LVS

• 介绍
  • 第四层开始负载(可以建立到三层负载)
  • 第四层负载
    • Socket进必须连LVS
• 模式
  • TUN
    • lvs负载均衡器将请求包发给物理服务器，后者将应答包直接发给用户
  • NAT
    • 请求和应答都经过lvs
  • DR
    • 不要隧道结构的tun
  • FULLNAT模式
• 使用
  • DR模式 centos6
  • yum install-y gcc gcc-c++ makepcre pcre-devel kernel-devel openssl-devel libnl-devel popt-devel
  • modprobe -l |grep ipvs
    • 检查内核是否集成
  • echo “1” > /proc/sys/net/ipv4/ip_forward
    • 开启路由转发
  • 安装ipvsadm
    • http://www.linuxvirtualserver.org/software/kernel-2.6/ipvsadm-1.26.tar.gz
  • 安装keepalived

    • http://www.keepalived.org/software/keepalived-1.2.7.tar.gz
      ./configure --prefix=/usr/local/keepalived
       
      cp  /usr/local/keepalived/etc/rc.d/init.d/keepalived        /etc/init.d/
      cp /usr/local/keepalived/etc/sysconfig/keepalived        /etc/sysconfig/
      mkdir /etc/keepalived/
      cp /usr/local/keepalived/etc/keepalived/keepalived.conf        /etc/keepalived/
      cp /usr/local/keepalived/sbin/keepalived        /usr/sbin/

    • 配置文件/etc/keepalived/keepalived.conf

      • ! Configuration File forkeepalived
        global_defs {
        notification_email {
        test@sina.com    #故障接受联系人
        }
        notification_email_from admin@test.com  #故障发送人
        smtp_server 127.0.0.1  #本机发送邮件
        smtp_connect_timeout 30
        router_id LVS_MASTER  #BACKUP上修改为LVS_BACKUP
        }
        vrrp_instance VI_1 {
        state MASTER    #BACKUP上修改为BACKUP
        interface eth0
        virtual_router_id 51  #虚拟路由标识，主从相同
        priority 100  #BACKUP上修改为90
        advert_int 1
        authentication {
        auth_type PASS
        auth_pass 1111  #主从认证密码必须一致
        }
        virtual_ipaddress {    #Web虚拟IP（VTP）
        172.0.0.10
        }
        }
        virtual_server 172.0.0.10 80 { #定义虚拟IP和端口
        delay_loop 6    #检查真实服务器时间，单位秒
        lb_algo rr      #设置负载调度算法，rr为轮训
        lb_kind DR      #设置LVS负载均衡DR模式
        persistence_timeout 50 #同一IP的连接60秒内被分配到同一台真实服务器
        protocol TCP    #使用TCP协议检查realserver状态
        real_server 172.0.0.13 80 {  #第一个web服务器
        weight 3          #节点权重值
        TCP_CHECK {      #健康检查方式
        connect_timeout 3 #连接超时
        nb_get_retry 3    #重试次数
        delay_before_retry 3  #重试间隔/S
        }
        }
        real_server 172.0.0.14 80 {  #第二个web服务器
        weight 3
        TCP_CHECK {
        connect_timeout 3
        nb_get_retry 3
        delay_before_retry 3
            }
        }
        }

    • service keepalived restart
  • 启动脚本 /etc/init.d/real.sh

    • #description : start realserver
      VIP=172.0.0.10
      . /etc/init.d/functions
      case "$1" in
      start)
      /sbin/ifconfig lo:0 $VIP broadcast $VIP netmask 255.255.255.255 up
      echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore
      echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce
      echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore
      echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce
      echo "LVS RealServer Start OK"
      ;;
      stop)
      /sbin/ifconfig lo:0 down
      echo "0" >/proc/sys/net/ipv4/conf/lo/arp_ignore
      echo "0" >/proc/sys/net/ipv4/conf/lo/arp_announce
      echo "0" >/proc/sys/net/ipv4/conf/all/arp_ignore
      echo "0" >/proc/sys/net/ipv4/conf/all/arp_announce
      echo "LVS RealServer Stoped OK"
      ;;
      *)
      echo "Usage: $0 {start|stop}"
      exit 1
      esac

  • o→ 开机启动
    • chmod +x /etc/init.d/real.sh
    • /etc/init.d/real.sh start
    • echo “/etc/init.d/real.sh start” >> /etc/rc.local
  • o→ 测试
    • service httpd start
    • echo “1” > /var/www/html/index.html
    • service iptables stop
    • setenforce 0
      • 关闭selinux
  • o→ 其他命令
    • ipvsadm -ln
      • 集群中服务器ip信息
    • ip addr
      • 显示VIP当前绑定的服务器
    • tail -f /var/log/messages
      • 日志