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LVS+Keepalived实现高可用集群

2014-12-05 13:29 288 查看
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



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
fee7
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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