As legacy applications outlive their usefulness, companies look toward the cloud for maximum efficiency and minimum expense. But nothing is as simple or easy as just “moving to the cloud.” Legacy applications need to be modernized, and data has to be migrated. It’s the kind of headache that makes any seasoned IT pro reach for the coffee maker -- and a fistful of Advil.
Gartner has offered five models for migration and modernization since 2011 for companies moving their apps into the cloud. Organizations can rehost the application in a different hardware environment; run their applications through a cloud provider; modify the code base; completely rearchitect the application; or totally swap out the application for something new and different that meets business requirements.
Application modernization and migration isn’t an all-or-nothing proposition, however. Some legacy applications will still be useful; others will be ready for their new home in a public or private cloud. It all comes down to evaluating what users do with the apps -- and what they don’t do. Meet with users, not just department heads, and have them walk you through their day-to-day tasks. Ask what features they need and what features they can live without. Understanding the business process behind every application is key to being able to modernize existing applications and port them over to either a public or private cloud.
Once you know what’s needed from the business side, developers can start planning. Decide how the final application will look -- what functionality it will have, what specifications it will be built on, and how it will be accessed.
In “Developing a Successful Mainframe Migration Strategy,” Wayne Kernochan, president of Infrostructure Associates, wrote that reverse-engineering the program and regenerating the application from an abstracted design model is the way to go. This approach creates minimal disruption to the end user because it allows developers to find and fix problems with the design model as a reference.
The other part -- web-servicing applications -- comes as no surprise. Web portals are familiar to users. As Kernochan wrote in “Modernizing Mainframe Applications After a Migration Project: Part 4,” as many applications should be web-serviced as possible.
From there, it’s a matter of building the application, matching up requirements with features, and ensuring that users know what to expect when the system goes live. As part of this strategy, Kernochan recommended that companies stage migrations. Falling back on the “this is not an all-or-nothing” proposition, development teams can roll out applications to different business units, leaving the old applications running just in case. This iterative approach allows IT departments to get feedback and find fixes in smaller environments, enabling them to work out bugs before the new applications are rolled out company-wide.
Most likely, it’s the path that takes the most time that will yield the best results. Remember to check every environment, not just production: development, quality assurance, and testing. Code will need checking and double-checking. Developers will spend more time with the business side than they’ll spend writing code and evaluating problems. In the end, though, the company will be able to leave legacy applications behind and move to a more flexible, scalable environment.
— Christine Parizo is a freelance writer specializing in business and technology.