ngixn负载均衡高可用-主备切换keepalived实现

1.环境

• 操作系统

  CentOS release 6.10 (Final)

• 主机规划

  IP	用途
  192.168.47.110	nginx + keepalived master(主)
  192.168.47.21	nginx + keepalived backup(备)
  192.168.47.20	vip，对外提供服务访问IP

• 访问流程
  

2.安装keepalived

• 主和备机都需要安装好nginx，具体安装步骤可参考博文：
  https://blog.csdn.net/cen50958/article/details/89645100
• 主机和备机都需要安装keeplive

  yum install keepalived -y

3.1 keepalived监控nginx存活脚本

#!/bin/bash
counter=$(ps -C nginx --no-heading|wc -l)
if [ "${counter}" = "0" ]; then
    /usr/local/nginx/sbin/nginx
    sleep 2
    counter=$(ps -C nginx --no-heading|wc -l)
    if [ "${counter}" = "0" ]; then
        /etc/init.d/keepalived stop
    fi
fi

3.2 主keepalived配置文件

vim /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {
   notification_email {
     [email protected]
   }
   notification_email_from [email protected]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

vrrp_script chk_nginx {      
    script "/server/scripts/chk_nginx.sh"  
    interval 2                 
    weight -5                 
    fall 2                  
    rise 1           
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 200
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.47.20
    }
    track_script {                     
       chk_nginx             
    }
}

3.3 备keepalived配置文件

! Configuration File for keepalived

global_defs {
   notification_email {
     [email protected]
   }
   notification_email_from [email protected]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.47.20
    }
} 

3.4 keepalived开机启动

echo "/etc/init.d/keepalived start" >> /etc/rc.local

4.启动keepalived

/etc/init.d/keepalived start

• 查看主服务器IP
  

• 查看备服务器IP
  

• 测试：关闭主服务器nginx