1.准备工作
两个Linux服务器,可以用VMware装一个,然后配置好再克隆一个,修改IP即可。Host1：192.168.0.79Host2：192.168.0.80先配置好jdk1.6.0和tomcat6。Host1上还将配置Nginx(负载均衡),Terracotta(session集群).2.安装Terracotta下载Terracotta的包，http://d2zwv9pap9ylyd.cloudfront.net/terracotta-3.4.1-installer.jar 带安装功能的包http://d2zwv9pap9ylyd.cloudfront.net/terracotta-3.4.1.tar.gz 不带安装的包http://d2zwv9pap9ylyd.cloudfront.net/terracotta-3.4.1-src.tar.gz 源码包这里使用terracotta-3.4.1.tar.gztar zxvf terracotta-3.4.1.tar.gzmv terracotta-3.4.1 /usr/local/terracotta3.配置Tomcat作为Terracotta的客户端复制/usr/local/terracotta/sessions/terracotta-session-1.1.1.jar/usr/local/terracotta/common/terracotta-toolkit-1.1-runtime-2.1.0.jar这两个jar到Tomcat对应目录。Tomcat 5.0 and 5.5 对应目录 $CATALINA_HOME/server/libTomcat 6.0 对应目录 $CATALINA_HOME/lib编辑/usr/apache-tomcat-6.0.14/conf/context.xml文件<Context><!-- 增加此配置 --><Valve className="org.terracotta.session.TerracottaTomcat60xSessionValve" tcConfigUrl="localhost:9510"/></Context>如上是Tomcat6的配置方式，其他WebServer配置方式可见参考文档的具体说明。9510端口为Terracotta的通讯端口，另外默认9520为它的管理端口稍后用到。4.启动单Terracotta，测试。启动Terracotta[Host1]# /usr/local/terracotta/bin/start-tc-server.sh &启动Tomcat[Host1]# service tomcatd start[Host2]# service tomcatd start(注意：之前Host2处的Tomcat context.xml配置需要修改为<Valve className="org.terracotta.session.TerracottaTomcat60xSessionValve" tcConfigUrl="192.168.0.79:9510"/>即指向启动的Terracotta)启 动Windows下的Terracotta开发控制台(Terracotta Developer Console)，此控制台使用9520端口来监控Terracotta,这个用terracotta-3.4.1-installer.jar带安装的 软件包可以在Windows下安装或tar解压运行也可。[PROMPT] ${TERRACOTTA_HOME}\bin\dev-console.bat(注意：需要配置Linux主机名才能远程监控的到。设置主机名(如果要永久修改RedHat的hostname，就修改/etc/sysconfig/network文件，将里面的HOSTNAME这一行修改成HOSTNAME=NEWNAME)编辑/etc/hosts::1 localhost.localdomain localhost192.168.0.79 Host1 #添加此行然后service network restart，查验hostname:[root@localhost ~]# hostnamehost1)通过Terracotta Developer Console查看连接的Terracotta Server和Tomcat Client是否正常。5.安装、配置Nginx下载http://nginx.org/en/download.html安装Nginx: (预先需要安装：rpm -ivh pcre-devel-6.6-2.el5_1.7.i386.rpm)[Host1]#tar zxvf nginx-0.8.54.tar.gz[Host1]#cd nginx-0.8.54[Host1]#./configure --with-http_stub_status_module[Host1]#make;make install简单配置：修改/usr/local/nginx/conf/nginx.conf...http { ... upstream mysvr { server 192.168.0.79:8080; server 192.168.0.80:8080; } server { listen 80; server_name 192.168.0.79; location / { proxy_pass http://mysvr; .... }…
}
}
...测试配置文件/usr/local/nginx/sbin/nginx -t启动Nginx/usr/local/nginx/sbin/nginx6.观察集群sessionjsp验证页test.jsp,部署到两个Tomcat的ROOT项目下:<%@ page session="true" %><html><head> <title>test Host1</title> <!-- //Host2就写为"test Host1" 以示区分 --></head><body><% out.println("Session Id:"+request.getSession().getId()+"<br />"); out.println("Creation Time:"+request.getSession().getCreationTime()); String name=(String)session.getAttribute("name"); if(name==null||name.equals("")){ session.setAttribute("name","Hello Host1!"); //Host2就写为"Hello Host2!" out.println(session.getAttribute("name")); }else{ out.println(name); }%></body></html>
访问test.jsphttp://192.168.0.79/test.jsp刷新多次。发现除session的id号被Terracotta加了个类似版本编号的后缀有所区别,例如：Session Id:2jUFdCvDTqrZViJXzvh8.3和Session Id:2jUFdCvDTqrZViJXzvh8.2,以外其他的输出都是一致的。已达到session集群的作用。如 果关闭Terracotta，然后注释/usr/apache-tomcat-6.0.14/conf/context.xml文件的Valve,重启两 个tomcat，再次访问，并刷新，会发现sessionid及其内容在跳变，没有集群特性。这就是Terracotta的作用。另外有两个单点故障的点，Nginx和Terracotta，Nginx可以通过keepalived配置为热备;Terracotta内置了热备方式，可以在Host2上也启用Terracotta，需要tc-config.xml配置，具体可参见官方文档。参考文档：http://www.terracotta.org/documentation/product-documentation-1page.html 5 Clustering Web Applications with Terracotta Web Sessions 章节------------------------------------------------------------------------------------------------------------------------------------------------------配置Terracotta双机热备。[Host1]#/bin/start-tc-server.sh -f /usr/local/terracotta/tc-config.xml -n Server1 &[Host2]#/bin/start-tc-server.sh -f /usr/local/terracotta/tc-config.xml -n Server2 &tc-config.xml 样例：<?xml version="1.0" encoding="UTF-8"?><!-- All content copyright Terracotta, Inc., unless otherwise indicated. All rights reserved. --><tc:tc-config xsi:schemaLocation="http://www.terracotta.org/schema/terracotta-5.xsd"xmlns:tc="http://www.terracotta.org/config"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <servers> <!-- Sets where the Terracotta server can be found. Replace the value of host with the server's IP address. --> <server host="192.168.0.79" name="Server1"> <data>%(user.home)/terracotta/server-data</data> <logs>%(user.home)/terracotta/server-logs</logs> </server> <!-- If using a standby Terracotta server, also referred to as an ACTIVE-PASSIVE configuration, add the second server here. --> <server host="192.168.0.80" name="Server2"> <data>%(user.home)/terracotta/server-data</data> <logs>%(user.home)/terracotta/server-logs</logs> </server><!-- If using more than one server, add an <ha> section. --> <ha> <mode>networked-active-passive</mode> <networked-active-passive> <election-time>5</election-time> </networked-active-passive> </ha> </servers> <!-- Sets where the generated client logs are saved on clients. --> <clients> <logs>%(user.home)/terracotta/client-logs</logs> </clients></tc:tc-config>