Tomcat Session ID---会话保持

简单拓补图

一、负载均衡、反向代理

7-1nginx代理服务器配置

[root@dlnginx ~]#yum  install epel-release.noarch -y  ###安装额外源

[root@dlnginx ~]#yum install nginx -y

[root@dlnginx ~]#systemctl start  nginx.service

[root@dlnginx ~]#systemctl status  nginx.service

[root@dlnginx ~]#vim /etc/nginx/nginx.conf          ###主配置文件

upstream tomcat {
    server 192.168.10.101:8080;
    server 192.168.10.102:8080;
    }


location ~* \.jsp$ {
        proxy_pass http://tomcat;
        }

7-2和7-3同时进行配置

[root@Tomcat1 ~]#cd /data/

上传

[root@Tomcat1 data]#ls
apache-tomcat-9.0.16.tar(1).gz  jdk-8u291-linux-x64.tar(1).gz

[root@Tomcat1 data]#tar xf jdk-8u291-linux-x64.tar\(1\).gz  -C /usr/local/

[root@Tomcat1 data]#ls /usr/local/
bin  etc  games  include  jdk1.8.0_291  lib  lib64  libexec  sbin  share  src

[root@Tomcat1 data]#cd /usr/local/

[root@Tomcat1 local]#ls
bin  etc  games  include  jdk1.8.0_291  lib  lib64  libexec  sbin  share  src

[root@Tomcat1 local]#ln -s jdk1.8.0_291/ jdk

[root@Tomcat1 local]#ls
bin  etc  games  include  jdk  jdk1.8.0_291  lib  lib64  libexec  sbin  share  src

[root@Tomcat1 local]#vim /etc/profile.d/env.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@Tomcat1 local]#. /etc/profile.d/env.sh 

[root@Tomcat1 local]#java -version

[root@Tomcat1 data]#tar xf apache-tomcat-9.0.16.tar\(1\).gz -C /usr/local/
[root@Tomcat1 data]#cd /usr/local/
[root@Tomcat1 local]#ls
apache-tomcat-9.0.16  bin  etc  games  include  jdk  jdk1.8.0_291  lib  lib64  libexec  sbin  share  src
[root@Tomcat1 local]#ln -s apache-tomcat-9.0.16/ tomcat
[root@Tomcat1 local]#ls
apache-tomcat-9.0.16  bin  etc  games  include  jdk  jdk1.8.0_291  lib  lib64  libexec  sbin  share  src  tomcat
[root@Tomcat1 local]#useradd -s /sbin/nologin tomcat
[root@Tomcat1 local]#chown tomcat:tomcat tomcat/ -R
[root@Tomcat2 local]#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.target
> 
> EOF

[root@Tomcat2 local]#systemctl daemon-reload
[root@Tomcat2 local]#systemctl start tomcat.service 
[root@Tomcat2 local]#ss -ntap |grep 8080
LISTEN     0      100         :::8080                    :::*                   users:(("java",pid=2767,fd=54))
[root@Tomcat2 local]#systemctl status tomcat.service

进入主页面进行配置

检测：

去访问代理服务器会发现，每次调度到192.168.246.8和192.168.246.9上面，sessionID都会改变，我们要让他保持会话连接(sessionID不会变)

客户端访问代理服务器，第一次访问被调度到tomcat1服务器，由于是第一次访问，客户的cookie缓存中不会有sessionid,服务器会生成sessionid 1给 c1客户，c1客户会把sessionid  记录下来

客户端第二次访问代理服务器，由于调度器的原因，不能保证一直去访问tomcat1，如果被调度到tomcat2, tomcat2服务器是没有sessionid 1， 它会认为我要生成新的sessionid 给c1客户，c1客户会更新自己的sessionid变成sessionid2


1.当客户端去访问代理服务器；代理服务器调度给Tomcat1；如果是第一次访问：客户端cookie里面没有sessionID，Tomcat1服务器就给给客户端生成一个sessionID并且发给客户端；客户端会将sessionID存在cookie中；当客户端第二次去访问Tomcat1时，会带着Tomcat1的sessionID，第二次，Tomcat1就不会给客户端生成新的sessionID

2.由于代理服务器调度的原因；不会每次都调度给Tomcat1；当调度给Tomcat2时；cookie带的是sessionID1；Tomcat2上要用sessionID2，他就会生成一个新的ID给客户端

3.所以，来回调度的时候，每次都是新的sessionID

二、会话保持

方法一：

检验：访问代理服务器

session id固定了，但是服务器也固定了不调度了

方法二：

Apache Tomcat 9 (9.0.87) - Clustering/Session Replication How-To

<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="auto"
                      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>