利用keepalived构建高可用MySQL High Application

      关于MySQL-HA，目前有多种解决方案，比如heartbeat、drbd、mmm、共享存储，但是它们各有优缺点。heartbeat、 drbd配置较为复杂，需要自己写脚本才能实现MySQL自动切换；对于mmm，生产环境中很少有人 用，且mmm 管理端需要单独运行一台服务器上，要是想实现高可用，就得对mmm管理端做HA，这样无疑又增加了硬件开支；对于共享存储，个人觉得MySQL数据还是放 在本地较为安全，存储设备毕竟存在单点隐患。

　　使用MySQL双master+keepalived是一种非常好的解决方案，在MySQL-HA环境中，MySQL互为主从关系，这样就保证 了两台MySQL数据的一致性，然后用keepalived实现虚拟IP，通过keepalived自带的服务监控功能来实现MySQL故障时自动切换。

　　下面是MySQL-HA是实现方式：

一、环境

MySQL-VIP：10.0.5.76 MySQL-master1：10.0.5.41 MySQL-master2：10.0.5.75 OS版本：ubuntu 14.04 LTS MySQL版本：5.5.43 Keepalived版本：v1.2.7 (08/14,2013)

二、Mysql Master to Master 配置

　　1、配置MySQL-master1：10.0.5.41

　　　　a) 修改mysql配置文件

vim /etc/mysql/my.cnf user = mysql log-bin=mysql-bin server-id=1 binlog-ignore-db=mysql replicate-ignore-db=mysql,information_schema sync_binlog=1 auto_increment_offset=1 auto_increment_increment=2 slave-skip-errors=all 

　　　　b) 新建授权用户

/etc/init.d/mysql restart mysql>CREATE USER 'replication'IDENTIFIED BY '123456'; mysql>grant replication slave on *.* to 'replication'@'10.0.5.75' identified by '123456' with grant option; mysql> show master status \G *************************** 1. row *************************** File: mysql-bin.000032 Position: 107 Binlog_Do_DB: Binlog_Ignore_DB: mysql 1 row in set (0.00 sec)

　　　　c) 将10.0.5.75设置为10.0.5.41的主服务器

mysql>stop slave; mysql>change master to master_host='10.0.5.75',master_user='replication',master_password='123456', master_log_file='mysql-bin.000006',master_log_pos=107; mysql>start slave; mysql> show slave status\G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 10.0.5.75 Master_User: replication Master_Port: 3306 Connect_Retry: 60 Master_Log_File: mysql-bin.000019 Read_Master_Log_Pos: 107 Relay_Log_File: mysqld-relay-bin.000002 Relay_Log_Pos: 333 Relay_Master_Log_File: mysql-bin.000006 Slave_IO_Running: Yes Slave_SQL_Running: Yes Replicate_Do_DB: Replicate_Ignore_DB: mysql,information_schema 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: 187 Relay_Log_Space: 490 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

　　2、配置MySQL-master2：10.0.5.75

　　　　a) 修改配置文件

vim /etc/mysql/my.cnf user = mysql log-bin=mysql-bin server-id=2 binlog-ignore-db=mysql replicate-ignore-db=mysql,information_schema sync_binlog=1 auto_increment_offset=2 auto_increment_increment=2 slave-skip-errors=all 

　　    b) 新建授权用户

/etc/init.d/mysql restart mysql>CREATE USER 'replication'IDENTIFIED BY '123456'; mysql>grant replication slave on *.* to 'replication'@'10.0.5.41' identified by '123456' with grant option; mysql> show master status\G *************************** 1. row *************************** File: mysql-bin.000019 Position: 107 Binlog_Do_DB: Binlog_Ignore_DB: mysql 1 row in set (0.00 sec)

　　　  c) 将10.0.5.41设置为10.0.5.75的主服务器

mysql>stop slave; mysql>change master to master_host='10.0.5.41',master_user='replication',master_password='123456', master_log_file='mysql-bin.000006',master_log_pos=107; mysql>start slave; mysql> show slave status\G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 10.0.5.41 Master_User: replication Master_Port: 3306 Connect_Retry: 60 Master_Log_File: mysql-bin.000032 Read_Master_Log_Pos: 107 Relay_Log_File: mysqld-relay-bin.000002 Relay_Log_Pos: 333 Relay_Master_Log_File: mysql-bin.000010 Slave_IO_Running: Yes Slave_SQL_Running: Yes Replicate_Do_DB: chris,ian Replicate_Ignore_DB: mysql,information_schema Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 0Exec_Master_Log_Pos: 187 Relay_Log_Space: 490 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

