Shreedhar is announcing a new build release for Shoal 1.1, the GlassFish dynamic clustering framework. Version 1.1 is work in progress and offers a JoinedAndReadyNotificationSignal, multiple clusters support for the same member (useful for Sailfin's Converged Load-Balancer), cross subnet clustering support, etc.

The most important driver for the Shoal project lately has been the Sailfin project (now in alpha stage). Compared to HTTP, SIP sessions are smaller in size but greater in number so this has been a very interesting set of constraints for this group management and data replication technology.

If you're new to the technology, Shoal is at the heart of the GlassFish v2 clustering architecture and uses JXTA as an underlying technology. This article is a nice introduction if you're new to the technology which is also used in other projects such as GreenFire.

Most GlassFish subprojects (Grizzly, Metro, Woodstock, HK2, Jersey, mq, Mojarra, ...) can be used independently from the application server. Project Shoal is no exception. This Group Management Service used by GlassFish clustering can also be applied to other use-cases.

Community members Juan Pedro Danculovic and Diego Naya have a nice article over on java.net covering in a single place most of the Shoal features. It goes into the definition of all the basic terms such as Group, Member, Member Token, Spectator, Core, Group Management Service, Components, and Signals. The article also covers how to integrate your own code into the clustering infrastructure (not only for Java EE applications, but SE applications too). Given the artifact's size (JARs are less than 2MB), together with a stripped-down GlassFish v3, the possibilities become very interesting.

Previous Shoal resources include:
•  Previous Shoal posts
•  Other introductory Shoal article
•  GlassFish podcast interview about GlassFish Clustering and Shoal

A reminder from Harpreet and Ludo that tomorrow, Tue, April 17th (2007) is the GlassFish Users Group meeting in Mountain View, at the Googleplex. The meeting will be at Tunis Conference Room, (Bldg. 43). Full details here; you can also check the previous announcement, and the official announcements ([1], [2]).