Nginx+keepalived高可用配置实战(内附彩蛋)

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