一、keepalived 介绍

浅析keepalived vip漂移原理与VRRP协议

二、实验环境
mysql master : 192.168.111.52
mysql slave   : 192.168.111.53
keepalived vip : 192.168.111.60

三、搭建过程
1. mysql双主的构建
      ① 互相 change master 即可，此处省略该过程，着重讲下keepalived

2. keepalived相关
      ①  yum -y install keepalived 安装keepalived
        ② root@192.168.111.52:~# keepalived -v
            Keepalived v1.2.7 (02/21,2013)

③ 编辑 /etc/keepalived/keepalived.conf

点击(此处)折叠或打开

root@192.168.111.52:keepalived# cat keepalived.conf
! Configuration File for keepalived
global_defs {##全局配置
notification_email {
horand_gc@163.com #####邮件接收者
}
notification_email_from dba@163.com #####邮件发送者
smtp_server smtp.163.com #####SMTP服务器
smtp_connect_timeout 30
router_id haMySQL #####routerID 同一组keepalived设置为相同
}
vrrp_script chk_mysql {##健康检测相关配置
script "/etc/keepalived/chk_mysql.sh" #####设置脚本或者直命令返回 0 则表示成功 >0 则表示失败，详情可以后面的脚本内容
interval 1 #####检测间隔
weight 2 #####检测返回失败之后优先级会减少 2 (如果 master优先级100 ， slave 优先级 99 ,master检测失败则优先级为100-2 < 99 ，则slave会提升为主)
}
vrrp_instance VI_1 {
state MASTER ##### 设为master
interface eth1 ##### 网卡设定
virtual_router_id 51 ##### 针对该 instance的虚拟id , 同一组 instance设置相同
priority 100 ##### 优先级设定
advert_int 1 ##### 检测时间间隔
authentication {
auth_type PASS ##### 同一组instance之间的认证方式为 PASS ,pass 为7777 ，必须相同(防止有用户恶意伪造 vrrp)
auth_pass 7777
}
virtual_ipaddress {
192.168.111.60 ##### 设置虚拟ip ,可以设置多个
}
track_script {
chk_mysql ##### 表示该instance 使用chk_mysql进行相关检测
}
##### 以下配置在该实例转换为 master,slave，或者出错的时候执行的脚本(可以设置邮件通知，或者处理一些其他问题)
# notify_master "/etc/keepalived/change_master.sh"
# notify_slave "/etc/keepalived/change_slave.sh"
# notify_fault "/etc/keepalived/change_fault.sh"
}
root@192.168.111.53:keepalived# cat keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
horand_gc@163.com
}
notification_email_from dba@163.com
smtp_server smtp.163.com
smtp_connect_timeout 30
router_id haMySQL
}
vrrp_script chk_mysql {
script "/etc/keepalived/chk_mysql.sh"
interval 1
weight 2
}
vrrp_instance VI_1 {
state BACKUP ##### 该主机作为备机 BACKUP
interface eth1
virtual_router_id 51
priority 99 ##### 优先级设置小于 master
advert_int 1
authentication {
auth_type PASS
auth_pass 7777
}
virtual_ipaddress {
192.168.111.60
}
track_script {
chk_mysql
}
}
root@192.168.111.52:keepalived# cat chk_mysql.sh
#!/bin/bash
num=`ps -ef |grep mysqld | grep -v grep | wc -l` ##### 查看mysqld进程数量，正常情况有一个root起的mysqld_safe守护进程，还有一个属于mysql用户的mysqld进程
[[ $num -eq 2 ]] && exit 0 || exit 1

