企业级Nginx+Keepalived集群实战（双主架构）

        随着Nginx在国内的发展潮流，越来越多的互联网公司都在使用Nginx，Nginx高性能、稳定性成为IT人士青睐的HTTP和反向代理服务器。Nginx负载均衡一般位于整个网站架构的最前端或者中间层，如果为最前端时单台Nginx会存在单点故障，也就是一台Nginx宕机，会影响用户对整个网站的访问。所以需要加入Nginx备份服务器，Nginx主服务器与备份服务器之间形成高可用，一旦发现Nginx主宕机，能快速将网站恢复至备份主机。Nginx+keepalived网络架构如图23-1所示：

                    

Nginx+keepalived高性能WEB网络架构实战配置如下步骤：

1、环境准备

Nginx版本：nginx v1.12.0
Keepalived版本：keepalived v1.2.1
Nginx-1：192.168.0.138  （Master）
Nginx-2：192.168.0.139 （Backup）

2、Nginx安装配置，Master、Backup服务器安装Nginx和keepalived

yum install -y pcre-devel 
wget -c http://nginx.org/download/nginx-1.12.0.tar.gz 
tar -xzf nginx-1.12.0.tar.gz
cd nginx-1.12.0 
sed -i -e 's/1.12.0//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
make
make install

3、Keepalived安装配置

wget http://www.keepalived.org/software/keepalived-1.2.1.tar.gz
tar  -xzvf  keepalived-1.2.1.tar.gz
cd keepalived-1.2.1 
./configure
make && make install 
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/
注意：如果正常安装keepalive不能使用，可能是在configure时需要指定内核，例如./configure --with-kernel-dir=/usr/src/kernels/2.6.32-431.el6.x86_64/

使用yum安装keepalive

yum install -y keepalived*

4、配置Keepalived，master端keepalived.conf内容如下（包括两个vrrp实例）：

! Configuration File for keepalived 
global_defs { 
  notification_email { 
      support@jfedu.net
 } 
    notification_email_from wgkgood@163.com 
    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 192.168.0.198 
vrrp_instance VI_1 { 
     state MASTER 
     interface ens33 
     lvs_sync_daemon_inteface ens33 
     virtual_router_id 151 
     priority 100 
     advert_int 5 
     #nopreempt 
     authentication { 
         auth_type  PASS 
         auth_pass  1111 
 
     } 
     virtual_ipaddress { 
         192.168.0.198 
     } 
     track_script { 
     chk_nginx 
    } 
}

#VIP2 192.168.0.199
vrrp_instance VI_2 { 
     state BACKUP
     interface ens33 
     lvs_sync_daemon_inteface ens33 
     virtual_router_id 152 
     priority 80 
     advert_int 5 
     #nopreempt 
     authentication { 
         auth_type  PASS 
         auth_pass  1111 
 
     } 
     virtual_ipaddress { 
         192.168.0.199 
     } 
     track_script { 
     chk_nginx 
    } 
}

backup端的keepalived.conf内容如下：

! Configuration File for keepalived 
global_defs { 
  notification_email { 
      support@jfedu.net
 } 
    notification_email_from wgkgood@163.com 
    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 192.168.0.198 
vrrp_instance VI_1 { 
     state BACKUP 
     interface ens33 
     lvs_sync_daemon_inteface ens33 
     virtual_router_id 151 
     priority 80
     advert_int 5 
     #nopreempt 
     authentication { 
         auth_type  PASS 
         auth_pass  1111 
 
     } 
     virtual_ipaddress { 
         192.168.0.198 
     } 
     track_script { 
     chk_nginx 
    } 
}

#VIP2 192.168.0.199
vrrp_instance VI_2 { 
     state MASTER
     interface ens33 
     lvs_sync_daemon_inteface ens33 
     virtual_router_id 152 
     priority 100 
     advert_int 5 
     #nopreempt 
     authentication { 
         auth_type  PASS 
         auth_pass  1111 
 
     } 
     virtual_ipaddress { 
         192.168.0.199 
     } 
     track_script { 
     chk_nginx 
    } 
}

5、如上配置还需要建立check_nginx脚本，用于检查本地Nginx是否存活，如果不存活，则kill keepalived实现切换。其中check_nginx.sh脚本内容如下：

#!/bin/bash 
#auto check nginx  process
NUM=`ps -ef|grep nginx|grep -vEc "check|grep"`
if [ $NUM -eq 0 ];then
    service keepalived stop
fi

6、通过查看日志/var/log/message，确认keepalived是否启动成功