LVS+Keepalived

LVS+Keepalived 介绍

LVS

LVS是Linux Virtual Server的简写,意即Linux虚拟服务器,是一个虚拟的服务器集群系统。本项目在1998年5月由章文嵩博士成立,是中国国内最早出现的自由软件项目之一。目前有三种IP负载均衡技术(VS/NAT、VS/TUN和VS/DR);
十种调度算法(rrr|wrr|lc|wlc|lblc|lblcr|dh|sh|sed|nq)。
Keepalvied
Keepalived在这里主要用作RealServer的健康状态检查以及LoadBalance主机和BackUP主机之间failover的实现



IP配置信息:

  • LVS-DR-Master          192.168.2.166 
  • LVS-DR-BACKUP          192.168.2.167 
  • LVS-DR-VIP             192.168.2.170        
  • WEB1-Realserver        192.168.2.171 
  • WEB2-Realserver        192.168.2.172 
  • GateWay                192.168.2.253
    安装LVS和Keepalvied软件包
       
    1. 下载相关软件包 
    #mkdir /usr/local/src/lvs
    #cd /usr/local/src/lvs
    #wget 
    http://www.linuxvirtualserver.org/software/kernel-2.6/ipvsadm-1.24.tar.gz
    #wget 
    http://www.keepalived.org/software/keepalived-1.1.15.tar.gz

    2. 安装LVS和Keepalived 
  • #lsmod |grep ip_vs
  • #uname -r
  • 2.6.18-53.el5PAE
  • #ln -s /usr/src/kernels/2.6.18-53.el5PAE-i686/  /usr/src/linux
  • #tar zxvf ipvsadm-1.24.tar.gz
  • #cd ipvsadm-1.24
  • #make && make install
  • #find / -name ipvsadm  # 查看ipvsadm的位置
  • #tar zxvf keepalived-1.1.15.tar.gz
  • #cd keepalived-1.1.15
  • #./configure  && make && make install
  • #find / -name keepalived  # 查看keepalived位置                
  •     
  • #cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
  • #cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
  • #mkdir /etc/keepalived
  • #cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/
  • #cp /usr/local/sbin/keepalived /usr/sbin/
  • #service keepalived start|stop     #做成系统启动服务方便管理.
    四. 配置LVS实现负载均衡

      1. LVS-DR,配置LVS脚本实现负载均衡 

    vi /usr/local/sbin/lvs-dr.sh

    #!/bin/bash
    # description: start LVS of DirectorServer
    #Written by :NetSeek 
    http://www.linuxtone.org
    GW=192.168.2.253

    # website director vip.
    WEB_VIP=192.168.2.170
    WEB_RIP1=192.168.2.171
    WEB_RIP2=192.168.2.172
    . /etc/rc.d/init.d/functions

    logger $0 called with $1

    case "$1" in

    start)
            # Clear all iptables rules.
            /sbin/iptables -F
            # Reset iptables counters.
            /sbin/iptables -Z
            # Clear all ipvsadm rules/services.
            /sbin/ipvsadm -C

    #set lvs vip for dr
            /sbin/ipvsadm --set 30 5 60
            /sbin/ifconfig eth0:0 $WEB_VIP broadcast $WEB_VIP netmask 255.255.255.255 up
            /sbin/route add -host $WEB_VIP dev eth0:0
            /sbin/ipvsadm -A -t $WEB_VIP:80 -s wrr -p 3
            /sbin/ipvsadm -a -t $WEB_VIP:80 -r $WEB_RIP1:80 -g -w 1
            /sbin/ipvsadm -a -t $WEB_VIP:80 -r $WEB_RIP2:80 -g -w 1
            touch /var/lock/subsys/ipvsadm >/dev/null 2>&1
            
            # set Arp
            /sbin/arping -I eth0 -c 5 -s $WEB_VIP $GW >/dev/null 2>&1 
           ;;
    stop)
            /sbin/ipvsadm -C
            /sbin/ipvsadm -Z
            ifconfig eth0:0 down
            route del $WEB_VIP  >/dev/null 2>&1
            rm -rf /var/lock/subsys/ipvsadm >/dev/null 2>&1
            /sbin/arping -I eth0 -c 5 -s $WEB_VIP $GW
            echo "ipvsadm stoped"
           ;;

    status)

            if [ ! -e /var/lock/subsys/ipvsadm ];then
                    echo "ipvsadm is stoped"
                    exit 1
            else
                    ipvsadm -ln
                    echo "..........ipvsadm is OK."
            fi
          ;;

    *)
            echo "Usage: $0 {start|stop|status}"
            exit 1
    esac

    exit 0
    2. 配置Realserver脚本. 

    #!/bin/bash
    # Written by NetSeek 
    # description: Config realserver lo and apply noarp 
    WEB_VIP=192.168.2.170

    . /etc/rc.d/init.d/functions

    case "$1" in
    start)
           ifconfig lo:0 $WEB_VIP netmask 255.255.255.255 broadcast $WEB_VIP
           /sbin/route add -host $WEB_VIP dev lo:0
           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
           sysctl -p >/dev/null 2>&1
           echo "RealServer Start OK"

           ;;
    stop)
           ifconfig lo:0 down
           route del $WEB_VIP >/dev/null 2>&1
           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 "RealServer Stoped"
           ;;
    status)
            # Status of LVS-DR real server.
            islothere=`/sbin/ifconfig lo:0 | grep $WEB_VIP`
            isrothere=`netstat -rn | grep "lo:0" | grep $web_VIP`
            if [ ! "$islothere" -o ! "isrothere" ];then
                # Either the route or the lo:0 device
                # not found.
                echo "LVS-DR real server Stopped."
            else
                echo "LVS-DR Running."
            fi
    ;;
    *)
            # Invalid entry.
            echo "$0: Usage: $0 {start|status|stop}"
            exit 1
    ;;
    esac
    exit 0

