ipvsadm+keepalived 实现高可用负载均衡

一.使用系统Red Hat Enterprise Linux Server release 5.4

二.安装环境

  1.说明

    realserver:192.168.1.11

    realserver:192.168.1.12

    lvs控制机 MASTER:192.168.1.100

             BACKUP:192.168.1.101

    虚拟VIP：192.168.1.200

    其中：realserver上只需要简单的安装apache即可

         lvs控制机需要安装：ipvsadm，keepalived

  2.lvs控制机安装，主备机分别安装ipvsadm

    实现LVS/DR最重要的两个东西是ipvs内核模块和ipvsadm工具包，现在的系统已经包含ip_vs模块

    1）检查内核模块，看一下ip_vs 是否被加载

       # lsmod |grep ip_vs

       如果没有显示，则说明没有加载，执行命令 modprobe ip_vs 就可以把ip_vs模块加载到内核

       # lsmod |grep ip_vs

         ip_vs    35009    0

    2）安装ipvsadm

      先把目录/usr/src/kernels/2.6.18-164.el5-x86_64链接为/usr/src/linux，命令如下

      ln –s /usr/src/kernels/2.6.18-164.el5-x86_64 /usr/src/linux

      解压ipvsadm-1.24.tar.gz,执行"make;make install”完成安装。

       vi lvsdr

       #!/bin/bash
       RIP1=192.168.1.11
       RIP2=192.168.1.12
 
       VIP1=192.168.1.200

       /etc/rc.d/init.d/functions
 
       case "$1" in
 
       start)
           echo " start LVS of DirectorServer"
 
          # set the Virtual IP Address and sysctl parameter
          /sbin/ifconfig eth0:0 $VIP1 broadcast $VIP1 netmask 255.255.255.255 up
          #/sbin/ifconfig eth0:1 $VIP2 broadcast $VIP2 netmask 255.255.255.255 up
          /sbin/route add -host $VIP1 dev eth0:0
          #/sbin/route add -host $VIP2 dev eth0:1
          echo "1" >/proc/sys/net/ipv4/ip_forward
 
          #Clear IPVS table
          /sbin/ipvsadm -C
 
          #set LVS
          #Web Apache
          /sbin/ipvsadm -A -t $VIP1:80 -s rr -p 120
          /sbin/ipvsadm -a -t $VIP1:80 -r $RIP1:80 -g
          /sbin/ipvsadm -a -t $VIP1:80 -r $RIP2:80 -g
 
          #Run LVS
          /sbin/ipvsadm
      ;;
      stop)
          echo "close LVS Directorserver"
          echo "0" >/proc/sys/net/ipv4/ip_forward
          /sbin/ipvsadm -C
          /sbin/ifconfig eth0:0 down
      ;;
      *)
          echo "Usage: $0 {start|stop}"
          exit 1
      esac

    4)主备机上分别安装keepalived

      tar zxf keepalived-1.1.17.tar.gz

      cd keepalived-1.1.17

      ./configure --prefix=/usr/local/keepalive

      make && make install

      mkdir -p /etc/keepalived/

      vi keepalived.conf以下配置文件

! Configuration File for keepalived
global_defs {
   router_id LVS_DEVEL
}
 
vrrp_instance VI_1 {
    state MASTER         #备份服务器上将MASTER改为BACKUP
    interface eth0       #HA监测网络接口
    virtual_router_id 51 #主、备机的virtual_router_id必须相同
    priority 90          #主、备机取不同的优先级，主机值较大，备份机值较小
    advert_int 1         #VRRP Multicast广播周期秒数
    authentication {
        auth_type PASS   #VRRP认证方式
        auth_pass 1111   #VRRP口令字
    }
    virtual_ipaddress { 
        192.168.1.200    #LVS虚拟地址
    }
}
 
virtual_server 192.168.1.200 80 {
    delay_loop 2
    lb_algo rr
    lb_kind DR  
    protocol TCP
 
  real_server 192.168.1.11 80 {
        weight 1
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
  real_server 192.168.1.12 80 {
        weight 1
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

三.分别启动主备机上的lvs脚本和keepalived

   sh lvsdr start

   /usr/local/keepalived/sbin/keepalived -D

四.测试

   停掉主机ipvsadmn和keepalived，从机立即接管服务

   启动主机服务，主机负载均衡生效