Last week we laid out some basics of what we call the “Full PaaS” approach to legacy app modernization. While it might not make sense in every situation, we recently completed a modernization effort using the Full PaaS approach. Here’s some background on what went into this application modernization strategy and the steps we took…

Stop Playing Legacy App “Whack-a-Mole”

Our enterprise customer developed and owned a budgeting application. The application was over five years old and built on tech that — while modern at the time — had become “stale” over the years.  Usage patterns for the application included huge spikes in demand during specific times of the year, and the need to meet these demands prompted the team to “reactively” invest in servers with more memory, better networking equipment, and other fixes. Problems were only addressed as they cropped up, with no time for long-term planning.

Yet despite throwing money and equipment at those problems, the issues with the platform continued, while customers were demanding more functionality. Unfortunately, since most of the application team’s time was spent reacting to operating issues, that simply couldn’t happen. Additionally, the application team’s O&M budget shrank over time, leaving a smaller staff responsible for the application.

After analyzing the application, we determined that three tiers of the application (compute, cache, database) could be moved to the “as-a-service” model with a reasonable amount of refactor, for two main reasons:

• This model would address the seasonal demand challenges by leveraging “auto-scaling” capabilities built directly into the services the application would now be consuming.
• As an added benefit, these services allowed scripted deployments, automated monitoring, and easier provisioning of “test” environments to get new features in the hands of users more quickly.

The 7 Steps to “Full-PaaS” Modernization

Once we chose the Full PaaS approach, we completed the modernization effort by following these seven (high level) steps:

1. Analyze application dependencies: This includes compute and data tiers, software architecture, reliance on existing resources.
2. Identify services to replace legacy components: Not everything will port directly, so map out your replacements ahead of time.
3. Establish candidate PaaS architecture: Choose your PaaS cloud platform, specific services to be used, and architect the flow of communication between the services.
4. Validate with internal stakeholders: We talk to everyone from operations staff to security to business users of the application.
5. Refactor your application code: Target the PaaS services included in the candidate architecture.
6. Automate your application delivery and integrate CI/CD: This is one of the biggest benefits to this modernization approach, so take full advantage of it!
7. Establish a living roadmap for ongoing improvement: We’re looking for both ongoing improvements to delivery automation and for any additional applications that can also adopt the model.

Interested in learning more about how AIS utilizes PaaS cloud platforms to support customers’ application modernization strategy? See here how we were able to help the US Military Branch with an Azure PaaS strategy.