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

Understanding Azure’s approach to availability and resiliency

As we mentioned previously, availability and resiliency were designed into Azure from the very beginning. A good example of this is how storage is presented to the user. If you create a managed disk in Azure that you want to use to store data, it will appear as one disk that you can mount and use. Azure maintains, at any given time, three copies of that disk for built-in, behind-the-scenes redundancy. The same is true for other storage offerings as well.

This is a good example in that it shows that the fundamental services that you rely on within Azure have availability and resiliency built in from their inception. But as we move up the application stack of services, we will require more features to provide the same level of coverage. Let’s start with a simple example that you have probably encountered before. If I deploy an application to an Azure VM, that’s great, but if that VM goes down, so does...