　　3、MySQL同步测试

　　 如上述均正确配置，现在任何一台MySQL上更新数据都会同步到另一台MySQL。

三、配置keepalived

　　1、在10.0.5.41上配置keepalived

apt-get install keepalived vim /etc/keepalived/keepalived.conf # Global Configuration global_defs { router_id MySQL-ha } # VRRP Configuration vrrp_instance VI_1 { state BACKUP interface eth0 virtual_router_id 51 priority 90 advert_int 1 authentication { auth_type PASS auth_pass root } virtual_ipaddress { 10.0.5.76 # * VIP } } # Virtual Server Configuration virtual_server 10.0.5.76 3306 { delay_loop 2 lb_algo wrr lb_kind DR persistence_timeout 60 protocol TCP # Real Server 1 configuration real_server 10.0.5.41 3306 { weight 3 notify_down /etc/keepalived/kill_keepalived.sh TCP_CHECK { connection_timeout 10 nb_get_retry 3 delay_before_retry 3 connect_port=3306 } } }

　　编写检测服务down后所要执行的脚本

vim  /etc/keepalived/kill_keepalived.sh #!/bin/sh pkill keepalived chmod +x /etc/keepalived/kill_keepalived.sh

/etc/init.d/keepalived start

　　注：此脚本是上面配置文件notify_down选项所用到的，keepalived使用notify_down选项来检查real_server的服务状态，当发现real_server服务故障时，便触发此脚本；我们可以看到，脚本就一个命令，通过pkill keepalived强制杀死keepalived进程，从而实现了MySQL故障自动转移。另外，我们不用担心两个MySQL会同时提供数据更新操作， 因为每台MySQL上的keepalived的配置里面只有本机MySQL的IP+VIP，而不是两台MySQL的IP+VIP。

　　2、在10.0.5.75上配置keepalived

apt-get install keepalived vim /etc/keepalived/keepalived.conf # Global Configuration global_defs { router_id MySQL-ha } # VRRP Configuration vrrp_instance VI_1 { state MASTER interface eth0 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass root } virtual_ipaddress { 10.0.5.76 # * VIP } } # Virtual Server Configuration virtual_server 10.0.5.76 3306 { delay_loop 2 lb_algo wrr lb_kind DR persistence_timeout 60 protocol TCP # Real Server 1 configuration real_server 10.0.5.75 3306 { weight 3 notify_down /etc/keepalived/kill_keepalived.sh TCP_CHECK { connection_timeout 10 nb_get_retry 3 delay_before_retry 3 connect_port=3306 } } }

　　编写检测服务down后所要执行的脚本

vim  /etc/keepalived/kill_keepalived.sh #!/bin/sh pkill keepalived chmod +x /etc/keepalived/kill_keepalived.sh 

/etc/init.d/keepalived start

　　停止MySQL服务，看keepalived健康检查程序是否会触发我们编写的脚本。

四、测试

　　MySQL远程登录测试，选择一台内网机器10.0.5.74远程登录VIP，看是否能登录，在登录之前两台MySQL服务器都要授权允许从远程登录。

MySQL> grant all privileges on *.* to 'root'@'%' identified by 'root'; MySQL> flush privileges;  

　　远程登录测试

mysql -uroot -proot -h 10.0.5.76 Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 10818 Server version: 5.5.43-0ubuntu0.14.04.1-log (Ubuntu) Copyright (c) 2000, 2015, 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>

　　keepalived故障转移测试

　　从10.0.5.74一直去ping  VIP，然后关闭10.0.5.41上的keepalived，正常情况下VIP就会切换到10.0.5.75上面去

　　开启10.0.5.75上的keepalived，关闭10.0.5.41上的keepalived，看是否能自动切换，正常情况下VIP又会属于10.0.5.41

　　 MySQL故障转移测试

　　在10.0.5.41上关闭MySQL服务，看VIP是否会切换到10.0.5.75上

　　开启10.0.5.41上的MySQL和keepalived，然后关闭10.0.5.75上的MySQL，看VIP是否会切换到10.0.5.41上