Keepalived

Keepalived的作⽤是检测服务器的状态，如果有⼀台web服务器宕机，或⼯作出现故障，Keepalived将检测到，并将有故障的服务器从系统中剔除，同时使⽤其他服务器代
替该服务器的⼯作，当服务器⼯作正常后Keepalived⾃动将服务器加⼊到服务器群中，这些⼯作全部⾃动完成，不需要⼈⼯⼲涉，需要⼈⼯做的只是修复故障的服务器。
⼀个监控+⾃愈的软件

VRRP协议

http://www.keepalived.org/download.html
wget http://www.keepalived.org/software/keepalived-2.0.8.tar.

#cat keepalived_install.sh
#!/bin/bash
pkg=keepalived-2.0.8.tar.g
tar xf $pkg
yum -y install kernel-devel
ln -s /usr/src/kernels/3.10.0-862.14.4.el7.x86_64/ /usr/src/linux
cd keepalived-2.0.8/
yum install openssl-* -y
./configure --prefix=/usr/local/keepalived
make
make install
mkdir -pv /etc/keepalived
cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
ln -s /usr/local/keepalived/sbin/keepalived /sbin

 

yum install keepalived -y

 

 

keepalived 始终保证负载服务器有一台可以正常工作：原理

keepalived对主 网卡设置虚拟ip，同时用户访问真实ip,
对每一台
nginx监听虚拟ip,但是这个虚拟ip由keep根据niginx状态切换。
服务监听网卡上没有的ip地址：

echo 'net.ipv4.ip_nonlocal_bind = 1' >>/etc/sysctl.conf
sysctl -p

 

配置Nginx集群

upstream web {
  server 192.168.10.42 max_fails=2 fail_timeout=3;
  server 192.168.10.43 max_fails=2 fail_timeout=3；
  server {
  listen 192.168.10.213：80;
  server_name localhost;
  location / {
  proxy_pass http://web;
  }
 

 

 

配置keepalived

#cat /etc/keepalived/keepalived.conf

192.168.10.211

192.168.10.212

! Configuration File for keepalived

global_defs {
   router_id NGINX_DEVEL
}
vrrp_script check_nginx {
    # 定义监控脚本
    script "/etc/keepalived/nginx_pid.sh"
    interval 2
    weight 2
}  
vrrp_instance nginx {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1                          # 主给从  每隔一秒发送组播包
    authentication {
        auth_type PASS
        auth_pass 1111
    } 
    track_script { 
　　    check_nginx
　　}
    virtual_ipaddress { 
　　    192.168.10.213/24 dev eth0 label eth0:1 
　　} 
}

 

 就这三处不一致,虚IP，不存在，但在一个网段

 

 

关联脚本 nginx_pid.sh

将nginx与keepalived建立联系；解决nginx挂掉，keepalived虚IP还存在

#chmod 755 /etc/keepalived/nginx_pid.sh
#cat /etc/keepalived/nginx_pid.sh

#!/bin/bash
 
web_info=$(ps -ef|grep [n]ginx|wc -l)
if [ $web_info -lt 2 ]
then
    /etc/init.d/keepalived stop
fi

 

systemctl start keepalived
/etc/init.d/keepalived status

 

 

双主配置

vrrp_instance gorup01 {
	state MASTER
	interface eth0
	virtual_router_id 51
	priority 150
	advert_int 1
	authentication {
		auth_type PASS
		auth_pass 1111
	}
	virtual_ipaddress {
		10.0.0.3/24 dev eth0 label eth0:1
   }
}
vrrp_instance gorup02 {
	state BACKUP
	interface eth0
	virtual_router_id 52
	priority 100
	advert_int 1
	authentication {
		auth_type PASS
		auth_pass 1111
	}
	virtual_ipaddress {
		10.0.0.4/24 dev eth0 label eth0:1
	}
}

　　

vrrp_instance gorup01 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        10.0.0.3/24 dev eth0 label eth0:1
   }
}
vrrp_instance gorup02 {
    state MASTER
    interface eth0
    virtual_router_id 52
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        10.0.0.4/24 dev eth0 label eth0:1
    }
}