Question

The following document says:

This is easier to do and does not require a sysadmin. However, it is not the preferred approach for production systems for the reasons listed above. This approach is usually used in development to try out clustering behavior.

What are risks with this approach in the production environment? In weblogic, it is pretty common, and seen few production environments running with multiple ports(managed servers).

https://community.jboss.org/wiki/ConfiguringMultipleJBossInstancesOnOnemachine

Answer 1

The wiki clearly answers that question. Here is the text from the wiki for your reference

Where possible, it is advised to use a different ip address for each instance of JBoss rather than changing the ports or using the Service Binding Manager for the following reasons:

1. When you have a port conflict, it makes it very difficult to troubleshoot, given a large amount of ports and app servers.
2. Too many ports makes firewall rules too difficult to maintain.
3. Isolating the IP addresses gives you a guarantee that no other app server will be using the ports.
4. Each upgrade requires that you go in and re set the binding manager again. Most upgrades will upgrade the conf/jboss-service.xml file, which has the Service binding manager configuration in it.
5. The configuration is much simpler. When defining new ports(either through the Service Binding manager or by going in and changing all the ports in the configuration), it’s always a headache trying to figure out which ports aren’t taken already. If you use a NIC per JBoss Instance, all you have to change is the Ip address binding argument when executing the run.sh or run.bat. (-b )
6. Once you get 3 or 4 applications using different ports, the chances really increase that you will step on another one of your applications ports. It just gets more difficult to keep ports from conflicting.
7. JGroups will pick random ports within a cluster to communicate. Sometimes when clustering, if you are using the same ip address, two random ports may get picked in two different app servers(using the binding manager) that conflict. You can configure around this, but it’s better not to run into this situation at all.
   On a whole, having an individual IP addresses for each instance of an app server causes fewer problems (some of those problems are mentioned here, some aren’t).