Terracotta Geronimo Plugin
Terracotta already has [Geronimo/WebsphereCE support], but we want to create a Geronimo plugin to make it even easier to use Terracotta with Geronimo.
This project is currently in development.
Functionality
Here's a stab at what the plugin (or set of plugins) could do, although we might want to start with just the bare minimum:
- Acquire the Terracotta bits. Here's a suggestion from Jeff Genender:
The plugin will require the Terracotta file infrastructure go under our $GERONIMO_HOME/var directory - perhaps $GERONIMO_HOME/var/terracotta. So the way we have handled this before is to place this infrastructure in the META-INF of a jar and have some magic code extract it out to the var directory. I think there are several ways to skin this cat...and I would like input from others.
- Configure a set of installed web applications to be clustered with Terracotta.
- Provide an interface for configuring Terracotta:
- Configure a set of installed web applications to be clustered with Terracotta
- More advanced config tooling
- Integrate the automated config generator stuff that Gary Keim is working on.
- Provide a Terracotta control panel inside the Geronimo admin console that lets you start and stop the Terracotta server. Could also be used to launch/view the Terracotta admin console functionality.
Issues
In order to package Terracotta up as a Geronimo plugin, a number of issues need to be resolved.
Terracotta Dependency Acquisition
This is a fancy way of saying that the Terracotta bits need to be rearranged in a way that makes it easy to bundle up. That effort is currently underway and, as of this writing, is slated for the Ortega release (Terracotta 2.5).
Starting Geronimo with Terracotta JVM Arguments
Terracotta requires the JVM to be started with certain JVM arguments. The plugin acquisition or installation process will have to include starting the Geronimo JVM with these arguments. Ideally, this would be a transparent automated process that happens as part of the plugin deployment, but it may need to be manual.
Another suggestion from Jeff G:
The plugin will need to alter the starup.sh/bat scripts in the $GERONIMO_HOME to enable the boot classpath that needs to be set. Perhaps we can do this through an environment variable that can be picked up externally...something we should definitely talk about.
Other Efforts
The first step in creating a Terracotta Geronimo plugin should be, at a minimum, to provide session clustering. Another plugin effort could also be a Terracotta EJB clustering plugin.
Resources
Some resources for building Geronimo Plugins:
The Liferay plugin does some cool one-time only setup (install database for Liferay)...all of their stuff can be found here:
http://geronimo.liferay.com/plugins/
These should give you a good basis for how plugins work.
