nginx+keepalived高可用实战

1、整体架构图如下

2、环境准备

今天所配置的是keepalived+nginx 的负载均衡

下载keepalived软件

[root@LB01 tools]# wget http://www.keepalived.org/software/keepalived-1.1.17.tar.gz

注意安装前检查内核的link文件

root@LB02 tools]# ll /usr/src/

total 8

drwxr-xr-x. 2 root root 4096 Sep 23  2011 debug

drwxr-xr-x. 3 root root 4096 Oct 19 02:03 kernels

lrwxrwxrwx. 1 root root 43 Oct 19 02:05 linux -> /usr/src/kernels/2.6.32-642.6.1.el6.x86_64/

安装keepalived之前，安装几个依赖包

yum install openssl-devel -y

yum install popt* -y

然后进行编译安装keepalived,前面介绍了安装过程，这里就不演示了

./configure得出下面的结果

Keepalived configuration

------------------------

Keepalived version    : 1.1.17

Compiler         : gcc

Compiler        : -g -O2

Extra Lib      : -lpopt -lssl -lcrypto

Use IPVS Framework   : Yes

IPVS sync daemon support : Yes

Use VRRP Framework    : Yes

Use LinkWatch      : No

Use Debug flags     : No

注意./configure之后的结果，没有错误就可以了

make && make install

之后规范配置、启动文件路径

/bin/cp /usr/local/etc/rc.d/init.d/keepalived /etc/init.d/

/bin/cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/

mkdir /etc/keepalived -p

/bin/cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/

/bin/cp /usr/local/sbin/keepalived /usr/sbin/

/etc/init.d/keepalived start

注：nginx负载均衡相关配置请参考前面的文章

LNMP架构应用实战—Nginx反向代理负载均衡配置

3、实战配置keepalived

[root@LB01 keepalived]# vi keepalived.conf

! Configuration File for keepalived

global_defs {

notification_email {

abc@qq.com

}

notification_email_from Alexandre.Cassen@firewall.loc

smtp_server 1.1.1.1

smtp_connect_timeout 30

router_id LVS_3

}

vrrp_instance VI_1 {

state MASTER

interface eth0

virtual_router_id 19

priority 150

advert_int 1

authentication {

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {

192.168.1.254/24

}

}

[root@LB02 keepalived]# vi keepalived.conf

! Configuration File for keepalived

global_defs {

notification_email {

abc@qq.com

}

notification_email_from Alexandre.Cassen@firewall.loc

smtp_server 1.1.1.1

smtp_connect_timeout 30

router_id LVS_6

}

vrrp_instance VI_1 {

state BACKUP

interface eth0

virtual_router_id 19

priority 100

advert_int 1

authentication {

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {

192.168.1.254/24

}

}

[root@LB01 keepalived]# /etc/init.d/keepalived start

Starting keepalived:    [  OK  ]

[root@LB02 keepalived]# /etc/init.d/keepalived start

Starting keepalived    [  OK  ]

[root@LB01 keepalived]# ip add|grep 192.168.1.254

inet 192.168.1.254/24 scope global secondary eth0

[root@LB02 keepalived]# ip add|grep 192.168.1.254

测试访问

表明可以正常切换

现在我们模拟keepalived主宕机，再测试

[root@LB01 conf]# /etc/init.d/keepalived stop

Stopping keepalived:   [  OK  ]

[root@LB02 ~]# ip add|grep 254

inet 192.168.1.254/24 scope global secondary eth0

4、反向代理服务故障自动切换

如果实际生产环境中当keeplived主的服务器nginx服务宕机，但是主又有VIP，这时就出现无法访问的现象，因此可以做如下的配置，使得这种情况可自已切换

vi check_nginx.sh

#!/bin/sh

white true

do

PNUM=`ps -ef|grep nginx|wc -l`

#这里也可使用nmap 192.168.1.3 -p 80|grep open|wc -l来判断个数

if [ $PNUM -lt 3 ];then

/etc/init.d/keepalived stop >/dec/null 2>&1

kill -9 keealived >/dec/null 2>&1

kill -9 keealived >/dec/null 2>&1

fi

sleep 5

done

sh check_nginx.sh &

启动个守护进程进行检查（或者加入定时任务定时执行检查），如果nginx服务出现故障，就立马停掉keepalived的服务，让它自动切换到备节点上去，这样就实现了自动切换的工作