最近在做MySQL数据库的双向主从，了解到keepalived能够自动判断并切换到可用数据库，自己试了一下，整理出文档来。
先声明一下环境
iptables开启3306端口或者关掉，关闭selinux
MySQL-01：192.168.204.138
MySQL-02：192.168.204.139
VIP：192.168.204.200 #web服务器连接的ip，自己可以使用工具连接试一下。
MySQL的安装过程就略过了，根据个人情况自己安装即可。
1.修改数据库的配置文件/etc/my.cnf：
1.1修改MySQL-01的数据库文件,在[mysql]下添加如下内容server_id = 1
log_bin = mysql-bin
1.2修改MySQL-02的数据库文件,在[mysql]下添加如下内容server_id = 2
log_bin = mysql-bin
2.搭建单向主从
2.1在MySQL-01上
2.1.1操作授权mysql -u root -p #输入密码
mysql> grant replication slave on *.* to 'slave'@'192.168.204.139' identified by '123456';
mysql> flush privileges;
2.1.2数据传递给MySQL-02mysql -u root -p #输入密码
flush tables with read lock; #锁表操作
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000012 | 120 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
mysqldump -u root -p --all-databases > mysqldump.sql
mysql -u root -p
mysql> unlock tables;
mysql> quit
scp myqsldump.sql 192.168.204.139:/root/
2.2在MySQL-02上操作
2.2.1恢复数据库数据mysql -u root -p
2.2.2建立主从同步mysql -u root -p
mysql> change master to master_host='192.168.204.138',master_user='slave',master_password='123456',master_log_file='mysql-bin.000012',master_log_pos=120，master_port=3306;
start slave；
检查是否成功show slave status\G；Slave_IO_Running: Yes
Slave_SQL_Running: Yes
都为Yes表示同步成功。
注：master_port=3306,默认时不需要加，但是修改过端口的则需要该选项
3.搭建互为主从
3.1在MySQl-01上操作
3.1.1用户授权mysql -u root -p123456
mysql> grant replication slave on *.* to 'slave'@'192.168.204.138' identified by '123456'; //建立权限
mysql> flush privileges;
注：因为做的是所有库的主从，所以在MySQL-01上的操作会同步到MySQL-02上
注2：假如你是线上环境，主库在不断的写数据，建议锁一下表，最好找个夜深人静的时候做吧
3.2在MySQL-02上的操作mysql -u root -p
mysql> show master status\G;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000009 | 120 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
3.1.2在MySQL-01上操作授权mysql> change master to master_host='192.168.204.138',master_user='slave',master_password='123456',master_log_file='mysql-bin.000009',master_log_pos=120;
mysql> start slave;
检查是否成功show slave status\G；
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
表示成功。
此，mysql的双向主从同步已完成
4.keepalived的搭建
4.1在两台服务器依次做以下操作
a.安装keepalivedwget http://www.keepalived.org/software/keepalived-1.2.15.tar.gz
tar zxvf keepalived-1.2.15.tar.gz
cd keepalived-1.2.15
./configure --prefix=/usr/local/keepalived
make && make install
假如编译过程出现错误，请安装 gcc，openssl，openssl-devel
b.复制相关文件cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
mkdir /etc/keepalived/
cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
4.2修改配置文件
请先将/etc/keepalived/keepalived.conf文件清空
4.2.1在MySQL-01上操作
将一下内容复制进去! Configuration File for keepalived
global_defs {
notification_email {
sunyuansheng7@gmail.com
}
notification_email_from sunyuansheng7@gmail.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id MySQL-ha
}
vrrp_instance VI_1 {
state master
interface eth0
virtual_router_id 51
priority 100
advert_int 1
nopreempt
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.204.222
}
}
virtual_server 192.168.204.222 3306 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 50
protocol TCP
real_server 192.168.204.138 3306 {
weight 3
notify_down /var/lib/mysql/killkeepalived.sh
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
}
4.2.2在MySQL-02上操作
vim /etc/keepalived/keepalived.conf! Configuration File for keepalived
global_defs {
notification_email {
sunyuansheng7@gmail.com
}
notification_email_from sunyuansheng7@gmail.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id MySQL-ha
}
vrrp_instance VI_1 {
state backup
interface eth0
virtual_router_id 51
priority 100
advert_int 1
nopreempt
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.204.222
}
}
virtual_server 192.168.204.222 3306 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 50
protocol TCP
real_server 192.168.204.139 3306 {
weight 3
notify_down /var/lib/mysql/killkeepalived.sh
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
}
4.3在两台服务器做以下操作vim /var/lib/mysql/killkeepalived.sh
#!/bin/sh
pkill keepalived
chmod +x /var/lib/mysql/killkeepalived.sh
4.4此时先不要启动keepalived，因为我们要观察日志
5.测试是否可用
创建一个新的用户mysql> grant all privileges on *.* to 'test'@'%' identified by '123456';
mysql> flush privileges;
5.1在MySQL-01上多开一个终端，tailf /var/log/messages,然后再另一个终端启动keepalived服务service keepalived start。日志信息如下
5.2在MySQL-02同样打开一个新的终端查看日志信息,然后启动keepalived
5.3在MySQL-01上手动停掉MySQL服务。同时得到日志信息
连接3306端口失败，准备移除虚拟ip，然后停掉keepalived服务。最后虚拟ip地址移除。
MySQL-02日志信息没啥变化！话说两边启动keepalived的日志信息差不多是一样的。
此时可以使用连接MySQL的工具测试一下，虚拟ip地址还是可用的。
5.4假设MySQL-01恢复此时还应该启动keepalived服务。
