Lessons from migrating a critical, national legacy system to Open Source and the Cloud

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Written by Justin Hassall, Transformation Director, Informed Solutions

We have recently completed a migration of the Driver Vehicle Licensing Agency’s (DVSA’s) Testing and Registration System (TARS) to the cloud. TARS is a suite of complex legacy systems that deliver a critical public service: managing driving tests nationally.  As an example of transformation of a national legacy system to open source and the cloud I wanted to share the journey.

TARS was built on a legacy technology stack and hardware that was fast approaching end of life. DVSA wanted to migrate to a more robust and stable cloud-based environment, underpinned by DevOps best practices that would enable them to manage the service in a more responsive, reliable, resilient and cost effective way.

Our role was to act in an “intelligent client” capacity, providing delivery management and architecture assurance to a complex, multi-supplier software and hardware migration project.  We worked collaboratively with the team to put in place Agile practices and delivery structures to drive towards a ‘one-team’ working model, including providing coaching and ongoing guidance to other suppliers who were less familiar with Agile working

The project had some challenging timescales driven by end-of-life hardware and a fixed date for the end of the existing support contract.  The project also presented significant technical challenge, with some applications more than 10 years old requiring re-platforming from deprecated and out-of-support technologies, and the introduction of cloud-native solutions where original functionality was no longer supported, or would not operate as required in a resilient and scalable multi-availability zone environment.  

The project also had the potential for significant reputational risk: the TARS solution is a highly visible citizen-facing service, providing the end-to-end processing of over half a million driving tests and examinations a year, so it was critical that the migration minimised downtime and disruption to the public, examiners and several hundred testing centres across the country.

We provided the overarching governance and architecture support DVSA needed in operating a multi-vendor migration approach which combined DVSA’s own teams (including business representatives, service owners, enterprise architects and a testing team), a team of DevOps and platform engineers to build out the target cloud environments and Continuous Integration pipelines, and an application migration team (including offshore developers) in a one-team model.

The underpinning technology was successfully migrated from a highly COTS-based stack to a more flexible Open Source based stack, offering significant savings in licensing costs and reducing supplier lock–in.  In parallel, the applications were migrated from on-premise physical servers to the AWS cloud, with a full CI pipeline developed (based on Git, Maven, Jenkins, Terraform, Selenium and JMeter) to automate build, release, creation of infrastructure as code, deployment and testing, significantly reducing the cost and risks associated with rolling out ongoing improvements to the service.

As a result of the project, the TARS suite of applications is now based on fully supported and largely open source enabling technology, and hosted in a highly available, scalable and robust multi-availability zone environment.  This offers a more stable service to the public which is supportable by different vendors providing better value for the taxpayer.

DVSA report operational cost savings through reduced COTS licence costs, as well as moving to a ‘pay as you use’ hosting model.  Putting in place an end-to-end Continuous Integration pipeline, automated testing and DevOps practices has reduced the cost of releasing further updates and improvements, providing increased responsiveness in meeting user needs and delivering ongoing software updates and patches.

There have been some key areas of learning which are clearly applicable to any national scale migration from a legacy system.

We had to manage the inevitable uncertainties associated with migration of legacy systems, such as ensuring that solutions to specific technical issues were developed ‘in-the-round’ (including adoption of more modern architectural patterns and cloud-ready technologies wherever appropriate) approved by architects, integrated into delivery plans and assured.

Also reporting proved key, with a detailed, impartial view of progress, issues and risks (including the production of automated reports on delivery progress and software quality through configuration of JIRA and Confluence) to enable intelligent decision making and management of the project.

You certainly need to be able to articulate complex technical and delivery concepts and challenges in straight-forward terms and highlight the practical business risks and blockers so that the organisation’s leaders (without deep IT expertise) are able to act on progress, key risks and issues throughout the project.

So in summary, it’s been hard and challenging work, but shows it can be done. I was pleased to hear our client Alex Fiddes, DVSA’s Programme Delivery Executive recently saying that  “Informed Solutions has provided DVSA with invaluable and impartial expertise, support and assurance which enabled DVSA to successfully deliver the complex, multi-vendor TARS Stabilsation project to challenging timescales”


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