Migration

IaaS or PaaS – Migrating Legacy Microsoft Applications to Azure ‘Business as a Platform’

Best practices for migrating legacy Microsoft applications to PaaS

Determining whether to migrate to IaaS (“lift and shift”) or PaaS highlights the value of the first Digital Transformation planning process, to identify whether the benefits sought are purely related to the replacement of server hardware, or if transformation of software development and business process are also key goals.

This is effectively explored through this Microsoft use case solution Migrating Legacy Microsoft Applications to Azure ‘Business as a Platform’.

Cloud Solution Design

In their white paper Microsoft IT transitions core business applications to Microsoft Azure PaaS, Microsoft explores the dynamics that can be considered when determining whether IaaS, PaaS or SaaS is the right option for your Cloud Migration project, through detailing a number of their own migration case studies.

This decision process is central to Cloud Solution Design.

Cloud Transformation Roadmap

The primary output of the first phase is the scope definition, which will shape the nature of the required migration work.

For example if it is identified as a purely ‘Lift and Shift’ objective, then this will mainly require a relatively simple process of mapping computing load requirements to their Cloud service equivalents. This is effectively illustrated through this Microsoft case study.

Still within only a Technical scope the migration may also seek to modernize the database layer, like Netlix migrating away from a legacy data-centre Oracle approach to a Cloud Native one of Cassandra and MySQL databases. In this scenario the bulk of the hard work centred around the intensive data migration, not the Cloud hosting component.

The scope can also range through to the wholesale re-engineering of applications and even business models, entirely changing how the organization conducts its business processes, and it could also include a large-scale, enterprise-wide campaign to drive Cloud adoption across the entire organization via one sweeping initiative that encompasses thousands of applications.

It may also be at the other end of the scale, an ultra-simple process where the business needs of a project would be best served by the adoption of a single SaaS application, with no technical migration work needed at all, the effort would entirely be focused on user adoption and training.

Therefore an effective Cloud Migration planning approach must be able to address this entire breadth and depth, and to this end a number of case studies from Microsoft, BT and Credit Suisse are referenced to define the best practices required to articulate a full Cloud Transformation Roadmap.

Enterprise-wide Cloud Solution Design

Microsoft offer themselves as a case study as well as a source of best practices. In this case study they describe their own enterprise-wide initiative to encourage all of their departments to shift away from legacy IT to their own Azure Cloud.

This required moving approximately 2,100 line-of-business applications to the cloud platform, applications that are spread across eight datacenters worldwide, comprising over 40,000 distinct operating system instances.

Microsoft started a central group of Cloud experts, the ‘Stratus’ team, to work collaboratively with departments to build their migration roadmaps, and defined a portfolio management framework where applications are priortized for migration based on a number of key criteria such as the simplicity of the application migration effort and it’s business criticality.

Another Microsoft presentation provides a detailed methodology for this portfolio approach, described in detail as Cloud Solution Design.

Defining a core solution design method of ‘Cloud Pattern Matching’, a process of mapping functionality needs to the appropriate IaaS, PaaS or SaaS option, this would equally address the simple through complex requirements; for example mapping one departments needs to a suitable SaaS option.

PaaS-Enabled Innovation

The goal of the project was to modernize a number of LOB (Line of Business) applications, such as BCWeb (Business Case Web), a web-based application used to create business cases for exemptions to product pricing, as well as other key internal apps for employee functions.

The decision to opt for PaaS was for two main reasons:

  • PaaS handles low level maintenance functions such as patching, that didn’t add any value to the goals of this project.
  • As the LOB applications were of critical importance to Microsoft sales activities requiring ongoing customization to business needs, they wanted more direct developer control than SaaS enables.

Sharepoint to Azure Transformation

BCWeb was originally developed as a Sharepoint application, highlighting another decision possibility for migrating legacy apps to the Cloud, in that a ‘lift and shift’ option is possible, through migrating on-premise Sharepoint to Azure-based Sharepoint hosting, or even to Office 365.

In the case of this project they moved away from Sharepoint and re-built a new application based on PaaS, describing the mapping of Sharepoint functions to their modernized equivalent on Azure:

  • Web-based user interfaces mapped directly to Azure web roles.
  • WCF (Windows Communication Foundation) Services and background processes were split into two worker roles (Web and worker roles explained by TechTarget).
  • SQL Server database mapped to Azure SQL Database.

This approach delivered business benefits including:

  • Increased performance and stability – Traffic loads for the prior Sharepoint-based system had exceeded what the infrastructure could handle, and it became unstable and went offline during peak usage times at month ends, and attempts to alleviate the issue such as load balancers and architecture improvements failed to remedy the situation. Moving to Azure applied Cloud-scale capacities that eliminated the issue.
  • Cost savings / avoidance – Eliminated the requirement to procure and maintain servers.
  • Best practices and reusable components – The team developed practices and components to support the migration that other Azure projects could benefit from.

Agility

An example of the benefits of growing best practices is the second of the application case studies.

The ‘Connect’ application was used for employee performance reviews and ran on a large web cluster that sat idle for much of the year, because of the infrequent schedule of conducting the reviews. Not only were they able to also migrate this app to an elastic Cloud supply that easily scales to service more than 120,000 employees and eliminate the servers, but the new app was built from scratch in only four months.

Secure, Real-time Architecture

The third case study for the ‘Paystub’ application highlights the serious issues that some poorly architected legacy applications can cause. In this case it pulled and maintained a local copy of personal data, presenting privacy and security risks and requiring batch job synchronization, causing data latency problems.

Furthermore the business logic was programmed directly into the user interface, so even the smallest of business workflow-level changes required source code reengineering and distribution. The application also required a dedicated server cluster.

So again migrating to Azure eliminated these hardware costs, but more importantly enabled architecture modernization that also eliminated the more severe issues caused by the poor design model, making possible a single data source, real-time approach.

Delivering Business Value

The ‘Returns Service’ was how Microsoft customers would arrange for the return of products via the online and retail stores. It was painful for customers because it was manual, slow and sometimes introduced errors such as assigning refund credit incorrectly. Customers had to wait 24 hours to receive a shipping label.

Therefore in this case migrating the app to Azure delivered customer value. Integrating with the online store it enabled self-service submitting of return requests, eliminating the delays and errors and greatly improving the customer experience.

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IaaS or PaaS - Migrating Legacy Microsoft Applications to Azure 'Business as a Platform'

Best practices for migrating legacy applications to Microsoft Azure PaaS.
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