Customising patterns to demonstrate the capabilities of the PureApplication System

Originally posted on IBM Developer blog “Exploring PureApplication System, Software Service and more”  by Jessica Stevens on 15 May 2013 (6499 visits)

This post was written by Ewan Withers, a Senior Consultant at Icon Solutions.

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To demonstrate the capabilities of the PureApplication System, we built a test-bed application: an Internet Banking demo, based on a client’s specification (a standard multi-tier architecture, with servers running HTTP Server, WebSphere Application Server, WebSphere Message Broker and DB2). We then created an instance of the two types of Pattern:

• Virtual System Patterns (VSPs): script-configured, VM-centric, static deployments with a traditional administration model.
• Virtual Application Patterns (VAPs): application-centric “expert” components, with policy-driven automatic scaling and a Cloud-based administration model.

Porting a complex, multi-component application into a VSP should be achievable within current development frameworks; you may even be able to leverage existing deployment artifacts. Any changes required are of the same order as you would expect when performing any other kind of migration (e.g. moving from Windows to Linux, or upgrading WebSphere Application Server). We found that the benefits of the VSP can even be realized during its own development: rapid, on-demand identical deployments of Development systems accelerated the VSP’s own creation.

A radical paradigm shift with long-term benefits

Wrapping the same application in a VAP, in contrast, requires a radical paradigm shift: you need to think in Cloud-centric terms because of the opacity of the deployed VAP. A considerable amount of development effort is required, and during development of the VAP we found that there is a “sweet spot” somewhere between the following endpoints (which will vary depending on the application in question):

• Complete re-build of the application, and use of out-of-the-box VAP plugins
• Implementation of complex customized VAP plugins, and no changes to the application

The strategic application architecture plan can include movement along this continuum, with the investment being justified by the long-term benefits of the Cloud-centric deployment. As well as realising the full benefits of the PureApplication System, the VAP approach can enforce greater rigour in development standards, bringing about a general improvement in code quality.

A PureApplication System is a major long-term investment, and maximizing that investment is largely dependent on choosing the right corresponding application development strategy. The choices of VSP or VAP (or a phased approach between the two) are all entirely valid; indeed, the choice might vary for different applications – and whatever the decision, the benefits will be manifold.

We were delighted when our pattern won an Impact 2013 PureApplication Award – an award which recognises the best innovative pattern.  If you’d like to find out more, or see a demo on our pattern, contact me at ewan.withers@iconsolutions.com.

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