LVS+Keepalived实现高可用集群 一
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
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