LVS+Keepalived介绍

LVS

LVS是LinuxVirtual 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     master.director       192.168.88.147

LVS-DR-BACKUP    slave.director         192.168.88.148

LVS-DR-VIP        lo:0                 192.168.88.100

WEB1-Realserver  webo.davy           192.168.88.134

WEB2-Realserver  web0.davy           192.168.88.138

GateWay                             192.168.88.253

主从director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

#wgethttp://www.linuxvirtualserver.org/software/kernel-2.6/ipvsadm-1.24.tar.gz

#wgethttp://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

#tarzxvf ipvsadm-1.24.tar.gz

#cdipvsadm-1.24

#make&& make install

#find /-name ipvsadm  # 查看ipvsadm的位置

#tarzxvf keepalived-1.1.15.tar.gz

#cdkeepalived-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/

#servicekeepalived start|stop     #做成系统启动服务方便管理.

3.在主负载均衡服务器上配置keepalived.conf

主调度器

#vi /etc/keepalived/keepalived.conf

! 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 {

192.168.88.100

}

}

virtual_server 192.168.88.100 80 {

delay_loop 6

lb_algo wrr

lb_kind DR

persistence_timeout 60

protocol TCP

real_server 192.168.88.134 80 {

weight 3

TCP_CHECK {

connect_timeout 10

nb_get_retry 3

delay_before_retry 3

connect_port 80

}

}

real_server 192.168.88.138 80 {

weight 3

TCP_CHECK {

connect_timeout 10

nb_get_retry 3

delay_before_retry 3

connect_port 80

}

}

}

从服务器

#vi/etc/keepalived/keepalived.conf

! 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 192.168.2.17080 {

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 192.168.2.17280 {

weight 3

TCP_CHECK {

connect_timeout 10

nb_get_retry 3

delay_before_retry 3

connect_port 80

}

}

}

#/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.

配置Realserver脚本.

#!/bin/bash

# Written by NetSeek

# description: Config realserver lo and applynoarp

WEB_VIP=192.168.88.100

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

case "$1" in

start)

ifconfig lo:0 $WEB_VIP netmask255.255.255.255 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/null2>&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:0device

# not found.

echo "LVS-DR real serverStopped."

else

echo "LVS-DR Running."

fi

;;

*)

# Invalid entry.

echo "$0: Usage: $0{start|status|stop}"

exit 1

;;

esac

exit 0

赋给权限 chmod 755realserver.sh

附上realserver机上的/etc/sysctl.conf：

# Kernel sysctl configuration file for Red HatLinux

#

# For binary values, 0 is disabled, 1 isenabled.  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 debuggingfunctionality of the kernel

kernel.sysrq = 0

# Controls whether core dumps will append thePID to the core filename.

# Useful for debugging multi-threadedapplications.

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 ipaddress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

启动realserver启本，在DR上可以查看LVS当前状态:

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

#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。