In the second edition of its ebook Enterprise Cloud Strategy, Microsoft states the important fact that “every journey must have a sense of its destination, its road and when it will arrive. A migration journey to the cloud is no different”.
Cloud thinking milestone
“One should not miss out on the opportunity to modernize. Actually, a milestone is reached when you start planning a move towards the cloud. At this point, it is time to consider the IT ecosystem as a whole and how you can modernize it,” says Geir Morten Allum, Senior Cloud Architect at Basefarm.
In 2011 Gartner outlined the 5 different strategic R’s for application migration to the cloud: Rehost, Refactor, Revise, Rebuild and Replace.
As time has passed, IT professionals seem to stick to slightly different R’s, for instance Retire, Replace, Retain/wrap/expand, Rehost and Re-envision.
“An implementation of a DevOps culture will for many customers increase their productivity in their R strategy,” Allum says.
If a legacy application is providing little value compared to its costs, it might be time for retirement. Other legacy applications can provide some value, but off-the-shelf replacements with lower total costs of ownership are available.
Many legacy applications were originally built because there was no alternative at the time. A modern, readily available application – maybe a cost-effective SaaS – could replace the old one sufficiently and even replace multiple legacy systems.
Retain or rehost
Retain, wrap and expand might be the strategy for legacy applications providing good value with acceptable total cost of ownership (TCO). A modern wrap around can gain additional value and benefits. Examples are adding external application functionality through APIs or extending the legacy application with third party tools. Through this, you can obtain a hybrid cloud solution.
If a legacy application is providing good value but is expensive to run, it might be a candidate for rehosting. Rehost “lift and shift” involves keeping the same basic functionality but moving to the cloud where it is easier and less expensive to run. You abandon old hardware and might be blessed with simple migration if the application runs on a virtual machine (VM) which easily relocates.
If a legacy application is providing good value but cannot be easily moved, the best solutions might be to re-envision it and build it again in the cloud with modern technology, architecture and practices. Re-envision normally also involves adding more business value to core functionality and making it service-oriented.
So when putting together your cloud migration strategy the first thing to do is to put together a cloud strategy team with all the stakeholders and you might need to pslit them into various sub groups according to Allum. He continues “pay attention to how the finalized cloud environment should work. Could a preexisting SaaS-model replace the legacy app? Should you move from hardware to an IaaS or even further to a PaaS leaving infrastructure entirely to the cloud service provider?”
There are a lot of questions and not one easy answer, however waiting with your cloud migration is not an option so start preparing today if you have not yet done it!
IaaS, PaaS and SaaS in brief
Infrastructure as a Service (IaaS): You leave the cloud provider with all hardware issues. With IaaS, these resources are available as a service. You can create, reconfigure, resize and move instantly. Sometimes also explained as hypervisor as a service.
Platform as a Service (PaaS): A platform for creating and delivering software over the web. Developers work without worrying about updates, operating systems and load balancing. Serverless is also used within PaaS; here the server management and capacity are completely hidden from the developer.
Software as a Service (SaaS): Software is hosted on remote services. Salesforce, Office 365, 24SevenOffice, Dropbox and Mailchimp are some SaaS products. The users need not worry about hardware, software updates and patches, and are in business as long as their internet connection is up.
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