111.%' identified by '123456';
Query OK, 0 rows affected, 1 warning (0.11 sec)
#监控用户
mysql> grant super,replication client,process on *.* to 'mmm_agent'@'192.168.111.%' identified by '123456';
Query OK, 0 rows affected, 1 warning (0.01 sec)
#agent用户
mysql> grant replication slave on *.* to 'myslave'@'192.168.111.%' identified by '123456';
Query OK, 0 rows affected, 1 warning (0.00 sec)
#复制用户
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
[root@slave2 ~]# vim /etc/mysql-mmm/mmm_common.conf 
#该文件所有节点配置都相同
active_master_role      writer
<host default>
    cluster_interface       ens32
    pid_path                /run/mysql-mmm-agent.pid
    bin_path                /usr/libexec/mysql-mmm/
    replication_user        myslave
    replication_password    123456
    agent_user              mmm_agent
    agent_password          123456
    #刚才所授权用户的账号及密码
</host>
<host db1>
    ip      192.168.111.3
    mode    master
    peer    db2
</host>
<host db2>
    ip      192.168.111.4
    mode    master
    peer    db1
</host>
<host db3>
    ip      192.168.111.5
    mode    slave
</host>
<host db4>
    ip      192.168.111.6
    mode    slave
</host>
#每个host是一个节点,按照文件格式配置
<role writer>
    hosts   db1, db2
    ips     192.168.111.100
    #写操作服务器的VIP
    mode    exclusive
    #模式:同意时间只有一个节点可以使用资源
</role>
<role reader>
    hosts   db3, db4
    ips     192.168.111.200
    #读操作服务器的VIP,可以有多个,逗号分隔
    mode    balanced
    #负载均衡模式
</role>
[root@slave2 ~]# scp /etc/mysql-mmm/mmm_common.conf root@master:/etc/mysql-mmm/
[root@slave2 ~]# scp /etc/mysql-mmm/mmm_common.conf root@masterba:/etc/mysql-mmm/
[root@slave2 ~]# scp /etc/mysql-mmm/mmm_common.conf root@slave1:/etc/mysql-mmm/
在db1-4上修改mmm_agent.conf，只需要修改db1这里，是哪台就改成哪台，这里只给出db1的
[root@master ~]# vim /etc/mysql-mmm/mmm_agent.conf 
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 db1
配置监控工作的服务器
[root@slave2 ~]# vim /etc/mysql-mmm/mmm_mon.conf 
  8     ping_ips            192.168.111.2
  #测试网络可用性的IP地址,一般指定网关
  9     auto_set_online     60
  #是否设置自动上线，如果该值大于0，抖动的主机在抖动的时间范围过后，则设置自动上线
 20     monitor_user        mmm_monitor
 21     monitor_password    123456
  #监控的用户和密码
全部节点启动agent
[root@master ~]# systemctl start mysql-mmm-agent.service 
[root@master ~]# systemctl status mysql-mmm-agent.service 
监控机器启动monitor
[root@slave2 ~]# systemctl start mysql-mmm-monitor.service 
[root@slave2 ~]# systemctl status mysql-mmm-monitor.service 
#检查集群状态,要全部是ONLINE才正确
[root@slave2 ~]# mmm_control show
  db1(192.168.111.3) master/ONLINE. Roles: writer(192.168.111.100)
  db2(192.168.111.4) master/ONLINE. Roles: 
  db3(192.168.111.5) slave/ONLINE. Roles: reader(192.168.111.200)
  db4(192.168.111.6) slave/ONLINE. Roles: </code>

四.测试

• 查看VIP是否正确分配

<code>写:
[root@master ~]# ip a| grep ens32
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    inet 192.168.111.3/24 brd 192.168.111.255 scope global noprefixroute ens32
    inet 192.168.111.100/32 scope global ens32
读:
[root@slave1 ~]# ip a| grep ens32
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    inet 192.168.111.5/24 brd 192.168.111.255 scope global noprefixroute ens32
    inet 192.168.111.200/32 scope global ens32</code>

• 测试VIP转移

<code>[root@master ~]# /etc/init.d/mysqld stop
Shutting down MySQL............ SUCCESS! 
[root@master ~]# ip a| grep ens32
-----写-----
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    inet 192.168.111.3/24 brd 192.168.111.255 scope global noprefixroute ens32
[root@masterba ~]# ip a| grep ens32
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    inet 192.168.111.4/24 brd 192.168.111.255 scope global noprefixroute ens32
    inet 192.168.111.100/32 scope global ens32
-----读-----
[root@slave1 ~]# /etc/init.d/mysqld stop
Shutting down MySQL.... SUCCESS! 
[root@slave1 ~]# ip a| grep ens32
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    inet 192.168.111.5/24 brd 192.168.111.255 scope global noprefixroute ens32
    inet 192.168.111.200/32 scope global ens32
[root@slave1 ~]# ip a| grep ens32
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    inet 192.168.111.5/24 brd 192.168.111.255 scope global noprefixroute ens32
    inet 192.168.111.200/32 scope global ens32
[root@slave1 ~]# ip a| grep ens32
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    inet 192.168.111.5/24 brd 192.168.111.255 scope global noprefixroute ens32
    inet 192.168.111.200/32 scope global ens32
[root@slave1 ~]# ip a| grep ens32
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    inet 192.168.111.5/24 brd 192.168.111.255 scope global noprefixroute ens32
[root@slave2 ~]# ip a| grep ens32
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    inet 192.168.111.6/24 brd 192.168.111.255 scope global noprefixroute ens32
    inet 192.168.111.200/32 scope global ens32
#切换的慢
[root@slave2 ~]# mmm_control show
  db1(192.168.111.3) master/HARD_OFFLINE. Roles: 
  db2(192.168.111.4) master/ONLINE. Roles: writer(192.168.111.100)
  db3(192.168.111.5) slave/HARD_OFFLINE. Roles: 
  db4(192.168.111.6) slave/ONLINE. Roles: reader(192.168.111.200)
#离线的已经指明了</code>

• 修复好的数据库服务器重新加入集群的方法

<code>[root@master ~]# /etc/init.d/mysqld start
#登上两三分钟最多,比较慢,在monitor上查看状态
[root@slave2 ~]# mmm_control show
  db1(192.168.111.3) master/ONLINE. Roles: 
  db2(192.168.111.4) master/ONLINE. Roles: writer(192.168.111.100)
  db3(192.168.111.5) slave/HARD_OFFLINE. Roles: 
  db4(192.168.111.6) slave/ONLINE. Roles: reader(192.168.111.200)</code>

• 连接数据库VIP测试

<code>mysql> grant all privileges on *.* to root@'192.168.111.%' identified by '123456';
Query OK, 0 rows affected, 1 warning (0.01 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.10 sec)
#主库上做下授权,从库也会同步授权信息
[root@slave2 ~]# mysql -uroot -p123456 -h'192.168.111.100'
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 415
Server version: 5.7.24-log MySQL Community Server (GPL)
Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> 
[root@slave2 ~]# mysql -uroot -p123456 -h'192.168.111.200'
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1043
Server version: 5.7.24-log MySQL Community Server (GPL)
Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> 
#输入的必须都是VIP进行连接</code>

五.总结

1. 明显的切换速度太慢,案例环境还是没有多少数据的,以及系统环境也不是很复杂,生产环境慎用吧
2. 可以做写的高可用,也可以用来负载均衡读的服务器
3. 持之以恒

Mysql高可用集群-解决MMM单点故障

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