keepalived + nginx 实现高可用方案

! Configuration File for keepalived

global_defs {
   router_id LB111
}

vrrp_script chk_nginx {
   # 具体的脚本
   script "/etc/keepalived/nginx_check.sh"
   interval 2 # 2s执行一次 
   weight -20 # 失败一次 则优先级 -20
}

vrrp_instance VI_1 {
    state MASTER
    interface ens160
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.16.225.200
    }
    # 指定脚本
    track_script {
      chk_nginx
    }
}

! Configuration File for keepalived

global_defs {
   router_id LB111
}

vrrp_script chk_nginx {
   script "/etc/keepalived/nginx_check.sh"
   interval 2
   weight -20
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens160
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
       172.16.225.200
    }

    track_scrip {
      chk_nginx
    }
}

#!/bin/bash
status=$(ps -C nginx --no-heading|wc -l)
if [ "${status}" = "0" ]; then
            # 尝试启动一次
            systemctl start nginx
        # 再次检查ngixn 进程
        status2=$(ps -C nginx --no-heading|wc -l)
        if [ "${status2}" = "0"  ]; then
                # 关闭 keepalived 
                systemctl stop keepalived
        fi
fi

# 给脚本一个 可执行的权限
chmode +x /etc/keepalived/nginx_check.sh 

# 重启或者启动 keepalived 
systemctl restart keepalived

# 临时关闭
setenforce 0

#永久关闭
sed -i 's/SELINUX=enforcing/\SELINUX=disabled/' /etc/selinux/config

# 关闭 nginx 
./nginx -s stop

# 此时查看 keepalived 的状态就是 dead了
systemctl status keepalived

● keepalived.service - LVS and VRRP High Availability Monitor
   Loaded: loaded (/usr/lib/systemd/system/keepalived.service; disabled; vendor preset: disabled)
   Active: inactive (dead)