Nginx高性能、稳定性成为IT人士青睐的http和反向代理服务器。今天我们来一起来温习一下Nginx+Keepalived高可用配置，鉴于互联网类似的优秀文章很多，这里仅供参考和交流。
一、实验环境：
系统环境：CentOS 6.0 x86_64
Nginx版本：nginx v1.2.4
Keepalived版本：keepalived v1.2.1
Nginx-1：192.9.117.160 （Master）
Nginx-2：192.9.117.161 （Backup）
二、Nginx安装配置：
分别在两台服务器安装Nginx、keepalived，如下：
yum install -y pcre-devel 安装perl 兼容的正规表达式库
tar -xzf nginx-1.2.4.tar.gz && cd nginx-1.2.4 ; sed -i -e 's/1.2.2//g' -e 's/nginx//TDTWS/g' -e 's/"NGINX"/"TDTWS"/g' src/core/nginx.h &&./configure --prefix=/usr/local/nginx --user=www --group=www --with-http_stub_status_module --with-http_ssl_module
三、Keepalived安装配置：
tar -xzvf keepalived-1.2.1.tar.gz &&cd keepalived-1.2.1 && ./configure && make && make install
if
[ $? -eq 0 ];then
echo "Install keepalived success,please waiting configure keepalived ..............."
else
echo "Install keepalived failed ,please check install version !"
exit 0
fi
DIR=/usr/local/ ;cp $DIR/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/ ; cp $DIR/etc/sysconfig/keepalived /etc/sysconfig/ ; mkdir -p /etc/keepalived ; cp $DIR/sbin/keepalived /usr/sbin/
Nginx、Keepalived软件安装完毕，接下来进行详细配置。
四、配置Keepalived：
两台服务器端keepalived.conf内容都为如下，都设置为backup，不抢占，注意修改优先级不同：
! Configuration File for keepalived
global_defs {
notification_email {
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_nginx {
script "/data/sh/check_nginx.sh"
interval 2
weight 2
}
# VIP1
vrrp_instance VI_1 {
state BACKUP
interface eth0
lvs_sync_daemon_inteface eth0
virtual_router_id 151
priority 100
advert_int 5
nopreempt
authentication {
auth_typePASS
auth_pass 1111
}
virtual_ipaddress {
192.9.117.162
}
track_script {
chk_nginx
}
}
如上配置，我们需要自己建立check_nginx脚本，以方便检查本地Nginx是否存活更好的切换。Check_nginx.sh脚本内容如下：
#!/bin/bash
#auto check nginx process
#2012-10-16 wugk
killall -0 nginx
if
[[ $? -ne 0 ]];then
/etc/init.d/keepalived stop
fi
五、Nginx 配置：
在两台Nginx服务器分别新建index.html测试页面，然后启动Nginx服务测试。
访问VIP http://192.9.117.162 如下：
Down掉192.9.117.160的Nginx服务，分别查看keepalived后台日志和ping VIP日志如下：
Oct 16 16:47:48 localhost Keepalived: Stopping Keepalived v1.2.1 (10/16,2012)
Oct 16 16:47:49 localhost Keepalived_vrrp: Terminating VRRP child process on signal
至此，Nginx+Keepalived高可用WEB架构搭建成功！目前此套系统已经在线上使用，后期会观察使用情况并分享给大家，欢迎多交流！