基于VMware的虚拟Linux集群搭建-lvs+keepalived

本文通过keepalived实现lvsserver的的双机热备和真实server之间的负载均衡。这方面的blog挺多，可是每一个人搭建集群的环境不同，遇到的问题也不同。本文简述配置的一些过程以及配置过程中遇到问题时的解决方式。

准本工作

1. 创建Linux虚拟机

本文是基于Vmare虚拟环境搭建集群的。所以首先在Vmare中创建一些虚拟机（安装一个Linux系统。其它的复制第一次安装的就可以）。本文创建4台虚拟机。网卡模式设置成桥接方式。这样能够保证虚拟机中的网络和主机IP在同一个网段。这种优点是，给每台虚拟机设完IP之后，就能够通过同一网段的还有一台主机登陆到Linux。就不用在虚拟机之间来回切换了。（Linux发行版本号为CentOS 5.5）

2. 配置yum库

若本机没有yum库，最好配置安装yum库，方便软件的安装

yum库创建基本步骤

①安装createrepo

②yum -y installl createrepo

③用createrepo创建

createrepo命令用于生成yum仓库所须要的一些基本配置信息。

详细请參考“yum库的安装于配置”

集群配置

1. 设置虚拟机IP

在Vmare虚拟机中虚拟四个Linux主机

LvsMaster：192.168.10.101

LvsBak: 192.168.10.102

RealServer1: 192.168.10.121

RealServer2: 192.168.10.122

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主机之间的拓扑关系图

2. 安装ipvsadm 和 keepalived

① 分别在LvsMaster和LvsBak上安装 ipvsadm

yum -y install *ipvsadm*

下载地址：wget http://www.linuxvirtualserver.org/software/kernel-2.6/ipvsadm-1.24.tar

②分别在LvsMaster和LvsBak上安装 keepalived

安装依赖库：yum install -y openssl openssl-devel

下载keepalived：wget http://www.keepalived.org/software/keepalived-1.2.6.tar.gz

tar zxvf keepalived-1.2.6.tar.gz

./configure --prefix=/usr/local/keepalived

make

make install

cp /usr/local/keepalived/sbin/keepalived /usr/sbin/

cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/

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

mkdir /etc/keepalived

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

③ 配置 keepalived

LvsMaster配置

global_defs {

notification_email {

540621626@qq.com #emial通知

}

notification_email_from 540621626@qq.com

smtp_server 192.168.200.1

smtp_connect_timeout 30

router_id LVS_DEVEL

}

vrrp_sync_group test {
#设置vrrp组

group {

loadbalance

}

}

vrrp_instance loadbalance {

state MASTER #设置主机类型，MASTER和BACKUP两种。必须大写，即太主机一台备用机

interface eth0 #设置对外服务网卡

virtual_router_id 51

priority 100 #设置优先级。备用主机的优先级要比主机低就可以

advert_int 1#设置同步时间间隔

authentication {#设置验证类型和password

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {#设置虚拟ip，即浮动ip

192.168.10.115

}

virtual_server 192.168.10.115 80 {

delay_loop 6 #健康检查时间间隔

lb_algo rr#负载调度算法，默觉得轮训算法

lb_kind DR#负载均衡转发规则，也就是IP转发规则，DR转发方式最快。可是全部机器必须在一个网段内。还有NAT和TUNEL两种转发方式

protocol TCP

real_server 192.168.10.121 80 {

weight 1

TCP_CHECK {

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

}

real_server 192.168.10.122 80 {

weight 1

TCP_CHECK {

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

}

}

LvsBakr配置

global_defs {

notification_email {

540621626@qqq.com

}

notification_email_from 540621626@qq.com

smtp_server 192.168.200.1

smtp_connect_timeout 30

router_id LVS_DEVEL

}

vrrp_sync_group test {

group {

loadbalance

}

}

vrrp_instance loadbalance {

state BACKUP

interface eth0

virtual_router_id 51

priority 99

advert_int 1

authentication {

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {

192.168.10.115

}

}

virtual_server 192.168.10.115 80 {

delay_loop 6

lb_algo rr

lb_kind DR

protocol TCP

real_server 192.168.10.121 80 {

weight 1

TCP_CHECK {

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

}

real_server 192.168.10.122 80 {

weight 1

TCP_CHECK {

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

}

}

④ 启动keepalived

LvsMastrer: /etc/init.d/keepalived start

LvsBak : /etc/init.d/keepalived start

查看启动状态

LvsMaster: tail -f /var/log/messages

LvsBak: tail -f /var/log/messages

用ip addr和ipvsadm查看路由情况

LvsMaster： ip addr

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LvsMaster: ipvsadm

LvsBak：ip addr

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LvsBak：ipvsadm

3. 设置RealServer1和RealServer2

① 编辑RealServe脚本

RealServer1和ResalServer2的脚本设置同样，都是realserver.sh，设置脚本例如以下

SNS_VIP=192.168.10.115

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

case "$1" in

start)

ifconfig lo:0 $SNS_VIP netmask 255.255.255.255 broadcast $SNS_VIP up

/sbin/route add -host $SNS_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 $SNS_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"

;;

*)

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

exit 1

esac

exit 0

脚本编辑完毕后启动realserver.sh

RealServer1： ./realserver.sh start

RealServer2： ./realserver.sh start

查看IP

② 在RealServer1和RealServer2上安装apache

安装

yum -y install httpd

配置

ServerName www.example.com

NameVirtualHost 192.168.10.121:80

<VirtualHost 192.168.10.121:80>

DocumentRoot /var/www/html

ServerName www.example.com

</VirtualHost>

在 /var/www/hmtl/下加入index.html測试主页

启动apache ：/etc/init.d/httpd start

4. 測试负载均衡和双机热备

用ipvsadm 查看 LvsMaster 和 LvsBak的路由情况

LvsMaster: ipvsadm

LvsBak: ipvsadm

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5. 配置过程中应注意的问题

① 配置keepalvied应注意的问题

LvsMaster和LvsBak仅仅有两处不同

state MASTER | BACKUP （主Lvs是MASTER，备用Lv是BACKUP）

priority 100 | 90 （主Lvs是100。备用LVS仅仅要小于100就可以）

② 要关闭iptables或者开启对应的服务port，否则无法通过浏览器訪问