3. 故障模拟
① 启动 keepalived

点击(此处)折叠或打开

root@192.168.111.52:keepalived# tail /var/log/messages
Apr 29 13:45:24 localhost Keepalived_healthcheckers[24184]: Registering Kernel netlink command channel
Apr 29 13:45:24 localhost Keepalived_healthcheckers[24184]: Opening file '/etc/keepalived/keepalived.conf'.
Apr 29 13:45:24 localhost Keepalived_healthcheckers[24184]: Configuration is using : 7417 Bytes
Apr 29 13:45:24 localhost Keepalived_vrrp[24185]: Opening file '/etc/keepalived/keepalived.conf'.
Apr 29 13:45:24 localhost Keepalived_vrrp[24185]: Configuration is using : 65552 Bytes
Apr 29 13:45:24 localhost Keepalived_vrrp[24185]: Using LinkWatch kernel netlink reflector...
Apr 29 13:45:24 localhost Keepalived_healthcheckers[24184]: Using LinkWatch kernel netlink reflector...
Apr 29 13:45:25 localhost Keepalived_vrrp[24185]: VRRP_Script(chk_mysql) succeeded
Apr 29 13:45:25 localhost Keepalived_vrrp[24185]: VRRP_Instance(VI_1) Transition to MASTER STATE
Apr 29 13:45:26 localhost Keepalived_vrrp[24185]: VRRP_Instance(VI_1) Entering MASTER STATE
root@192.168.111.53:keepalived# tailf /var/log/messages
Apr 29 13:49:27 localhost Keepalived_healthcheckers[32569]: Registering Kernel netlink reflector
Apr 29 13:49:27 localhost Keepalived_healthcheckers[32569]: Registering Kernel netlink command channel
Apr 29 13:49:27 localhost Keepalived_vrrp[32570]: Opening file '/etc/keepalived/keepalived.conf'.
Apr 29 13:49:27 localhost Keepalived_vrrp[32570]: Configuration is using : 65550 Bytes
Apr 29 13:49:27 localhost Keepalived_vrrp[32570]: Using LinkWatch kernel netlink reflector...
Apr 29 13:49:27 localhost Keepalived_healthcheckers[32569]: Opening file '/etc/keepalived/keepalived.conf'.
Apr 29 13:49:27 localhost Keepalived_healthcheckers[32569]: Configuration is using : 7415 Bytes
Apr 29 13:49:27 localhost Keepalived_vrrp[32570]: VRRP_Instance(VI_1) Entering BACKUP STATE
Apr 29 13:49:27 localhost Keepalived_healthcheckers[32569]: Using LinkWatch kernel netlink reflector...
Apr 29 13:49:27 localhost Keepalived_vrrp[32570]: VRRP_Script(chk_mysql) succeeded

ip a 可以查看到 vip 192.168.111.60 在 192.168.111.52(master)上

② 关闭 111.52上面的mysql

点击(此处)折叠或打开

root@192.168.111.52:keepalived# mysqladmin shutdown
root@192.168.111.52:keepalived# tailf /var/log/messages
Apr 29 14:19:30 localhost Keepalived_vrrp[24862]: VRRP_Script(chk_mysql) failed
Apr 29 14:19:32 localhost Keepalived_vrrp[24862]: VRRP_Instance(VI_1) Received higher prio advert
Apr 29 14:19:32 localhost Keepalived_vrrp[24862]: VRRP_Instance(VI_1) Entering BACKUP STATE
root@192.168.111.53:keepalived# tailf /var/log/messages
Apr 29 14:19:55 localhost Keepalived_vrrp[566]: VRRP_Instance(VI_1) forcing a new MASTER election
Apr 29 14:19:56 localhost Keepalived_vrrp[566]: VRRP_Instance(VI_1) Transition to MASTER STATE
Apr 29 14:19:57 localhost Keepalived_vrrp[566]: VRRP_Instance(VI_1) Entering MASTER STATE

ip a 可以查看到 vip 192.168.111.60 在 192.168.111.53(master)上

③ 启动111.52上面的mysql

点击(此处)折叠或打开

root@192.168.111.52:keepalived# mysqld_safe & ; tailf /var/log/messages
Apr 29 14:24:21 localhost Keepalived_vrrp[24862]: VRRP_Script(chk_mysql) succeeded
Apr 29 14:24:22 localhost Keepalived_vrrp[24862]: VRRP_Instance(VI_1) forcing a new MASTER election
Apr 29 14:24:23 localhost Keepalived_vrrp[24862]: VRRP_Instance(VI_1) Transition to MASTER STATE
Apr 29 14:24:24 localhost Keepalived_vrrp[24862]: VRRP_Instance(VI_1) Entering MASTER STATE
root@192.168.111.53:keepalived# tailf /var/log/messages
Apr 29 14:24:45 localhost Keepalived_vrrp[566]: VRRP_Instance(VI_1) Received higher prio advert
Apr 29 14:24:45 localhost Keepalived_vrrp[566]: VRRP_Instance(VI_1) Entering BACKUP STATE

