You've migrated your applications and data from on-premises into the cloud. Your cloud migration is done, right?
Probably not. Although there's a tendency to think of cloud migration as a one-time journey that you complete and then never have to do again, most businesses are actually in the midst of constant cloud migration — even if they don't know it.
What Is Cloud Migration?
The basic definition of cloud migration is that it's the process of moving applications and/or data into a cloud computing environment. Cloud migration starts with deciding which type of cloud service or services to use, then modifying your current workload to fit them. Finally, you move the workload into the cloud and deploy into production.
Typically, the implication is that cloud migration involves moving workloads from an on-premises data center into some type of cloud. As we'll see below, however, that's not the only type of cloud migration out there.
Cloud Migrations Come in Many Forms
Today, more than 90% of businesses use the cloud. That means they've already completed the cloud migration process that got their workloads into the cloud in the first place.
But it doesn't mean that they're not still undertaking cloud migration. There are many types of cloud migration, and making the initial move into the cloud is only one. Others include the following:
Migrating to a new cloud service
You may have started your cloud journey by using just a few types of cloud services — like VM instances and object storage. But to take greater advantage of the cloud, you might decide to move some of your workloads to other cloud services — such as serverless functions or databases. Or maybe you choose to migrate monolithic applications to containers and deploy them in a cloud-based Kubernetes environment.
Making these types of moves requires a migration process. You typically have to make changes to the nature of your workload and configure the new cloud service to support it. That requires about as much effort as getting your workload into the cloud in the first place.
Migrating to multicloud
Deciding to expand your cloud footprint from a single cloud to multiple clouds is another form of cloud migration. Even if you use the same types of services in each of your clouds, you'll need to update your configurations and learn new tools in order to make use of an additional cloud.
Migrating to hybrid cloud
Along similar lines, cloud migration happens when you implement a hybrid cloud environment, which combines public cloud resources with private infrastructure. Hybrid cloud migrations may not require a great deal of workload reconfiguration if you use a service (like AWS Outposts or Azure Stack) that lets you manage private infrastructure through the same tools that you'd use in the public cloud. But you'll still need to provision the private infrastructure, which is no mean feat.
Sometimes, you may decide that the cloud is not working for you — at least not for all of your workloads — and that you need to migrate back to an on-prem environment.
When you do that, you undertake a cloud repatriation. Although cloud repatriation means moving applications or data out of the cloud instead of into it, it still qualifies as a form of cloud migration. It requires the same level of planning, workload modification, and actual migration as getting your workloads into the cloud to begin with.
Why Cloud Migration Never Ends
Most organizations will perform some or all of the types of cloud migrations described above. In addition to making the initial move into the cloud, they may expand into multicloud or hybrid cloud architectures, or even repatriate some of their workloads back on-prem.
Plus, in some cases, a business may end up performing the same type of cloud migration more than once. It could, for example, undertake a multicloud migration in order to add a second cloud to its architecture, then do another multicloud migration by adding a third cloud down the line.
Because of these factors, businesses should never imagine that they've moved beyond cloud migration. They should instead prepare to plan and implement cloud migrations of all types on a recurring basis. Unless you swear off the cloud entirely and forever, chances are that there are more cloud migrations in your future.
About the authorChristopher Tozzi is a technology analyst with subject matter expertise in cloud computing, application development, open source software, virtualization, containers and more. He also lectures at a major university in the Albany, New York, area. His book, “For Fun and Profit: A History of the Free and Open Source Software Revolution,” was published by MIT Press.