keepalive配置mysql自动故障转移
本文先配置了一个双master环境，互为主从，然后通过Keepalive配置了一个虚拟IP，客户端通过虚拟IP连接master1,当master1宕机，自动切换到master2。一次只能连接其中一个master进行读写，所以是active-passive模式。
一 Mysql主主复制搭建
1.1 实验环境
两台机器事先都已经装好了mysql单实例。
二者的端口号需要保持一致，否则在最后用vip连接的时候，不能使用相同端口号连接。
1.2 实验步骤
1.2.1 修改配置文件
修改master1：
在[mysqld]下面添加：
server-id = 1
relay-log=/data/server/mysql_3307/binlog/ZabbixServer-relay-bin
relay-log-index=/data/server/mysql_3307/binlog/ZabbixServer-relay-bin.index
auto-increment-offset = 1
auto-increment-increment = 2
log-slave-updates=true
修改master2：
在[mysqld]下面添加：
server-id = 3
relay-log =/data/server/mysql/binlog/single-relay-bin
relay-log-index=/data/server/mysql/binlog/single-relay-bin.index
auto-increment-offset = 2
auto-increment-increment = 2
log-slave-updates=true
添加auto-increment-offset那两项,是为了避免在MySQL INSERT时主键冲突。
修改完后记得重启mysql
1.2.2 建复制用户
分别在两台mysql上执行
GRANT REPLICATION SLAVE ON *.* TO 'RepUser'@'%'identified by 'beijing';
1.2.3 指向master
两台服务器均为新建立，且无其它写入操作，各服务器只需记录当前自己二进制日志文件及事件位置，以之作为另外的服务器复制起始位置即可。否则，需要先备份主库，在备库进行恢复，从而保持数据一致，然后再指向master。
Master1:
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 302| | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
Master2:
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 120 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
#Master1指向Master2
- CHANGE MASTER TO MASTER_USER='RepUser',MASTER_HOST='192.168.1.21',MASTER_PASSWORD='beijing',MASTER_PORT=3307,MASTER_LOG_FILE='mysql-bin.000001',MASTER_LOG_POS=120;
#Master2指向Master1
- CHANGE MASTER TO MASTER_USER='RepUser',MASTER_HOST='192.168.1.22',MASTER_PASSWORD='beijing', MASTER_PORT=3307,MASTER_LOG_FILE='mysql-bin.000001',MASTER_LOG_POS=302;
1.2.4 分别启动slave
start slave ;
确保show slave status
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
测试两边是否同步，略。
二：配置keepalived
1 keepalive安装
分别在master1，master2上安装keepalive
- yum install -y popt-devel
- cd /usr/local/src
- wget http://www.keepalived.org/software/keepalived-1.2.2.tar.gz
- tar zxvf keepalived-1.2.2.tar.gz
- cd keepalived-1.2.2
- ./configure --prefix=/
- make
- make install
#假如在执行./configure --prefix=/时报错： OpenSSL is not properly installed on your system !!!Can notinclude OpenSSL headers files，则yum install openssl-devel -y
2 分别在master1，master2上新建检查mysql脚本
vi /root/check_mysql.sh
内容如下
- MYSQL=/usr/local/mysql/bin/mysql
- MYSQL_HOST=localhost
- MYSQL_USER=root
- MYSQL_PASSWORD=system@123
- $MYSQL -h $MYSQL_HOST -u $MYSQL_USER -p$MYSQL_PASSWORD -e "show status;" >/dev/null 2>&1
- #$mysqlclient --host=$host --port=$port --user=$user --password=$password -e "show databases;" > /dev/null 2>&1
- if [ $? == 0 ]
- then
- echo " $host mysql login successfully "
- exit 0
- else
- #echo " $host mysql login faild"
- /etc/init.d/keepalived stop
- exit 2
- fi
chmod +x /root/check_mysql.sh
3 修改配置文件
vi /etc/keepalived/keepalived.conf
master1和master2配置文件内容相同。
内容：
- #ConfigurationFile for keepalived
- global_defs {
- notification_email { ######定义接受邮件的邮箱