ip a 可以查看到 vip 192.168.111.60 在 192.168.111.52(master)上，也就是说111.52会持续通过track_script的脚本检查，若成功的话会恢复原来的优先级100 ，便把vip抢过来了(若不希望优先级高的直接上来直接抢占vip的话需要再instance 里面配置 nopreempt ,backup无需设置)

四、虚拟server
以上是实验是通过 vrrp_script以及trace_script 实现优先级变换来实现故障转移的，现在看下通过虚拟server怎么实现mysql的高可用
① 配置

点击(此处)折叠或打开

root@192.168.111.52:keepalived# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
tab@taomee.com
}
notification_email_from dba@taomee.com
smtp_server smtp.shidc.taomee.com
smtp_connect_timeout 30
router_id haMySQL
}
vrrp_script chk_mysql {
script "/etc/keepalived/chk_mysql.sh"
interval 1
weight 2
}
vrrp_instance VI_1 {
state MASTER
interface eth1
virtual_router_id 51
priority 100
nopreempt
advert_int 1
authentication {
auth_type PASS
auth_pass 7777
}
virtual_ipaddress {
192.168.111.60
}
# track_script {
# chk_mysql
# }
}
virtual_server 192.168.111.60 3306 {
delay_loop 6
persistence_timeout 300
protocol TCP
real_server 192.168.111.52 3306 {
weight 1
notify_down /etc/keepalived/kill_self.sh
TCP_CHECK {
tcp_port 3306
connect_timeout 3
}
}
}
root@192.168.111.53:keepalived# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
tab@taomee.com
}
notification_email_from dba@taomee.com
smtp_server smtp.shidc.taomee.com
smtp_connect_timeout 30
router_id haMySQL
}
vrrp_script chk_mysql {
script "/etc/keepalived/chk_mysql.sh"
interval 1
weight 2
}
vrrp_instance VI_1 {
state BACKUP
interface eth1
virtual_router_id 51
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 7777
}
virtual_ipaddress {
192.168.111.60
}
# track_script { #########这里先注释掉通过追踪脚本的检查
# chk_mysql
# }
}
virtual_server 192.168.111.60 3306 {
delay_loop 6
persistence_timeout 300
protocol TCP
real_server 192.168.111.53 3306 {### 真实服务
weight 1 #### 权重，用来多真实服务均衡使用
notify_down /etc/keepalived/kill_self.sh ####在检查该服务不可用时执行该脚本(用来杀死 keepalived 实现 vip 飘逸)
TCP_CHECK {
tcp_port 3306 #### 检查端口继承 real_server 192.168.111.53 3306 {### 真实服务
connect_timeout 3 #### tcp超时时间
}
}
}
root@192.168.111.53:keepalived# cat /etc/keepalived/kill_self.sh
#!/bin/bash
killall keepalived

