目录
前言
一、部署环境
二、部署nginx反向代理服务器
三、部署tomcat服务器1
四、部署tomcat服务器2
五、客户端测试（Session ID不断变动）
六、配置Session ID会话保持
七、客户端测试（Session ID保持）
前言
此次实验是Tomcat后端服务器如何做Session ID会话保持
一、部署环境
关闭所有设备的防火墙和核心防护
[root@localhost ~]#systemctl stop firewalld
[root@localhost ~]#setenforce 0安装设备对应的服务软件，如nginx反向代理服务器安装nginx软件，Tomcat服务器1和2需安装tomcat软件
#nginx反向代理服务器
[root@localhost ~]#yum install epel-release.noarch -y
[root@localhost ~]#yum install -y nginx
[root@localhost ~]#systemctl start nginx#Tomcat服务器1和2需安装tomcat软件
#安装jdk工具，事先准备好oraclejdk二进制包 [root@localhost ~]#cd /opt [root@localhost opt]#rz -E rz waiting to receive. [root@localhost opt]#ls jdk-8u291-linux-x64.tar.gz [root@localhost opt]#tar xf jdk-8u291-linux-x64.tar.gz -C /usr/local/ [root@localhost opt]#cd /usr/local [root@localhost local]#ls bin etc games include jdk1.8.0_291 lib lib64 libexec sbin share src [root@localhost local]#ln -s jdk1.8.0_291/ jdk [root@localhost local]#vim /etc/profile.d/jdk.sh export JAVA_HOME=/usr/local/jdk export PATH=$JAVA_HOME/bin:$PATH export JRE_HOME=$JAVA_HOME/jre export CLASSPATH=$JAVA_HOME/lib/:$JRE_HOME/lib/ [root@localhost local]#. /etc/profile.d/jdk.sh [root@localhost local]#java -version java version "1.8.0_291" Java(TM) SE Runtime Environment (build 1.8.0_291-b10) Java HotSpot(TM) 64-Bit Server VM (build 25.291-b10, mixed mode)#安装tomcat，事先准备好tomcat二进制安装包 [root@localhost local]#cd /opt [root@localhost opt]#rz -E rz waiting to receive. [root@localhost opt]#tar xf apache-tomcat-9.0.16.tar.gz [root@localhost opt]#cp -r /opt/apache-tomcat-9.0.16 /usr/local/tomcat [root@localhost opt]#useradd -M -s /sbin/nologin tomcat [root@localhost opt]#chown -R tomcat:tomcat /usr/local/tomcat/ [root@localhost opt]#cat > /usr/lib/systemd/system/tomcat.service <<EOF [Unit] Description=Tomcat After=syslog.target network.target[Service] Type=forking ExecStart=/usr/local/tomcat/bin/startup.sh ExecStop=/usr/local/tomcat/bin/shutdown.sh RestartSec=3 PrivateTmp=true User=tomcat Group=tomcat[Install] WantedBy=multi-user.targetEOF [root@localhost opt]#systemctl daemon-reload [root@localhost opt]#systemctl start tomcat.service
二、部署nginx反向代理服务器
[root@localhost ~]#vim /etc/nginx/nginx.conf
upstream tomcat {server 172.16.12.11:8080;server 172.16.12.12:8080;}location ~* \.jsp$ {proxy_pass http://tomcat;}
[root@localhost ~]#nginx -t
[root@localhost ~]#systemctl restart nginx
三、部署tomcat服务器1
[root@localhost ~]#cd /usr/local/tomcat/webapps/ROOT/
[root@localhost ROOT]#mv index.jsp index.jsp.bak
[root@localhost ROOT]#cat > index.jsp << EOF
<%@ page import="java.util.*" %>
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>tomcat test</title>
</head>
<body>
<div>On <%=request.getServerName() %></div>
<div><%=request.getLocalAddr() + ":" + request.getLocalPort() %></div>
<div>SessionID = <span style="color:blue"><%=session.getId() %></span></div>
<%=new Date()%>
</body>
</html>
EOF
[root@localhost ROOT]#systemctl restart tomcat.service
四、部署tomcat服务器2
[root@localhost opt]#cd /usr/local/tomcat/webapps/ROOT/
[root@localhost ROOT]#mv index.jsp index.jsp.bak
[root@localhost ROOT]#cat > index.jsp << EOF
<%@ page import="java.util.*" %>
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>tomcat test</title>
</head>
<body>
<div>On <%=request.getServerName() %></div>