- wangjj@hrloo.com
- }
- notification_email_from jiankong@staff.tuge.com ######定义发送邮件的邮箱
- smtp_server mail.tuge.com
- smtp_connect_timeout 10
- }
- vrrp_script check_mysql { ######定义监控mysql的脚本
- script "/root/check_mysql.sh"
- interval 2 ######监控时间间隔
- weight 2 ######负载参数
- }
- vrrp_instance vrrptest { ######定义vrrptest实例
- state BACKUP ######服务器状态
- interface eth0 ######使用的接口
- virtual_router_id 51 ######虚拟路由的标志，一组lvs的虚拟路由标识必须相同，这样才能切换
- priority 150 ######服务启动优先级，值越大，优先级越高，BACKUP 不能大于MASTER
- advert_int 1 ######服务器之间的存活检查时间
- authentication {
- auth_type PASS ######认证类型
- auth_pass ufsoft ######认证密码，一组lvs 服务器的认证密码必须一致
- }
- track_script { ######执行监控mysql进程的脚本
- check_mysql
- }
- virtual_ipaddress { ######虚拟IP地址
- 192.168.1.60
- }
- }
这里state不配置MASTER，且优先级一样，是期望在MASTER1宕机后再恢复时，不主动将MASTER状态抢过来，避免MySQL服务的波动。
由于不存在使用lvs进行负载均衡，不需要配置虚拟服务器virtual server，下同。
4 vi /etc/sysconfig/iptables
#注意，在两台机器上都要修改。
添加：
-A INPUT -d 192.168.1.60/32 -j ACCEPT
-A INPUT -d 224.0.0.18 -j ACCEPT #添加VRRP通讯支持
注意：第一行中的192.168.1.60需要改成你自己的vip。
service iptables restart
5 启动keepalived
在master1、master2上分别启动：
service keepalived start
分别执行ip addr命令，可以在其中一台机器上看到虚拟IP.如：
[root@slave1 keepalived]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_faststate UP qlen 1000
link/ether 08:00:27:04:05:16 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.22/24 brd 192.168.1.255 scope global eth0
inet 192.168.1.60/32 scope global eth0
inet6 fe80::a00:27ff:fe04:516/64 scope link tentativedadfailed
valid_lft forever preferred_lft forever
说明虚拟vip连在了master1这台机器上。
如果自动只连接到了master2,关闭master2的keepalived，再启动，自动就连接到master1了。
现在都可以ping通虚拟ip了。
6 测试
停止master1服务器keepalived，检查VIP是否切换到master2服务器（用ip addr命令验证即可）；
三 测试高可用环境是否配置成功
3.1 建允许远程访问的用户
在master1,master2创建允许远程访问的用户：
grant select,update,delete,insert on *.* to 'dandan' identified by 'dandan';
3.2 访问虚拟IP
用一台同网段的机器访问通过vip访问数据库：
mysql -u dandan-pdandan -h 192.168.1.60 --port 3307
停止master1服务器的mysql，VIP切换到了master2服务器。
在master2上查看：
- mysql> showprocesslist;
- +----+-------------+--------------------+------+---------+------+-----------------------------------------------------------------------------+------------------+
- | Id | User | Host | db | Command | Time | State | Info |
- +----+-------------+--------------------+------+---------+------+-----------------------------------------------------------------------------+------------------+
- | 3 | root | localhost | dba | Query | 0 | init | show processlist |
- | 14 | systemuser | | NULL |Connect | 247 | Reconnecting after afailed master event read | NULL |
- | 15 | systemuser | | NULL |Connect | 207 | Slave has read all relaylog; waiting for the slave I/O thread to update it | NULL |
- | 90 |dandan | 192.168.1.60:39995 |dba | Sleep | 8| | NULL |
- +----+-------------+--------------------+------+---------+------+-----------------------------------------------------------------------------+------------------+
看到了dandan的连接信息。
