LVS+Heartbeat+memcached+nfs Web集羣的構建

1、說明

LVS 是Linux Virtual  Server，主要用來實現後端服務的負載均衡，用源碼包ipvsadm構建，本文使用基於tunneling模式的轉發機制，調度算法使用 weighted Least-connected(wlc),即每一個新的鏈接被分配到負擔最小的服務器。

Heartbeat 是一種心跳檢測機制，主要用來實現雙機互備份，它的接管工做是經過ARP欺騙的手段來完成的。

Memcached memcached不是memcache,它是高性能的，分佈式的內存對象緩存系統，用於在動態應用中減小數據庫負載，提高訪問速度。在本文主要用來實現session共享。

NFS 在本文用來實現web源程序目錄掛載到web服務器的本地目錄

1．拓撲圖

2．服務器主機名與IP分配

VIP:192.168.1.10

Virtual Server

主機名:lvs1

Eth0_IP:192.168.1.2/24

Eth1_IP:192.168.10.9/29(heartbeat line)

Virtual Server_backup

主機名:lvs2

Eth0_IP:192.168.1.3/24

Eth1_IP:192.168.10.10/29(heartbeat line)

Real Server web1

主機名:web1

IP:192.168.1.4/24

Real Server web2

主機名:web2

IP:192.168.1.5/24

Memcached and web code

主機名:share

IP:192.168.1.6/24

Mysql server

主機名：data

IP:192.168.1.7/24

2、安裝與配置LVS

1.安裝 ipvsadm

# tar zxvf ipvsadm-1.24.tar

# cd ipvsadm-1.24

# ln –s /usr/src/kernels/2.6.18-53.el5-i686/ /usr/src/linux

# make

# make install

2. Configure shell of tunlvs on Vritual Server and Vritual server_backup

# vi /etc/rc.d/init.d/tunlvs

#!/bin/sh

VIP=192.168.1.10

WEB1=192.168.1.4

WEB2=192.168.1.5

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

case "$1" in

start)

echo "start LVS directorserver"

/sbin/ifconfig tunl0 $VIP broadcast $VIP netmask 255.255.255.255 up

/sbin/route add -host $VIP dev tunl0

/sbin/ipvsadm -C

/sbin/ipvsadm -A -t $VIP:80 -s wlc

/sbin/ipvsadm -a -t $VIP:80 -r $WEB1:80 -i

/sbin/ipvsadm -a -t $VIP:80 -r $WEB2:80 -i

/sbin/ipvsadm

;;

stop)

echo "close LVS directorserver"

/sbin/ipvsadm -C

;;

*)

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

exit 1

esac

# chmod 755 /etc/rc.d/init.d/tunlvs

三、Configure shell of tunl on Real_web1 and Real_web2

# vi /etc/rc.d/init.d/tunl

#!/bin/sh

VIP=192.168.1.10

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

case "$1" in

start)

echo "tunl port starting"

/sbin/ifconfig tunl0 $VIP broadcast $VIP netmask 255.255.255.255 up

/sbin/ifconfig add -host $VIP dev tunl0

echo "1">/proc/sys/net/ipv4/conf/tunl0/arp_ignore

echo "2">/proc/sys/net/ipv4/conf/tunl0/arp_announce

echo "1">/proc/sys/net/ipv4/conf/all/arp_ignore

echo "2">/proc/sys/net/ipv4/conf/all/arp_announce

sysctl –p

;;

stop)

echo "tunl port closing"

ifconfig tunl0 down

echo "1">/proc/sys/net/ipv4/ip_forward

echo "0">/proc/sys/net/ipv4/conf/all/arp_announce

;;

*)

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

exit 1

esac

四、test lvs

Virtual Server：

# /etc/rc.d/init.d/tunlvs start

Real_web1 and Real_web2：

# /etc/rc.d/init.d/tunl start

Real_web1:

# echo 「this is test for web1」>>/var/www/html/index.html

Real_web2:

# echo 「this is test for web2」>>/var/www/html/index.html

5、NFS與Memcached(Session共享)

1．Nfs

# rpm -ivh /mnt/CentOS/portmap-4.0-65.2.2.1.i386.rpm

# rpm -ivh /mnt/CentOS/nfs-utils-1.0.9-24.el5.i386.rpm

# vi /etc/exports

/webdata 192.168.1.4(rw,sync,no_wdelay) 192.168.1.5(rw,sync,no_wdelay)

# chkconfig –level 35 portmap on

# chkconfig –level 35 nfs on

# /etc/rc.d/init.d/portmap start

# /etc/rc.d/init.d/nfs start

2.Memcached

# rpm –ivh /mnt/Centos/ libevent-1.1a-3.2.1.i386.rpm

# rpm –ivh /mnt/Centos/ libevent-devel-1.1a-3.2.1.i386.rpm

# tar zxvf memcached-1.2.6.tar.tar

# ./configure

# make && make install

# memcached -d -m 512 –l 192.168.1.6 -p 11211 -u root

# killall –HUP memcached

6、掛載 web主目錄與配置php使用session共享

Real_web1 and Real_web2

1．mount

# showmount –e 192.168.1.6

# mount –t nfs 192.168.1.6:/webdata /var/www/html

# vi /etc/fstab

192.168.1.6:/webdata /var/www/html nfs defaults 0 0

2. 配置php使用session共享

# tar zxvf memcache-2.2.3.tgz

# phpize

# ./configure –enable-memcache

# make && make install

# vi /etc/php.ini

[Session]

extension=memcache.so

extension_dir = "/usr/lib/php/modules"

session.save_handler = memcache
session.save_path = 「tcp://192.168.1.6:11211」

7、監控頁的設置

Real_web1 and Real_web2:

這裏是配合ldirectord.cf的ldirectord守護進程

# mkdir /var/www/test

# vi /etc/httpd/conf/httpd.conf

Alias /test/ "/var/www/test/"

<Directory "/var/www/test/">

    Options FollowSymLinks

    AllowOverride None

    Order allow,deny

    Allow from all

</Directory>

# echo "Test Page" > /var/www/test/test.html

8、Mysql Server

# /etc/rc.d/init.d/mysqld start

# mysqladmin -u root -p password test

# mysql –root –p

> grant all on *.* to mysql@’192.168.1.0/24’ identified by ‘your_password ’with grant option;

> flush privileges;                    

> quit;