<div><%=request.getLocalAddr() + ":" + request.getLocalPort() %></div>
<div>SessionID = <span style="color:blue"><%=session.getId() %></span></div>
<%=new Date()%>
</body>
</html>
EOF
[root@localhost ROOT]#systemctl restart tomcat.service
五、客户端测试（Session ID不断变动）
客户端访问：http://nginx反向代理服务器IP地址/index.jsp
在实际环境中，不允许用户的Session ID不断变化
- 当客户端第一次访问nginx反向代理服务器，nginx反向代理服务器会通过轮询的算法，调度到Tomcat服务器1上处理，由于是第一次访问，客户度的Cookie缓存会记录，不会有Session ID，Tomcat服务器1会生成新的Session ID传输给客户端，客户端会将这个新的Session ID记录下来
- 当客户端第二次访问的时候，Nginx反向代理服务器又可能通过轮询的算法，将服务请求调度到Tomcat服务器2上处理，Tomcat服务器2是没有客户端传输来的Session ID1的，Tomcat2服务器认为客户端要生成新的Session ID，于是Tomcat2服务器将新的Session ID2传输给客户端，客户端会更新Session ID，将刚刚的Session ID1更改为Session ID2；
- 当客户端第三次访问的时候，客户端带着Session ID2去Nginx代理服务器，Nginx反向代理服务器将客户端请求又调度到Tomcat服务器1上，Tomcat服务器1并没有Session ID2，于是又将新生成的Session ID3传输给客户端，这样会有很不好的客户端体验，所以我们可以根据修改Tomcat配置文件来进行会话保持
六、配置Session ID会话保持
Tomcat会话保持官方说明：https://tomcat.apache.org/tomcat-9.0-doc/cluster-howto.htmltomcat服务器1配置：
[root@node2 ROOT]#vim /usr/local/tomcat/conf/server.xml
<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"channelSendOptions="8"><Manager className="org.apache.catalina.ha.session.DeltaManager"expireSessionsOnShutdown="false"notifyListenersOnReplication="true"/><Channel className="org.apache.catalina.tribes.group.GroupChannel"><Membership className="org.apache.catalina.tribes.membership.McastService"address="228.0.0.4"port="45564"frequency="500"dropTime="3000"/><Receiver className="org.apache.catalina.tribes.transport.nio.NioReceiver"address="172.16.12.11"port="4000"autoBind="100"selectorTimeout="5000"maxThreads="6"/><Sender className="org.apache.catalina.tribes.transport.ReplicationTransmitter"><Transport className="org.apache.catalina.tribes.transport.nio.PooledParallelSender"/></Sender><Interceptor className="org.apache.catalina.tribes.group.interceptors.TcpFailureDetector"/><Interceptor className="org.apache.catalina.tribes.group.interceptors.MessageDispatchInterceptor"/></Channel><Valve className="org.apache.catalina.ha.tcp.ReplicationValve"filter=""/><Valve className="org.apache.catalina.ha.session.JvmRouteBinderValve"/><Deployer className="org.apache.catalina.ha.deploy.FarmWarDeployer"tempDir="/tmp/war-temp/"deployDir="/tmp/war-deploy/"watchDir="/tmp/war-listen/"watchEnabled="false"/><ClusterListener className="org.apache.catalina.ha.session.ClusterSessionListener"/></Cluster>
[root@localhost ROOT]#vim /usr/local/tomcat/webapps/ROOT/WEB-INF/web.xml
<distributable/>
[root@localhost ROOT]#systemctl restart tomcat.service
[root@localhost ROOT]#systemctl status tomcat.service
tomcat服务器2配置：
[root@localhost ROOT]#scp /usr/local/tomcat/conf/server.xml 172.16.12.12:/opt
[root@localhost ROOT]#scp /usr/local/tomcat/webapps/ROOT/WEB-INF/web.xml 172.16.12.12:/opt
[root@localhost ROOT]#cd /opt
[root@localhost opt]#cp server.xml /usr/local/tomcat/conf/server.xml
cp：是否覆盖"/usr/local/tomcat/conf/server.xml"？ y
[root@localhost opt]#cp web.xml /usr/local/tomcat/webapps/ROOT/WEB-INF/web.xml
cp：是否覆盖"/usr/local/tomcat/webapps/ROOT/WEB-INF/web.xml"？ y
[root@localhost opt]#vim /usr/local/tomcat/webapps/ROOT/WEB-INF/web.xml
修改IP地址（tomcat服务器2的IP）
[root@localhost opt]#systemctl restart tomcat.service
[root@localhost opt]#systemctl status tomcat.service
七、客户端测试（Session ID保持）
客户端访问：http://nginx反向代理服务器IP地址/index.jsp
