此類話題已經(jīng)很多，可以參考的文檔也不少，我是參考這個blog的文檔做的：
http://blogger.org.cn/blog/blog.asp?name=lhwork
1）環(huán)境和版本：
Apache2.0.59+Tomcat5.5.15（兩個），一開始用的是Tomcat5.0.28，一直有問題（在后面總結(jié)），就升級到5.5去做試驗了，冤枉5.0.28兄弟了:)
步驟小結(jié)為：
1、安裝（忽略）；
2、配置Tomcat：
???1）第一個Tomcat：
??????A.啟用jvmRoute??????
??? <!-- You should set jvmRoute to support load-balancing via AJP ie :-->
??? <Engine name="Standalone" defaultHost="localhost" jvmRoute="tomcat1">??????????
??? <!-- Define the top level container in our container hierarchy
??? <Engine name="Catalina" defaultHost="localhost">-->
??????B.啟用原來禁用的Cluster設(shè)置
??????
??????? <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"
????????????????mcastBindAddress="127.0.0.1"
??????????????? mcastAddr="224.1.2.3"
??????????????? mcastPort="2525"
??????????????? mcastFrequency="500"
??????????????? mcastDropTime="3000"/>
??????????? <Receiver
??????????????? className="org.apache.catalina.cluster.tcp.ReplicationListener"
??????????????? tcpListenAddress="auto"
??????????????? tcpListenPort="4001"
??????????????? tcpSelectorTimeout="100"
??????????????? tcpThreadCount="6"/>
??????????? <Sender
??????????????? className="org.apache.catalina.cluster.tcp.ReplicationTransmitter"
??????????????? replicationMode="pooled"
??????????????? ackTimeout="15000"/>
??????????? <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"/>
?????????????????????
??????????? <ClusterListener className="org.apache.catalina.cluster.session.ClusterSessionListener"/>
??????? </Cluster>
??????C.搞定
???2）配置第二個Tomcat（要注意端口沖突了）：
??????A.變更端口
??????<Server port="8005" shutdown="SHUTDOWN">
??????＝》
??????<Server port="8004" shutdown="SHUTDOWN">
??????B.變更端口
??????<Connector port="8009"
?????????????? enableLookups="false" redirectPort="8443" protocol="AJP/1.3" />
??????＝》
??????<Connector port="9009"
?????????????? enableLookups="false" redirectPort="8443" protocol="AJP/1.3" />
??????C.啟用jvmRoute??????
??? <!-- You should set jvmRoute to support load-balancing via AJP ie :-->
??? <Engine name="Standalone" defaultHost="localhost" jvmRoute="tomcat2">??????????
??? <!-- Define the top level container in our container hierarchy
??? <Engine name="Catalina" defaultHost="localhost">-->
??????D.啟用原來禁用的Cluster設(shè)置??????
??????? <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"
????????????????mcastBindAddress="127.0.0.1"
??????????????? mcastAddr="224.1.2.3"
??????????????? mcastPort="2525"
??????????????? mcastFrequency="500"
??????????????? mcastDropTime="3000"/>
??????????? <Receiver
??????????????? className="org.apache.catalina.cluster.tcp.ReplicationListener"
??????????????? tcpListenAddress="auto"
??????????????? tcpListenPort="4002"
??????????????? tcpSelectorTimeout="100"
??????????????? tcpThreadCount="6"/>
??????????? <Sender
??????????????? className="org.apache.catalina.cluster.tcp.ReplicationTransmitter"
??????????????? replicationMode="pooled"
??????????????? ackTimeout="15000"/>
??????????? <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"/>
?????????????????????
??????????? <ClusterListener className="org.apache.catalina.cluster.session.ClusterSessionListener"/>
??????? </Cluster>
??????E.搞定
3、配置apache：
???1）修訂conf/httpd.conf??????
