LVS+Keepalived实现高可用集群 一

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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 ...

　　　　

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:

1.    LVS-DR-Master          192.168.2.166

2.    LVS-DR-BACKUP          192.168.2.167

3.    LVS-DR-VIP             192.168.2.170

4.    WEB1-Realserver        192.168.2.171

5.    WEB2-Realserver        192.168.2.172

6.    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

1.    #lsmod |grep ip_vs

2.    #uname -r

3.    2.6.18-53.el5PAE

4.    #ln -s /usr/src/kernels/2.6.18-53.el5PAE-i686/  /usr/src/linux

5.

6.    #tar zxvf ipvsadm-1.24.tar.gz

7.    #cd ipvsadm-1.24

8.    #make && make install

9.    #find / -name ipvsadm  # 查看ipvsadm的位置

10.

11.    #tar zxvf keepalived-1.1.15.tar.gz

12.    #cd keepalived-1.1.15

13.    #./configure  && make && make install

14.    #find / -name keepalived  # 查看keepalived位置

15.

16.    #cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/

17.    #cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/

18.    #mkdir /etc/keepalived

19.    #cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/

20.    #cp /usr/local/sbin/keepalived /usr/sbin/

21.    #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