17 Dec 2009
如何做Tomcat集群和session复制？

CentOS release 5.2 (Final)

# yum –disablerepo=* –enablerepo=c5-media install httpd

# yum –disablerepo=* –enablerepo=c5-media install tomcat*

注意yum安装的顺序

# vim /etc/tomcat5/tomcat-users.xml

<user username=”ad” password=”123″ roles=”admin,manager”/>

修改后可测试管理界面

wget http://archive.apache.org/dist/tomcat/tomcat-connectors/jk/source/tomcat-connectors-1.2.28-src.tar.gz #作用是无缝拼接apache与tomcat

#tar zxvf tomcat-connectors-1.2.28-src.tar.gz

# cat BUILD.txt

# pwd

/tmp/tomcat-connectors-1.2.28-src/native

# ./configure –with-apxs=/usr/sbin/apxs

# make && make install

# cd apache-2.0/

# apxs -i -n mod_jk mod_jk.so

# cd ../../conf/

# cp workers.properties.minimal /etc/httpd/conf/workers.properties #配置如何工作

# vim /etc/httpd/conf.d/jk.conf

# Load mod_jk module

LoadModule jk_module modules/mod_jk.so

# Where to find workers.properties

JkWorkersFile conf/workers.properties

# Where to put jk shared memory

JkShmFile logs/httpd/mod_jk.shm

# Where to put jk logs

JkLogFile logs/mod_jk.log

# Set the jk log level [debug/error/info]

JkLogLevel info

# Select the log format

JkLogStampFormat “[%a %b %d %H:%M:%S %Y] ”

# JkOptions indicate to send SSL KEY SIZE,

JkOptions +ForwardKeySize +ForwardURICompat -ForwardDirectories

# JkRequestLogFormat set the request format

JkRequestLogFormat “%w %V %T %R”

# All requests go to Tomcat by default

JkMount /*.jsp wlb

JkMount /manager/* wlb

此时重启服务并打开localhost/index.jsp ，有内容则表示上一步成功。需要多少节点可根据需要在不同服务器重复上面操作。

如果上面没问题则可继续配置负载均衡集群

根据官方手册，集群前需先有一router机，所以先来配它

# vim /etc/httpd/conf/workers.properties

# The advanced router LB worker

worker.list=router,jkstatus

# Define a ‘jkstatus’ worker using status

worker.jkstatus.type=status

# Define a worker using ajp13

worker.worker1.port=8009

worker.worker1.host=node1.domain.org

worker.worker1.type=ajp13

worker.worker1.lbfactor=1

# Define preferred failover node for worker1

#worker.worker1.redirect=worker2

# Define another worker using ajp13

worker.worker2.port=8009

worker.worker2.host=node2.domain.org

worker.worker2.type=ajp13

worker.worker2.lbfactor=1

# Disable worker2 for all requests except failover

#worker.worker2.activation=disabled

# Define the LB worker

worker.router.type=lb

worker.router.balance_workers=worker1,worker2

worker.router.sticky_session=1

重启router机访问jkstatus则可看到效果，截图如下

如果上一步没有问题，那么恭喜你，负载均衡集群已经实现了。现在来完成session复制，当然下面配置要在节点中完成

# vim /etc/tomcat5/server.xml

注释：

<Engine name=”Catalina” defaultHost=”localhost”>

添加：

<Engine name=”Standalone” defaultHost=”localhost” jvmRoute=”节点主机名，如node1.domain.org”>

取消以下字段的注释令Cluster配置生效

<Cluster className=”org.apache.catalina.cluster.tcp.SimpleTcpCluster”

managerClassName=”org.apache.catalina.cluster.session.DeltaManager”

expireSessionsOnShutdown=”false”

useDirtyFlag=”true”

notifyListenersOnReplication=”true”>

<Membership

className=”org.apache.catalina.cluster.mcast.McastService”

mcastAddr=”228.0.0.4″ 组播地址

mcastPort=”45564″ 组播端口

mcastFrequency=”500″

mcastDropTime=”3000″/>

<Receiver 指定网卡如何接收session信息

className=”org.apache.catalina.cluster.tcp.ReplicationListener”

tcpListenAddress=”网卡IP”

tcpListenPort=”4001″

tcpSelectorTimeout=”100″

tcpThreadCount=”6″/>

<Sender

className=”org.apache.catalina.cluster.tcp.ReplicationTransmitter”

replicationMode=”pooled”

ackTimeout=”15000″

waitForAck=”true”/>

<Valve className=”org.apache.catalina.cluster.tcp.ReplicationValve”

filter=”.*.gif;.*.js;.*.jpg;.*.png;.*.htm;.*.html;.*.css;.*.txt;”/>

<Deployer className=”org.apache.catalina.cluster.deploy.FarmWarDeployer”

tempDir=”/tmp/war-temp/”

deployDir=”/tmp/war-deploy/”

watchDir=”/tmp/war-listen/”

watchEnabled=”false”/>

</Cluster>

这么长的一段配置看起来确实很恐怖，但是呢需要改的就几处而已，莫慌

接下来为使组播方式生效，增加路由项目

#ip ro add 228.0.0.4 dev eth0

重启tomcat，之后验证下tomcat工作是否正常，组播是否正常？

# tcpdump -i eth0 not port 22

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode

listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes

16:02:47.252607 IP node1.domain.org.45564 > 228.0.0.4.45564: UDP, length 57

16:02:47.756454 IP node1.domain.org.45564 > 228.0.0.4.45564: UDP, length 57

16:02:48.257428 IP node1.domain.org.45564 > 228.0.0.4.45564: UDP, length 57

16:02:48.759068 IP node1.domain.org.45564 > 228.0.0.4.45564: UDP, length 57

在webapps 下新建test 目录

进入test目录下建WEB-INF目录下的web.xml文件，为了防止格式被破坏其代码在

http://docs.google.com/Doc?docid=0Ae1ODIVF3AfNZGRyaGtmam5fMTUwZDdoOGhxY3A&hl=en

再在webapps 下建立session.jsp

session.jsp的代码也在上面的链接中

此时进入网页手动写一个session，然后关掉当前正在访问节点的tomcat服务并刷新网页，此时session未变。

http://192.168.56.103/test/session.jsp

至此session复制完成。

如有任何疑问在本页面留言即可。

参考文章

http://bbs.linuxtone.org/viewthread.php?tid=1195&highlight=tomcat

http://blind.javaeye.com/blog/527921

17 Dec 2009 如何做Tomcat集群和session复制？

17 Dec 2009
如何做Tomcat集群和session复制？