Mind the Gap! The Leap from Legacy to Modern Applications 

Legacy to Modern Applications | modernizing legacy applications

Most businesses today have evaluated their options for application modernization. Planned movement to the cloud happened ahead of schedule, driven by the need for rapid scalability and agility in the wake of COVID-19.

Legacy applications already rehosted or replatformed in the cloud saw increased load, highlighting painful inefficiencies in scalability and sometimes even causing outages. Your business has likely already taken some first steps in app modernization and updating legacy systems. 

Of the seven options to modernize with legacy systems outlined by Gartner, 2nd Watch commonly works with clients who have already successfully rehosted and replatformed applications. To a lesser extent, we see mainframe applications encapsulated in a modern RESTful API or replaced altogether. Businesses frequently take those first steps in their digital transformation but find themselves stuck crossing the gap to a fully modern application. 

What are common issues and solutions businesses face as they move away from outdated technologies and progress towards fully modern applications? 

Keeping the Goal in Mind 

Overcoming the inertia to begin a modernization project is often a lengthy process, requiring several months or as much as a year or more to complete the first phases. Development teams require training, thorough and careful planning must occur, and unforeseen challenges are encountered and overcome. Through it all, the needs of the business never slow down, and the temptation to halt or dramatically slow legacy modernization efforts after the initial phases of modernization can be substantial. 

No matter what the end state of the modernization journey looks like, it can be helpful to keep it at the forefront of the development team’s minds. In today’s remote and hybrid working environment, that’s not as easy as keeping a whiteboard or poster in a room. Sprint ceremonies should include a brief reminder of long-term business goals, especially for backlog or sprint reviews. Keep the team invested in the business and technical reasons and the question “why modernize legacy applications” at the forefront of their minds. Most importantly, solicit their feedback on the process required to accomplish the long-term strategic goals of the business. 

With the goal firmly in your development team’s minds, it’s time to tackle tactics in migrating from legacy apps to newer systems. What are some of these common stumbling blocks on the road to refactoring and rearchitecting legacy software? 

(Related article: Rehost vs Refactor vs Replatform | AppMod Essentials) 

Refactoring 

Refactoring an application can encompass a broad set of areas. Refactoring is sometimes as straightforward as reducing technical debt, or it can be as complex as breaking apart a monolithic application into smaller services. In 2nd Watch’s experience, some common issues when refactoring running applications include: 

  • Limited knowledge of cloud-based architectural patterns.
    Even common architectures like 2- and 3-tier applications require some legacy code changes when an application has moved from a data center to a cloud service provider or among cloud service providers. Where an older application may have hardcoded IP addresses or DNS, a modern approach to accessing application tiers would use environment variables configured at runtime, pointing at load balancers. 
  • Lack of telemetry and observability.
    Development teams are frequently hesitant to make changes quickly because there are too many unknowns in their application. Proper monitoring of known unknowns (metrics) and unknown unknowns (observability) can demystify the impact of refactoring. For more context around the types of unknowns and how to work with them in an application, Charity Majors frequently writes on the topic. 
  • Lack of thorough automated tests.
    A lack of automated tests also slows the ability to make changes because developers cannot anticipate what their changes might break. Improved telemetry and observability can help, but automated testing is the other side of the equation. Tools like Codecov can initially help improve test coverage, but unless carefully attended, incentivizing a percentage of test coverage across the codebase can lead to tests that do not thoroughly cover all common use cases. Good unit tests and integration testing can halt problems before they even start. 
  • No blueprint for optimal refactoring.
    Without a clear blueprint for understanding what an optimally refactored app looks like, development and information technology teams can become frustrated or unclear about their end goals. Heroku’s Twelve-Factor App methodology is one commonly used framework for crafting or refactoring modern applications. It has the added benefit of being applicable to many deployment models – single- or multiple-server, containers, or serverless. 

Rearchitecting

Rearchitecting an application to leverage better capabilities, such as those found in a cloud service provider’s Platform-as-a-Service (PaaS) or Software-as-a-Service (SaaS) options, may present some challenges. The most common challenge 2nd Watch encounters with clients is not fully understanding the options available in modern environments. Older applications are the product of their time and typically were built optimally for the available technology and needs. However, when rearchitecting those applications, sometimes development teams either don’t know or don’t have details about better options that may be available. 

Running a MySQL database on the same machine as the rest of the monolithic application may have made sense when initially writing the application. Today, many applications can run more cheaply, more securely, and with the same or better performance using a combination of cloud storage buckets, managed caches like Redis or Memcached, and secrets managers. These consumption-based cloud options tend to be significantly cheaper than managed databases or databases running on cloud virtual machines. Scaling automatically with end-user demand and reduced management overhead are additional benefits of software modernization. 

Rearchitecting an application can also be frustrating for experienced systems administrators tasked with maintaining and troubleshooting production applications. For example, moving from VMs to containers introduces an entirely different way of dealing with logs. Sysadmins must forward them to a log aggregator instead of storing them on disk. Autoscaling a service can mean the difference between identifying which instances – of potentially dozens or hundreds – had an issue instead of a small handful of them. Application modernization impacts every person involved with the long-term success of that application, not just developers and end-users. 

Conclusion 

Application Modernization is a long-term strategic activity, not a short-term tactical activity. Over time, you will realize the benefits of the lower total cost of ownership (TCO), increased agility, and faster time to market. Recognizing and committing to the future of your business will help you overcome the short- and mid-term challenges of app modernization. 

Engaging a trusted partner to accelerate your app modernization journey and lead the charge across that gap is a powerful strategy to overcome some of the highlighted problems. It can be difficult to overcome a challenge with the same mindset that led to creating that challenge. An influx of different ideas and experiences can be the push development teams need to reach the next level for a business. 

If you’re wondering how to modernize legacy applications and are ready to work with a trusted advisor that can help you cross that gap, 2nd Watch will meet you wherever you are in your journey. Contact us to schedule a discussion of your goals, challenges, and how we can help you reach the end game of modern business applications. 

Michael Gray, 2nd Watch Senior Cloud Consultant 


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