centos環境中tomcat如何進行集群部署

在CentOS環境中進行Tomcat集群部署，通常涉及以下幾個步驟：

1. 準備環境

確保所有服務器上都安裝了Java和Tomcat。

安裝Java

sudo yum install java-1.8.0-openjdk-devel

安裝Tomcat

可以從Tomcat官網下載最新版本的Tomcat，并解壓到指定目錄。

wget https://archive.apache.org/dist/tomcat/tomcat-9/v9.0.56/bin/apache-tomcat-9.0.56.tar.gz
tar -zxvf apache-tomcat-9.0.56.tar.gz -C /opt/
ln -s /opt/apache-tomcat-9.0.56 /opt/tomcat

2. 配置Tomcat集群

2.1 配置server.xml

在每個Tomcat實例的conf/server.xml文件中配置集群相關的參數。

Server1:

<Server port="8005" shutdown="SHUTDOWN">
  <Listener className="org.apache.catalina.ha.tcp.SimpleTcpClusterListener" />
  <Listener className="org.apache.catalina.ha.session.JvmRouteBinderListener" />
  <Listener className="org.apache.catalina.ha.session.ClusterSessionListener" />

  <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>
</Server>

Server2:

<Server port="8006" shutdown="SHUTDOWN">
  <Listener className="org.apache.catalina.ha.tcp.SimpleTcpClusterListener" />
  <Listener className="org.apache.catalina.ha.session.JvmRouteBinderListener" />
  <Listener className="org.apache.catalina.ha.session.ClusterSessionListener" />

  <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="4001"
                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>
</Server>

2.2 配置context.xml

在每個Tomcat實例的conf/context.xml文件中添加集群相關的配置。

<Context>
  <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>
</Context>

3. 啟動Tomcat

在每個服務器上啟動Tomcat。

/opt/tomcat/bin/startup.sh

4. 驗證集群

訪問任意一個Tomcat實例的URL，例如http://server1_ip:8080，然后訪問另一個實例的URL，例如http://server2_ip:8080，確保兩個實例都能正常訪問并且會話是共享的。

5. 配置負載均衡器（可選）

可以使用Nginx或Apache作為負載均衡器來分發請求到不同的Tomcat實例。

使用Nginx配置負載均衡

http {
    upstream tomcat_cluster {
        server server1_ip:8080;
        server server2_ip:8080;
    }

    server {
        listen 80;

        location / {
            proxy_pass http://tomcat_cluster;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
        }
    }
}

通過以上步驟，你可以在CentOS環境中成功部署一個Tomcat集群。