    附上realserver机上的/etc/sysctl.conf:

    # Kernel sysctl configuration file for Red Hat Linux
    #
    # For binary values, 0 is disabled, 1 is enabled.  See sysctl(8) and
    # sysctl.conf(5) for more details.
    # Controls IP packet forwarding
    net.ipv4.ip_forward = 1
    # Controls source route verification
    net.ipv4.conf.default.rp_filter = 1
    # Do not accept source routing
    net.ipv4.conf.default.accept_source_route = 0
    # Controls the System Request debugging functionality of the kernel
    kernel.sysrq = 0
    # Controls whether core dumps will append the PID to the core filename.
    # Useful for debugging multi-threaded applications.
    kernel.core_uses_pid = 1
    net.ipv4.conf.lo.arp_ignore = 1
    net.ipv4.conf.lo.arp_announce = 2
    net.ipv4.conf.all.arp_ignore = 1
    net.ipv4.conf.all.arp_announce = 2
    或者采用secondary ip address方式配置
    # vi /etc/sysctl.conf 

    添加以下内容如上所示:

    net.ipv4.conf.lo.arp_ignore = 1
    net.ipv4.conf.lo.arp_announce = 2
    net.ipv4.conf.all.arp_ignore = 1
    net.ipv4.conf.all.arp_announce = 2
    #sysctl –p
    #ip addr add 61.164.122.8/32 dev lo
    #ip add list 查看是否绑定
    3. 启动lvs-dr脚本和realserver启本,在DR上可以查看LVS当前状态:
    #watch ipvsadm –ln

    五.利用Keepalvied实现负载均衡和和高可用性

    1.配置在主负载均衡服务器上配置keepalived.conf
    #vi /etc/keepalived/keepalived.conf (主调度器)
    ! Configuration File for keepalived
    global_defs {
       notification_email {
         
    [email protected]
         
    [email protected]
         
    [email protected]
       }
       notification_email_from 
    [email protected]
       smtp_server 127.0.0.1
       smtp_connect_timeout 30
       router_id LVS_DEVEL
    }
    vrrp_instance VI_1 {
        state MASTER
        interface eth0
        virtual_router_id 51
        priority 100
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass 1111
        }
        virtual_ipaddress {
            192.168.2.170
        }
    }
    virtual_server 192.168.2.170 80 {
        delay_loop 6
        lb_algo wrr
        lb_kind DR
        persistence_timeout 60
        protocol TCP
       
        real_server 192.168.2.171 80 {
            weight 3             
            TCP_CHECK {
            connect_timeout 10   
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80

        }
        real_server 192.168.2.172 80 {
            weight 3
            TCP_CHECK {
            connect_timeout 10
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
            }
         }
    }

    在备用调度器上:
    #vi /etc/keepalived/keepalived.conf (备用调度器)
    ! Configuration File for keepalived
    global_defs {
       notification_email {
         
    [email protected]
         
    [email protected]
         
    [email protected]
       }
       notification_email_from 
    [email protected]
       smtp_server 127.0.0.1
       smtp_connect_timeout 30
       router_id LVS_DEVEL
    }
    vrrp_instance VI_1 {
        state BACKUP
        interface eth0
        virtual_router_id 51
        priority 99
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass 1111
        }
        virtual_ipaddress {
            192.168.2.170
        }
    }
    virtual_server 192.168.2.170 80 {
        delay_loop 6
        lb_algo wrr
        lb_kind DR
        persistence_timeout 60
        protocol TCP
       
        real_server 192.168.2.171 80 {
            weight 3             
            TCP_CHECK {
            connect_timeout 10   
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80

        }
        real_server 192.168.2.172 80 {
            weight 3
            TCP_CHECK {
            connect_timeout 10
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
            }
         }
    }

    2. BACKUP服务器同上配置,先安装lvs再按装keepalived,仍后配置/etc/keepalived/keepalived.conf,只需将红色标示的部分改一下即可.
    3. vi /etc/rc.local
       #/usr/local/sbin/lvs-dr.sh  将lvs-dr.sh这个脚本注释掉。
       #/usr/local/sbin/lvs-dr.sh stop 停止lvs-dr脚本

       #/etc/init.d/keepalived start  启动keepalived 服务,keepalived就能利用keepalived.conf 配
       置文件,实现负载均衡和高可用.
    4. 查看lvs服务是否正常
      
    #watch ipvsadm –ln 
    IP Virtual Server version 1.2.1 (size=4096)
    Prot LocalAddressort Scheduler Flags
      -> RemoteAddressort           Forward Weight ActiveConn InActConn
    TCP  61.164.122.8:80 wrr persistent 60
      -> 61.164.122.10:80            Route   3      0          0
      -> 61.164.122.9:80             Route   3      0          0
    复制代码
    #tail –f /var/log/message  监听日志,查看状态,测试LVS负载均衡及高可用性是否有效。
    5.停Master服务器的keepalived服务,查看BAKCUP服务器是否能正常接管服务。
    四.相关参考
    1.LVS 基础知识汇总
    LVS的算法介绍            
    http://www.linuxtone.org/viewthread.php?tid=69
    学习LVS的三种转发模式     
    http://www.linuxtone.org/viewthread.php?tid=77
    LVS中的IP负载均衡技术     
    http://www.linuxtone.org/viewthread.php?tid=68
    更多的请到
    http://www.linuxtone.org
    负载均衡版查看
    Keepalived 相关参考资料。
       
    http://www.keepalived.org/documentation.html

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