使用keepalived搭建高可用集群

使用keepalived搭建高可用集群

• 概览

  • 涉及理论知识点：VRRP协议 https://blog.youkuaiyun.com/zhyvodka/article/details/41800399

• 准备工作

  • 三台机器恢复快照，抹掉LVS的实验痕迹

• 规划：

  aming01 web1
  aming02 Nginx负载均衡1
  aming03 Nginx负载均衡2，同时也是web2

• 搭建Nginx负载均衡

  • 在aming02和aming03上都要做

  • 安装Nginx------配置yum源------vi /etc/yum.repos.d/nginx.repo

    [nginx]
    name=nginx repo
    baseurl=http://nginx.org/packages/centos/7/$basearch/
    gpgcheck=0
    enabled=1

  • 安装：yum install -y nginx

  • 负载均衡配置：vim /etc/nginx/conf.d/bbs_proxy.conf

    upstream bbs 
    {
    	ip_hash; 
    	server 192.168.222.128:80; 
    	server 192.168.222.130:8080;
    }
    server
    {
    	listen 80;
    	server_name bbs.aminglinux.cc;
    	location /
    	{
    	    proxy_pass http://bbs;
    	    proxy_set_header Host $host;
    	    proxy_set_header X-Real-IP $remote_addr;
    	    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    	}
    }

  • 补充：关于upstream配置 https://blog.youkuaiyun.com/zwhfyy/article/details/70856035

• 安装配置keepalived

  • 在aming02和aming03上都要做
  • 安装：yum install -y keepalived

  • 配置：vi /etc/keepalived/keepalived.conf

    global_defs {
        notification_email {
        xxxx@126.com //定义接收邮件人
    }
    notification_email_from //定义发邮件地址（实际没有）
        smtp_server 127.0.0.1
        smtp_connect_timeout 30
        router_id 001
    }
    
    vrrp_script chk_nginx {
        script "/usr/local/sbin/check_ng.sh" //此脚本为监控nginx服务的
        interval 3
    }
    
    vrrp_instance aminglinux {
        state MASTER
        interface ens33 //网卡
        virtual_router_id 001
        priority 100 //权重100，此数值要大于backup
        advert_int 1
        authentication {
    	auth_type PASS
    	auth_pass aminglinux //定义密码
        }
        virtual_ipaddress {
    	192.168.222.100 //定义VIP
        }
    
        track_script {
    	chk_nginx //定义监控脚本，这里和上面vrr_script后面的字符串保持一致
        }
    }
    

  • 补充： keepalived中如何配置第三方邮件告警 https://blog.youkuaiyun.com/HzSunshine/article/details/62052398

  • 编写监控Nginx的脚本：vim /usr/local/sbin/check_ng.sh

    #!/bin/bash#时间变量，用于记录日志
    d=`date --date today +%Y%m%d_%H:%M:%S`
    #计算nginx进程数量
    n=`ps -C nginx --no-heading|wc -l`
    #如果进程为0，则启动nginx，并且再次检测nginx进程数量，#如果还为0，说明nginx无法启动，此时需要关闭keepalived
    if [ $n -eq 0 ]
    then
        systemctl start nginx  #启动命令
        n2=`ps -C nginx --no-heading|wc -l`
        if [ $n2 -eq "0" ]; then
    	echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log
    	systemctl stop keepalived
        fi
    fi

  • 修改权限

    chmod 755 /usr/local/sbin/check_ng.sh

  • 启动keepalived

    • 查防火墙, 要保证VRRP协议放行，SElinux要关闭

      iptables -A INPUT -p vrrp -j ACCEPT
      setenforce 0

    • 启动

      systemctl start keepalived

    • 测试

    • 测试点：

      手动停止aming01上的nginx服务
      手动停止aming01上的keepalived服务
      设置防火墙禁止VRRP协议