nginx+keepalived实现双机热备

陈银山

　　下载keeplived：



cd /usr/local/src
wget http://www.keepalived.org/software/keepalived-1.2.12.tar.gz
tar zxvf keepalived-1.2.12.tar.gz
cd keepalived-1.2.12

　　编译&安装



./configure  --prefix=/usr/local/keepalived
make
make install
　　配置



cp /usr/local/keepalived/etc/sysconfig/keepalived  /etc/sysconfig/keepalived
mkdir /etc/keepalived
ln -s /usr/local/keepalived/etc/keepalived/keepalived.conf  /etc/keepalived/
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
cp /usr/local/keepalived/etc/rc.d/init.d/keepalived  /etc/rc.d/init.d/
#添加执行权限
chmod +x /etc/rc.d/init.d/keepalived
#设置开机启动
chkconfig keepalived on
#启动
service keepalived start
#关闭
service keepalived stop
#重启
service keepalived restart
　　创建Nginx检测脚本



touch /usr/local/keepalived/check_nginx.sh


#!/bin/sh
if [ $(ps -C nginx --no-header | wc -l) -eq 0 ]; then
/etc/rc.d/init.d/nginx  start
fi
sleep 2
if [ $(ps -C nginx --no-header | wc -l) -eq 0 ]; then
/etc/rc.d/init.d/keepalived  stop
fi


# 增加运行权限
chmod +x /usr/local/keepalived/check_nginx.sh
# 备份主默认配置
cp /usr/local/keepalived/etc/keepalived/keepalived.conf  /usr/local/keepalived/etc/keepalived/keepalived.conf-bak
　　编辑主配置



vi /usr/local/keepalived/etc/keepalived/keepalived.conf


! Configuration File for keepalived
global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id cbpt01
}
vrrp_script chk_http_port {
script "/usr/local/keepalived/check_nginx.sh"   #在这里添加脚本链接
interval 3                                      #脚本执行间隔
weight 2                                        #脚本结果导致的优先级变更
}
vrrp_instance VI_NODE {
state MASTER
interface eth0
virtual_router_id 100
priority 200
advert_int 5
authentication {
auth_type PASS
auth_pass 123456
}
track_script {
chk_http_port #添加脚本执行
}
virtual_ipaddress {
10.3.20.51
}
}


# 备份从默认配置
cp /usr/local/keepalived/etc/keepalived/keepalived.conf  /usr/local/keepalived/etc/keepalived/keepalived.conf-bak
# 编辑从配置
vi /usr/local/keepalived/etc/keepalived/keepalived.conf


! Configuration File for keepalived
global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id cbpt02
}
vrrp_instance VI_NODE {
state BACKUP                 #与主服务器对应
interface eth0               #从服务器的通信网卡
virtual_router_id 100        #路由标识，和主服务器相同
priority 90                  #优先级，小于主服务器即可
advert_int 5                 #这里是接受通知间隔，与主服务器要设置相同  
authentication {
auth_type PASS
auth_pass 123456         #验证密码，与主服务器相同
}  
virtual_ipaddress {
10.3.20.51               #虚拟IP，也要和主服务器相同
}
}
　　配置完成后就可以运行看下效果了,分别在主从服务器上启动nginx和keepalived
　　



service keepalived start
　　启动之后通过 ip a 命令查看主服务器的网络信息，可以看到在eth0网卡下生成了10.3.20.51这个虚拟ip，并可通过这个ip访问到nginx
然后我们关闭nginx的进程（如果配置了一次尝试重启那要注意下），然后我们可以通过ps -e查看keepalived进程是否关闭，正常情况下查看网络信息中，可以看到eth0网卡下的虚拟ip已经解除，然后在从服务器的网络信息中可以看到从服务器的eth0网卡绑定了虚拟ip，通过这个ip就访问到了从服务器的nginx去了，这是我们重新启动主服务器的nginx和keepalieved，我们可以发现虚拟ip就绑回到了主服务器。
这样就实现了基本双击主从热备功能了。