使用KeepAlived实现HAProxy高可用

在以前的文章中我们实现了使用HAProxy来转发读请求到后端多台mysql从库上，但是对于HAProxy的高可用(HA)需

求没有配置，本文在以前的基础再增加一个HAProxy的备份机器.这样当主服务器的HAProxy挂掉后，备份机器能够迅

速的进行自动接管.我们通过KeepAlived来实现这样的需求

主HAProxy: 192.168.10.192

备HAProxy: 192.168.10.85

VIP:192.168.10.158

整个项目的拓扑结构如下.

vip

|

--主haproxy--  --备haproxy--

|     \

|      \

--mysql--  --mysql--

--在主，备HAProxy上安装keepalived软件

[root@cscscslocalhost 1109]# tar -xvf keepalived-1.2.1.tar.gz

[root@cscscslocalhost keepalived-1.2.1]# ./configure --prefix=/usr/local/keepalived

checking for gcc... gcc

[root@cscscslocalhost keepalived-1.2.1]# make

[root@cscscslocalhost keepalived-1.2.1]# make install

--在主，备HAProxy上把KeepAlived的安装目录下的sbin目录加到.bash_profile文件中，然后source生效

PATH=$PATH:$HOME/bin:/usr/local/haproxy/sbin:/sbin:/bin:/usr/local/keepalived/sbin

--在主，备HAProxy上查看keepalived,确保成功安装.

[root@cscscslocalhost sbin]# keepalived -v

Keepalived v1.2.1 (11/12,2014)

--在主，备HAProxy上修改KeepAlived的配置文件

主HAProxy的配置

[root@cscscslocalhost keepalived]# vi /usr/local/keepalived/etc/keepalived/keepalived.conf

global_defs {

notification_email {

}

#notification_email_from

#smtp_server 192.168.200.1

#smtp_connect_timeout 30

router_id LVS_DEVEL

}

vrrp_script chk_haproxy

{

script "/usr/local/keepalived/chk_haproxy.sh"

interval 1

weight 2

}

vrrp_instance VI_1 {

state MASTER

interface eth0

virtual_router_id 51

priority 101

advert_int 1

mcast_src_ip 192.168.10.192

authentication {

auth_type PASS

auth_pass 111111

}

track_script {

chk_haproxy

}

virtual_ipaddress {

192.168.10.158

}

}

备用HAProxy服务器的配置

global_defs {

notification_email {

}

#notification_email_from

#smtp_server 192.168.200.1

#smtp_connect_timeout 30

router_id LVS_DEVEL

}

vrrp_script chk_haproxy

{

script "/usr/local/keepalived/chk_haproxy.sh"

interval 1

weight 2

}

vrrp_instance VI_1 {

state BACKUP

interface eth0

virtual_router_id 51

priority 100

advert_int 1

mcast_src_ip 192.168.10.85

authentication {

auth_type PASS

auth_pass 111111

}

track_script {

chk_haproxy

}

virtual_ipaddress {

192.168.10.158

}

}

--在主，备HAProxy上编写脚本文件，这个脚本的目的是检查HAProxy存活性，如果HAProxy

死掉了，那么KeepAlived也会被杀死，这样保证备HAProxy能确正常的接管

[root@cscscslocalhost ~]# vi /usr/local/keepalived/chk_haproxy.sh

#!/bin/bash

status=$(ps aux|grep haproxy | grep -v grep | grep -v bash | wc -l)

if [ ${status} = "0" ]; then

/bin/kill -9 `/sbin/pidof keepalived`

fi

--在主，备HAProxy上修改脚本执行权限

[root@cscscslocalhost ~]# chmod 755 /usr/local/keepalived/chk_haproxy.sh

--在主HAProxy上启动KeepAlived,通过/var/log/messages,可以看出已经功启动,并进入master状态

[root@cscscslocalhost keepalived]# keepalived -f /usr/local/keepalived/etc/keepalived/keepalived.conf

