Tuesday, 23 September 2008

WAS V7.0 Cluster Bus Member Wizard

There's a really neat consumability improvement in WAS V7.0 in the shape of the new console wizard that guides you through configuration of a cluster bus member. The new wizard is invoked when you click "Add" to create the bus member for a cluster.

If you've ever added an appserver cluster to a bus, then you'll probably agree that anything other than a simple "HA" setup was pretty hard to configure - if you wanted to create multiple messaging engines to operate in parallel within the cluster then it's likely that you needed to create your own core group policies, and configure their match criteria and properties. If you made a mistake along the way you probably only found out later because the engine wasn't running on the server you expected, or wasn't failing back to a preferred server after recovery. The reason was often that the match criteria contained a typo and the engine was not bound to the policy you intended.

The new cluster bus member wizard in V7.0 spares you from having to worry about any of that, by providing a pattern-based approach to creation of the cluster bus member. On launching the wizard, you can select one of a small number of patterns and the wizard then sets up the messaging engines and core group policies with settings that corresponding to the pattern. The patterns cover the popular uses; you can select "high availability" if you want a single engine that can failover, or you can select "scalability" if you want multiple engines. There's also a pattern that provides both of the above.

The new console wizard makes life really easy by saving you from having to enter the core group policies by hand. It also provides feedback on your curent configuration and provides hints about how to improve it. For example it'll spot that you might have asked for a highly available bus member, but your whole cluster is running on one node. You can do that if you want, but the node is a single-point-of-failure and the wizard will detect it and politely suggest that might want to remove the SPOF.

If your browser supports SVG you even get a visual representation of the cluster showing the nodes and servers and the messaging engines.

The visual aspects of the wizard and the amount of work it saves you make it a pretty useful addition to the console.