To demonstrate Tomcat 9 clustering on a Windows 10/11 machine with Tomcat 9 installed and launched from within Eclipse, you can follow the official documentation provided in the “Clustering/Session Replication How-To” guide. Here’s a step-by-step guide based on this document for our set up:

1. Prepare Your Environment:

   -  Ensure you have Tomcat 9 installed on your Windows 10/11 machine.
      	
   -  Have Eclipse IDE installed and configured.
   

2. Edit Tomcat Server Configuration:

   • Open your Tomcat server configuration in Eclipse.

- Locate the server.xml file within your Tomcat installation directory (usually under <Tomcat_Home>/conf).

1. Enable Clustering:

   • In the server.xml file, find the <Engine> or <Host> element where you want to enable clustering.
   • Add the following line inside the selected element to enable clustering:

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

   • This configuration enables all-to-all session replication using the DeltaManager.

2. Adjust Configuration (Optional):

   • You can modify the cluster configuration as needed based on your requirements. Refer to the documentation for more advanced configurations.

3. Start Tomcat Servers:

   • Start two instances of Tomcat (e.g., TomcatA and TomcatB) from Eclipse. Ensure they run on different ports and have unique names.

4. Test Session Replication:

   • Create a simple web application in Eclipse.
   • In your web.xml, ensure you have the <distributable/> element to mark the web application as distributable.

5. Deploy and Access the Web Application:

   - Deploy your web application to both TomcatA and TomcatB.
   - Access your web application in a web browser.
   

6. Simulate Failover:

   • To demonstrate session replication and failover, perform actions that create sessions (e.g., login, set session attributes) on one Tomcat instance (TomcatA).
   • Stop TomcatA abruptly to simulate a crash.
7. Observe Failover:
   • Access your web application again after TomcatA has crashed.
   • You should see that session data is maintained, demonstrating successful failover to TomcatB.
8. Additional Testing (Optional):
   • Explore more scenarios mentioned in the documentation, such as session invalidation, and observe how clustering handles them.
9. Monitoring (Optional):
   • You can monitor your cluster using JMX. Follow the instructions in the documentation to enable JMX monitoring.
10. FAQ and Troubleshooting (Optional):
    • Refer to the FAQ section in the documentation for answers to common questions and troubleshooting tips.

This step-by-step guide should help you better understand Tomcat 9 clustering when using Windows 10/11 and Eclipse.