[root@cscscslocalhost ~]# tail -f /var/log/messages

Nov 12 14:28:15 cscscslocalhost Keepalived: Starting Keepalived v1.2.1 (11/12,2014)

Nov 12 14:28:15 cscscslocalhost Keepalived_vrrp: Registering Kernel netlink reflector

Nov 12 14:28:15 cscscslocalhost Keepalived_vrrp: Registering Kernel netlink command channel

Nov 12 14:28:15 cscscslocalhost Keepalived_vrrp: Registering gratutious ARP shared channel

Nov 12 14:28:15 cscscslocalhost Keepalived_vrrp: Opening file '/usr/local/keepalived/etc/keepalived/keepalived.conf'.

Nov 12 14:28:15 cscscslocalhost Keepalived_vrrp: Configuration is using : 64914 Bytes

Nov 12 14:28:15 cscscslocalhost Keepalived_vrrp: Using LinkWatch kernel netlink reflector...

Nov 12 14:28:15 cscscslocalhost Keepalived: Starting VRRP child process, pid=17731

Nov 12 14:28:15 cscscslocalhost Keepalived_vrrp: VRRP_Script(chk_haproxy) succeeded

Nov 12 14:28:16 cscscslocalhost Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATE

Nov 12 14:28:17 cscscslocalhost Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE

[root@cscscslocalhost keepalived]# ip a

1: lo: mtu 16436 qdisc noqueue

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

2: eth0: mtu 1500 qdisc pfifo_fast qlen 1000

link/ether 1c:6f:65:d9:4a:6f brd ff:ff:ff:ff:ff:ff

inet 192.168.10.192/24 brd 192.168.10.255 scope global eth0

inet 192.168.10.158/32 scope global eth0

--测试通过VIP来连接mysql

[root@localhost ~]# mysql -u root -p123456 --host=192.168.10.158 --port=23306

Warning: Using a password on the command line interface can be insecure.

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 50484

Server version: 5.6.14-rel62.0 Percona Server with XtraDB (GPL), Release rel62.0, Revision 483

Copyright (c) 2009-2013 Percona LLC and/or its affiliates

Copyright (c) 2000, 2013, 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> show databases;

+--------------------+

| Database           |

+--------------------+

| information_schema |

| db1                |

| mysql              |

| performance_schema |

| login_sso         |

| zabbix             |

+--------------------+

6 rows in set (0.00 sec)

连接成功.

手动在主HAProxy上杀死haproxy,模拟haproxy故障,这样备份HAProxy会进行接管.

[root@cscscslocalhost keepalived]# ps  -eaf | grep 4852

nobody    4852     1  0 15:13 ?        00:00:00 haproxy -f /etc/haproxy.cfg

root      5019 12171  0 15:13 pts/0    00:00:00 grep 4852

[root@cscscslocalhost keepalived]# kill -9 4852

--备份HAProxy的/var/log/messages日志,可以看出备份HAProxy已经接管了VIP

Nov 12 14:27:56 db135 Keepalived_vrrp: VRRP_Instance(VI_1) Received higher prio advert

Nov 12 14:27:56 db135 Keepalived_vrrp: VRRP_Instance(VI_1) Entering BACKUP STATE

Nov 12 14:28:41 db135 Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATE

Nov 12 14:28:42 db135 Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE

Nov 12 14:28:48 localhost.localdomain haproxy[12523]: Connect from 192.168.10.145:54535 to 192.168.10.158:23306 (mysql_proxy/TCP)

--重新show databases,发现已经重连了，整个过程在2-3秒的样子.

mysql> show databases;

No connection. Trying to reconnect...

Connection id:    50815

Current database: *** NONE ***

+--------------------+

| Database           |

+--------------------+

| information_schema |

| db1                |

| mysql              |

| performance_schema |

| login_sso         |

| zabbix             |

+--------------------+

6 rows in set (0.00 sec)