Book Image

Modernizing Legacy Applications to Microsoft Azure

By : Steve Read, Larry Mead
Book Image

Modernizing Legacy Applications to Microsoft Azure

By: Steve Read, Larry Mead

Overview of this book

Organizations have varying circumstances, objectives, and prerequisites when contemplating a hyper-scale cloud solution transformation to a platform such as Azure. Modernizing Legacy Applications to Microsoft Azure uncovers potential scenarios and provides choices, methodologies, techniques, and prospective possibilities for transitioning from legacy applications to the Microsoft Azure environment. You’ll start by understanding the legacy systems and the main concerns regarding migration. Then, you’ll investigate why distributed architectures are compelling and the various components of the Azure platform needed during migration. After that, you’ll explore the approaches to modernizing legacy applications and the Rs of modernizing (i.e., rehost, refactor, rearchitect, and retire). You’ll also learn about integration approaches and potential pitfalls. By the end of this book, you’ll be well equipped to modernize your legacy workloads while being aware of pitfalls and best practices.
Table of Contents (18 chapters)
1
Part 1: Legacy Estate Options
3
Chapter 2: Strategies for Modernizing IBM and Unisys Mainframes
6
Part 2: Architecture Options
10
Part 3: Azure Deployment and Future Considerations

In modernization, one size does not fit all

Everything we have talked about so far has been focused on re-architecting your monolithic workloads. You might think that this implies that you are rewriting most, if not all, of the workloads, but it does not have to always be that way. It’s time for a quick recap to make sure we are clear on semantics. Here are a couple of terms to review:

  • Rehost: Typically, this refers to taking the existing code base from the monolith and recompiling it for the x86 platform so that it can run in Azure
  • Refactor: This is very similar to rehost but implies that the language has changed, usually from COBOL (or some other legacy language) to Java or C#

Remember earlier in this chapter in the Understanding how we got here – the evolution of application development section, how we talked about how, as monoliths evolved, they started employing modular programming into their architectures? This is good news if we want to reuse...