②启动keepalived

点击(此处)折叠或打开

root@192.168.111.52:keepalived# keepalived
root@192.168.111.52:keepalived# tailf /var/log/messages
Apr 29 14:48:22 localhost Keepalived_vrrp[20482]: Opening file '/etc/keepalived/keepalived.conf'.
Apr 29 14:48:22 localhost Keepalived_vrrp[20482]: Configuration is using : 64590 Bytes
Apr 29 14:48:22 localhost Keepalived_vrrp[20482]: Using LinkWatch kernel netlink reflector...
Apr 29 14:48:22 localhost Keepalived_healthcheckers[20481]: IPVS: Scheduler not found
Apr 29 14:48:22 localhost kernel: IPVS: Scheduler module ip_vs_ not found
Apr 29 14:48:22 localhost Keepalived_healthcheckers[20481]: IPVS: Service not defined
Apr 29 14:48:22 localhost Keepalived_healthcheckers[20481]: Using LinkWatch kernel netlink reflector...
Apr 29 14:48:22 localhost Keepalived_healthcheckers[20481]: Activating healthchecker for service [192.168.111.52]:3306
Apr 29 14:48:23 localhost Keepalived_vrrp[20482]: VRRP_Instance(VI_1) Transition to MASTER STATE
Apr 29 14:48:24 localhost Keepalived_vrrp[20482]: VRRP_Instance(VI_1) Entering MASTER STATE
root@192.168.111.53:keepalived# keepalived
root@192.168.111.53:keepalived# tailf /var/log/messages
Apr 29 14:48:51 localhost Keepalived_healthcheckers[25092]: Configuration is using : 11673 Bytes
Apr 29 14:48:51 localhost Keepalived_vrrp[25093]: Opening file '/etc/keepalived/keepalived.conf'.
Apr 29 14:48:51 localhost Keepalived_vrrp[25093]: Configuration is using : 64568 Bytes
Apr 29 14:48:51 localhost Keepalived_vrrp[25093]: Using LinkWatch kernel netlink reflector...
Apr 29 14:48:51 localhost Keepalived_vrrp[25093]: VRRP_Instance(VI_1) Entering BACKUP STATE
Apr 29 14:48:51 localhost kernel: IPVS: Scheduler module ip_vs_ not found
Apr 29 14:48:51 localhost Keepalived_healthcheckers[25092]: IPVS: Scheduler not found
Apr 29 14:48:51 localhost Keepalived_healthcheckers[25092]: IPVS: Service not defined
Apr 29 14:48:51 localhost Keepalived_healthcheckers[25092]: Using LinkWatch kernel netlink reflector...
Apr 29 14:48:51 localhost Keepalived_healthcheckers[25092]: Activating healthchecker for service [192.168.111.53]:3306

此时 ip a 命令可以查看虚拟ip 111.60 在111.52(master) 上

③关闭 111.52上的mysql

点击(此处)折叠或打开

root@192.168.111.52:keepalived# mysqladmin shutdown
2017-04-29T07:07:38.121123Z mysqld_safe mysqld from pid file /opt/mysql/mysqld.pid ended
[1]+ Done mysqld_safe
root@192.168.111.52:keepalived# tailf /var/log/messages
Apr 29 15:07:31 localhost Keepalived_healthcheckers[23405]: TCP connection to [192.168.111.52]:3306 failed !!!
Apr 29 15:07:31 localhost Keepalived_healthcheckers[23405]: Removing service [192.168.111.52]:3306 from VS [192.168.111.60]:3306
Apr 29 15:07:31 localhost Keepalived_healthcheckers[23405]: IPVS: Service not defined
Apr 29 15:07:31 localhost Keepalived_healthcheckers[23405]: Executing [/etc/keepalived/kill_self.sh] for service [192.168.111.52]:3306 in VS [192.168.111.60]:3306
Apr 29 15:07:31 localhost Keepalived_healthcheckers[23405]: Lost quorum 1-0=1 > 0 for VS [192.168.111.60]:3306
Apr 29 15:07:31 localhost Keepalived_healthcheckers[23405]: Remote SMTP server [0.0.0.0]:25 connected.
Apr 29 15:07:31 localhost Keepalived[23404]: Stopping Keepalived v1.2.7 (02/21,2013)
Apr 29 15:07:31 localhost Keepalived_healthcheckers[23405]: IPVS: No such service
Apr 29 15:07:31 localhost Keepalived_vrrp[23406]: VRRP_Instance(VI_1) sending 0 priority
root@192.168.111.53:keepalived# tailf /var/log/messages
Apr 29 15:07:32 localhost Keepalived_vrrp[26815]: VRRP_Instance(VI_1) Transition to MASTER STATE
Apr 29 15:07:33 localhost Keepalived_vrrp[26815]: VRRP_Instance(VI_1) Entering MASTER STATE

此时 ip a 命令可以看到虚拟ip 111.60在111.53(新master)上

以上

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