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Despite cloud's popularity, there are some cloud projects that just don't work. When that happens, and when you've...
determined the problem isn't just a bad choice of provider, you'll have to plan a retreat.
To carry out a successful cloud exit strategy -- where applications and data are moved as smoothly as possible out of the cloud -- you'll need to do three things: pick a landing spot, manage the technical transition and address any business or legal issues.
Step one: Pick a landing spot
If you leave the cloud, you'll have to go somewhere else. While returning to your original environment may seem appealing, there are times when it won't work. For example, you may have eliminated the in-house resources needed to run the applications you moved to the cloud -- or maybe you never ran those apps in-house at all. Even if you can revert back to your original application environment, consider a few points before taking that leap.
First, examine the changes you made to your applications before moving them to the cloud. Depending on how extensive those changes were, there are different routes to take.
If you made minimal changes to your applications, returning them to their original environment is an option -- but ensure the original resources and application versions, or their equivalents, are still available. Organizations often perform cloud migrations because in-house platforms are aging. If the original platforms are still in place, return to them and plan your evolution from there. However, if they aren't still in place, don't buy old systems. Stay in the cloud until you can build an optimal, modern, in-house facility for the applications you're taking back.
If you made significant application changes before moving to the cloud, confirm that you have a version of the applications as they originally ran. If you do, follow the same process above. If the only versions you have are rewritten to take advantage of cloud-specific features, you will have to bring the apps back in their modified state, or rebuild them.
Some users who want to move out of the public cloud see private cloud as their only option -- but that's not the case. For most businesses, virtualization is a cost-efficient and effective alternative. If you need new infrastructure to support your applications in house, consider adopting data center virtualization.
Step two: Manage the technical transition
After determining your landing spot and preparing the necessary resources, the next step in a cloud exit strategy is to manage the transition out of the cloud. This will be a reversal of the steps you took to move the applications to the cloud. You'll need to be able to load and run the apps locally, and integrate workflows between them.
The most common change organizations make to applications during a cloud migration is Horizontal scaling. Horizontal scaling allows on-premises apps to burst to the cloud for additional capacity. It also lets users add or remove application instances in the cloud, as needed. Unless you ensure an application is scalable after exiting the cloud, these benefits will be eliminated.
While it's possible to scale application instances in house through virtualization, adopt at least a simple cloud stack to manage instances. If you're using virtualization, pick a cloud stack that's compatible with your virtualization environment to facilitate migration.
A cloud exit strategy should also emphasize application lifecycle management. Organizations should test applications in their new location, and validate workflows. If you made significant application changes, or if the applications were in the cloud for an extended period, run a pilot test to ensure they run correctly before you cut over.
Step three: Address business and legal issues
The final step in a cloud exit strategy is to consider your business and legal processes. Exiting the cloud should be a last-resort option, and your cloud provider should know of any issues before you leave. When you know you're going to migrate applications back, inform your provider. However, if you need to migrate apps out of the cloud before a contract expires, consult your legal department first.
Many cloud issues, even those that force users to move applications back on premises, will likely be resolved as cloud services and applications mature. A solid cloud exit strategy should ensure you don't burn bridges with your provider, as you may come back later.
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