??????#add by zhengxq
??????LoadModule jk2_module modules/mod_jk2.so
???2）新增worders2.properties并放到conf下
??????[shm]
info=Scoreboard. Requried for reconfiguration and status with multiprocess servers.
file=anon
# Defines a load balancer named lb. Use even if you only have one machine.
[lb:lb]
worker=ajp13:tomcat1
worker=ajp13:tomcat2
# Example socket channel, override port and host.
[channel.socket:localhost:9009]
port=9009
host=127.0.0.1
# define the worker
[ajp13:localhost:9009]
channel=channel.socket:localhost:9009
group=lb
# Example socket channel, override port and host.
[channel.socket:localhost:8009]
port=8009
host=127.0.0.1
# define the worker
[ajp13:localhost:8009]
channel=channel.socket:localhost:8009
group=lb
# Map the Tomcat examples webapp to the Web server uri space
[uri:/clusterapp/*]
group=lb
??????3）搞定
3.測試程序，請參考上述參考文檔，如下：
<%@ page contentType="text/html; charset=GBK" import="java.util.*"%>
<html><head><title>Cluster App Test</title></head>
<body>
Server Info: <%out.print(request.getLocalAddr() + " : " + request.getLocalPort());%>
<%
out.println("<br> ID " + session.getId());
// 如果有新的 Session 屬性設(shè)置
String dataName = request.getParameter("dataName");
if (dataName != null && dataName.length() > 0) {
? String dataValue = request.getParameter("dataValue");
? session.setAttribute(dataName, dataValue);
}
out.print("<b>Session 列表</b>");
Enumeration e = session.getAttributeNames();
while (e.hasMoreElements()) {
? String name = (String)e.nextElement();
? String value = session.getAttribute(name).toString();
? out.println( name + " = " + value);
? }
%>
<form action="index.jsp" method="POST">
? 名稱:<input type=text size=20 name="dataName">
? <br>
? 值:<input type=text size=20 name="dataValue">
? <br>
? <input type=submit>
? </form>
</body>
</html>
???所需要注意的是：
???1、測試應(yīng)用的web.xml必須加上：<distributable/>
???2、我搞了很久，發(fā)現(xiàn)三個東西起來后，可以訪問，但只能做到負載均衡，不能session復(fù)制，這點我重復(fù)配置了一次，就是不行，郁悶之下找了tomcat的郵件列表，這樣做：
??????1）測試廣播是否正常
?????????A. download this jar
????????????http://cvs.apache.org/~fhanik/tomcat-replication.jar
?????????B. Open two terminals?
??????????? a) Terminal one run
???????????????java -cp tomcat-replication.jar MCaster 239.255.10.10 2525 Terminal1
??????????? b) Terminal two run
???????????????java -cp tomcat-replication.jar MCaster 239.255.10.10 2525 Terminal2
?????????發(fā)現(xiàn)結(jié)果如下：
?????????C:\>java -cp tomcat-replication.jar MCaster 224.1.2.3 2525 Terminal1
Usage MCaster [address port message]
BEGIN TO RECEIVE
SENT:Terminal11
SENT:Terminal12
SENT:Terminal13
SENT:Terminal14
SENT:Terminal15
SENT:Terminal16
SENT:Terminal17
SENT:Terminal18
?????????表明廣播有問題，氣死了，難怪Tomcat總是在啟動的時候提示：
?????????信息: Manager [/clusterapp]: skipping state transfer. No members active in cluster group.
??????后來終于發(fā)現(xiàn)貓膩，必須注意在server.xml的<Cluster ..<Membership里面加上mcastBindAddress="127.0.0.1"。
???????為什么呢？很簡單，因為我安裝了VPN，這家伙會設(shè)置一個虛擬網(wǎng)卡，導(dǎo)致綁定失敗（沒地方責(zé)怪了，只好讓它墊背）？！這是通過郵件列表里面所描述的多網(wǎng)卡綁定問題舉一反三得到的判斷。具體請參考：http://www.servlets.com/archive/servlet/ReadMsg?msgId=475067&listName=tomcat-user
??????