试验环境 ubuntu 20.04

一、安装 nginx 和 keepalived

apt-get install -y nginx keepalived

二、配置 nginx

user root;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
    worker_connections 768;
}

http {

    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;

    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3; # Dropping SSLv3, ref: POODLE
    ssl_prefer_server_ciphers on;

    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log;

    gzip on;

    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;
}

三、配置 keepalived

global_defs {
   notification_email {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id NGINX_MASTER
}
# 检测脚本地址
vrrp_script check_nginx {
    script "/etc/keepalived/check_nginx.sh"
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens160          # 指定网卡
    virtual_router_id 51
    priority 90               # 权重，主节点比备节点大
    advert_int 1              # 指定VRRP 心跳包通告间隔时间，默认1秒 
    authentication {
        auth_type PASS
        auth_pass 1111      
    }

    # 虚拟IP
    virtual_ipaddress {
        192.168.17.199/24
    }
    track_script {
        check_nginx           #  执行一个检测脚本
    }
}

check_nginx.sh

#!/bin/bash
# 判断Nginx是否存活  根据物理机情况而定
counter=$(ps -ef |grep "/usr/sbin/nginx" | egrep -cv "grep|$$" )
if [ $counter -eq 0 ]; then
    # 如果不存活则尝试启动Nginx
    service nginx start
    sleep 2
    # 等待2秒后再次获取一次Nginx状态
    counter=$(ps -ef |grep "/usr/sbin/nginx" | egrep -cv "grep|$$" )
    # 再次进行判断，如Nginx还不存活则停止Keepalived，让地址进行漂移
    if [ $counter -eq 0 ]; then
        service  keepalived stop
    fi
fi

四、重启服务

service nginx restart
service keepalived restart

五、测试

• 主节点 ip addr
  可以看到已经有 vip 了

root@node1:~# ip addr
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:96:5d:26 brd ff:ff:ff:ff:ff:ff
    inet 192.168.17.131/24 brd 192.168.17.255 scope global ens160
       valid_lft forever preferred_lft forever
    inet 192.168.17.199/24 scope global secondary ens160
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe96:5d26/64 scope link
       valid_lft forever preferred_lft forever

• 主节点暂停 keepalived

service keepalived stop

• 查看备节点 ip
  可以看到 vip 已漂移

root@node2:~# ip addr
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:ed:db:ae brd ff:ff:ff:ff:ff:ff
    inet 192.168.17.132/24 brd 192.168.17.255 scope global ens160
       valid_lft forever preferred_lft forever
    inet 192.168.17.199/24 scope global secondary ens160
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:feed:dbae/64 scope link
       valid_lft forever preferred_lft forever