在centos下keepalive+nginx(proxy)+nginx(web)搭建

前言：

　　本文是在docker上安装四台centos下做测试，两台nginx服务器做负载，两台nginx服务器做后台应用服务器，keepalived安装在nginx负载上做主从切换。（nginx负载服务器的高可用。方式一：两台服务器（始终只有一台在用，另外一台处于待命状态；方式二：两台都在用，但是要绑定两个公网IP），个人学习了方式一并实践了一下。

　　最终实现：nginx-proxy-server1下的nginx关闭了，自动切换到nginx-proxy-server2上做web服务器的负载服务器使用

服务器	IP
nginx-web5	172.17.0.4
nginx-web6	172.17.0.5
nginx-proxy-server1	172.17.0.2
nginx-proxy-server2	172.17.0.3
虚拟IP(漂移IP)	172.17.0.18

1：NGINX的安装(分别在nginx-web5,nginx-web6,nginx-proxy-server1,nginx-proxy-server2)下安装nginx

yum update #更新一下系统补丁
yum install -y gcc gcc-c++ automake make libpcre3-dev libssl-dev openssl libnl libnl-3 libnfnetlink-devel openssl-devel   
cd /data/software
wget ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-8.40.tar.gz
wget http://zlib.net/zlib-1.2.11.tar.gz
wget http://nginx.org/download/nginx-1.13.0.tar.gz
tar -zxvf zlib-1.2.11.tar.gz
tar -zxvf pcre-8.40.tar.gz
tar -zxvf nginx-1.13.0.tar.gz 
cd nginx-1.13.0
mkdir -p /data/service/nginx
./configure --prefix=/data/service/nginx/ --with-pcre=/data/software/pcre-8.40 --with-zlib=/data/software/zlib-1.2.11 --with-openssl=/usr/lib64/openssl 
make && make install

启动nginx /data/service/nginx/sbin/nginx

2：NGINX(WEB配置）

vi /data/service/nginx/html/index  (nginx-web5)

<html>
<head>
<title>Welcome to nginx!</title>
</head>
<body>
<h1> 172.17.0.4 ( nginx-web5 ) </h1>
</body>
</html>

vi /data/service/nginx/html/index  (nginx-web6)

<html>
<head>
<title>Welcome to nginx!</title>
</head>
<body>
<h1> 172.17.0.5 ( nginx-web6 ) </h1>
</body>
</html>

3：NGINX(proxy配置）

vi  /data/service/nginx/conf/nginx.conf (nginx-proxy-server1:172.17.0.2) 
在http{

    upstream testHA {
         server 172.17.0.4;
         server 172.17.0.5;
    }

   server {
         location / {
             proxy_pass http://testHA;          
        }      
   }

}

4：keepalived安装

 yum -y install libnl libnl-devel
yum install keepalived

5：keepalived配置

master(主）： vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {
  # notification_email {
  #      dxh20012012001@sina.com
  # }
  # notification_email_from dengxiaohui2001@163.com
  # smtp_server smtp.163.com
  # smtp_connect_timeout 30
   router_id LVS_DEVEL
  # vrrp_skip_check_adv_addr
  # vrrp_strict
  # vrrp_garp_interval 0
  # vrrp_gna_interval 0
}

vrrp_script chk_nginx {
    script "/data/service/keepalived/scripts/check_nginx.sh"
    #script "[[ -e /etc/keepalived/down ]] && exit 1 || exit 0"
    interval 1
    weight -2
    rise 3
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 101
    advert_int 1
    mcast_src_ip  172.10.0.2
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.17.0.18/32
    }

   track_script {
        chk_nginx
   }

}

slave:

脚本：/data/service/keepalived/scripts/check_nginx.sh

#!/bin/bash
nginxPidNum=`ps -C nginx --no-header |wc -l`
keepalivedPidNum=`ps -C keepalived --no-header |wc -l`
if [ $nginxPidNum -eq 0 ]; then
    if [ $keepalivedPidNum -ne 0 ]; then
        killall keepalived
    fi
elif [ $keepalivedPidNum -eq 0 ]; then
    /usr/sbin/keepalived
fi

　　开启 nginx-proxy-server1和nginx-proxy-server2上的nginx和keepalived

/data/service/nginx/sbin/nginx

/usr/sbin/keepalived

　　查看虚拟IP（172.17.0.18）是否绑定在nginx-proxy-server1上面

　　ip addr show

6：keepalived测试

　　在(nginx-proxy-server1)关闭掉nginx看ip是否漂移到nginx-proxy-server2上(ip addr show)

或者LINUX下直接访问：curl http://172.17.0.18 还是继续可以访问到web5,web6下的页面

参考文档：

http://seanlook.com/2015/05/18/nginx-keepalived-ha/

https://blog.linuxeye.cn/447.html