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LVS+Keepalived实现高可用集群

Linux 苏 demo 2830℃ 0评论

操作系统平台：CentOS5.2
软件：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

1

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.gz2. 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 {

    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 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 {

    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 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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