编译安装keepalived，实现双主mysql高可用

安装keepalived

1、官网下载源码包，解压

# wget http://www.keepalived.org/software/keepalived-1.1.20.tar.gz
# tar xvf keepalived-1.1.20.tar.gz

2、编译安装，这里需要指定一下安装路径

# cd keepalived-1.1.20/
# ./configure --prefix=/usr/local/keepalived
# make && make install

3、拷贝配置文件和启动脚本到相应的目录

# mkdir /etc/keepalived
# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf
# cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/

4、设置开机启动

# chkconfig keepalived on

配置mysql双主

所谓双主，即两个节点互为主从，各自把对方设为master，两个节点都需要开启binlog和relaylog。

两个节点server_id必须不一样。

由于两个节点都可写，为了保证自增主键ID不冲突，需要设置 auto_increment_offset 和 auto_increment_increment。

主从复制过程：

a、master将改变记录到二进制日志（binlog）中；

b、slave将master的binlog拷贝到它的中继日志（relaylog）；

c、slave重做中继日志中的事件，将改变反映到它自己的数据库。

① slave将master的binary log拷贝到它自己的中继日志。

② I/O线程在master上打开一个普通的连接，然后开始binlog dump process。Binlog dump process从master的二进制日志中读取事件，如果已经跟上master，它会睡眠并等待master产生新的事件。I/O线程将这些事件写入中继日志。

③ SQL线程从中继日志读取事件，并重放其中的事件而更新slave的数据，使其与master中的数据一致。

1、修改节点一的配置文件

# vim /etc/my.cnf
server-id=1
datadir=/nh/mysql3307/data
log-bin=/nh/mysql3307/data
log-bin-index=/nh/mysql3307/data
relay_log=relay-log
auto_increment_offset=1
auto_increment_increment=2
innodb_file_per_table=1

# /etc/init.d/mysqld start

2、修改配置节点二的配置文件

# vim /etc/my.cnf
server-id=2
datadir=/nh/mysql3307/data
log-bin=/nh/mysql3307/data
log-bin-index=/nh/mysql3307/data
relay_log=relay-log
auto_increment_offset=2
auto_increment_increment=2
innodb_file_per_table=1

# /etc/init.d/mysqld start

3、登录节点一的mysql，设置有复制权限的账号

# mysql -uroot -S mysql-3307.sock
mysql> grant replication slave,replication client on *.* to repl@'192.168.%' identified by 'Fl0wer926';
mysql> flush privileges;

查看当前正在使用的binlog文件和所在位置

mysql> show master status;
+-------------+----------+--------------+------------------+
| File        | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+-------------+----------+--------------+------------------+
| data.00005  |      106 |              |                  |
+-------------+----------+--------------+------------------+

登录节点二的mysql，将节点一设置为其master

mysql> change master to master_host='192.168.1.101',MASTER_PORT = 3307,master_user='repl',master_password='Fl0wer926',master_log_file='data.000005',master_log_pos=106;
mysql> start slave;

mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.1.101
                  Master_User: repl
                  Master_Port: 3307
                Connect_Retry: 60
              Master_Log_File: data.000010
          Read_Master_Log_Pos: 106
               Relay_Log_File: relay-log.000021
                Relay_Log_Pos: 246
        Relay_Master_Log_File: data.000010
             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: 106
              Relay_Log_Space: 535
              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:
1 row in set (0.00 sec)

mysql> show processlist;
+-------+-------------+---------------------+------+-------------+-------+-----------------------------------------------------------------------+------------------+
| Id    | User        | Host                | db   | Command     | Time  | State                                                                 | Info             |
+-------+-------------+---------------------+------+-------------+-------+-----------------------------------------------------------------------+------------------+
|     7 | system user |                     | NULL | Connect     | 43454 | Waiting for master to send event                                      | NULL             |
|     8 | system user |                     | NULL | Connect     | 36323 | Has read all relay log; waiting for the slave I/O thread to update it | NULL             |
| 33612 | repl        | 192.168.1.101:57914 | NULL | Binlog Dump |   967 | Has sent all binlog to slave; waiting for binlog to be updated        | NULL             |
| 34514 | root        | localhost           | NULL | Query       |     0 | NULL                                                                  | show processlist |
+-------+-------------+---------------------+------+-------------+-------+-----------------------------------------------------------------------+------------------+

交换两个节点的角色重复一次以上操作，即可实现主主复制。

4、修改节点一的keepalived配置文件

# vim /etc/keepalived/keepalived.conf
global_defs {
   router_id MYSQL_MM
}

vrrp_script chk_mysqld3307 {
    script "nc 192.168.1.101 3307"
    interval 1
    weight -10
    fall 2
    rise 1
}

vrrp_instance VI_1 {
    state MASTER
    interface bond0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1234
    }
    virtual_ipaddress {
        192.168.6.12
    }
    track_script {
        chk_mysqld3307
    }
}

# /etc/init.d/keepalived start

5、修改节点二的keepalived配置文件

# vim /etc/keepalived/keepalived.conf
global_defs {
   router_id MYSQL_MM
}

vrrp_script chk_mysqld3307 {
    script "nc 192.168.1.102 3307"
    interval 1
    weight -10
    fall 2
    rise 1
}

vrrp_instance VI_1 {
    state BACKUP
    interface bond0
    virtual_router_id 51
    priority 95
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1234
    }
    virtual_ipaddress {
        192.168.6.12
    }
    track_script {
        chk_mysqld3307
    }
}

# /etc/init.d/keepalived start

至此，通过keepalived实现mysql双主高可用就完成了，然后可以尝试停止vip所在节点测试vip是否会自动漂移，然后再把节点启动看vip是否会被抢占回来。