Cloud migration is the process of moving data, applications or other business elements to a cloud computing environment.
There are various types of cloud migrations an enterprise can perform. One common model is the transfer of data and applications from a local, on-premises data center to the public cloud. However, a cloud migration could also entail moving data and applications from one cloud platform or provider to another -- a model known as cloud-to-cloud migration. A third type of migration is a reverse cloud migration, cloud repatriation or cloud exit, where data or applications are moved off of the cloud and back to a local data center.
Why migrate to the cloud?
Cloud computing ultimately frees an enterprise IT team from the burden of managing uptime. Placing an application in the cloud is often the most logical step for growth. A positive answer to some or all of these questions may indicate your company's readiness to move an app to the cloud.
1. Should your application stay or go? Legacy applications, or workloads that require low latency or higher security and control, probably should stay on premises or move to a private cloud.
2. What's the cost to run an application in the cloud? One of the primary benefits of a cloud migration is workload flexibility. If a workload suddenly needs more resources to maintain performance, its cost to run may escalate quickly.
3. Which cloud model fits best? Public cloud provides scalability through a pay-per-usage model. Private cloud or on-premises provides extra control and security. A hybrid cloud model provides the best of both, although performance and connectivity may suffer.
4. How do I choose the right cloud provider? The cloud providers generally offer comparable services to run all kinds of workloads in the cloud, as well as tools to help you efficiently move apps there. Gauge your specific needs for availability, support, security and compliance, and pricing to find the best fit.
Benefits of cloud migration
The general goal or benefit of any cloud migration is to host applications and data in the most effective IT environment possible, based on factors such as cost, performance and security.
For example, many organizations perform the migration of on-premises applications and data from their local data center to public cloud infrastructure to take advantage of benefits such as greater elasticity, self-service provisioning, redundancy and a flexible, pay-per-use model.
Cloud migration challenges
Sometimes IT leaders discover that their applications don't work as well in the cloud as they did on premises. They need to determine the reasons for the cloud migration failure. It could be poor latency, concerns about security or perhaps compliance challenges. Often, the reason is that the cloud application has a higher cost than anticipated, or the application does not work as well as originally anticipated.
The reality is that not all applications are a good fit for the cloud. That's why it is so important for managers to scrutinize their on-premises applications carefully when they make their initial choice about which should move to a cloud environment.
The application does not need to return to its original state or to a private cloud. If the application requires additional infrastructure, a move to data center virtualization might be the right choice. The most common alteration to an app that goes to the cloud tends to be horizontal scaling, the feature that lets applications access additional resources on the cloud when they need additional capacity or lets users move apps to the cloud when needed. If you make no provisions to retain that feature, be aware that you will lose those benefits when you remove the app from the cloud.
Having a solid cloud exit strategy, where the apps and data move out of the cloud, is just as important as having a good cloud migration strategy. IT managers need to know where the data will go, how to manage the technical transition and then how to address any business or legal issues that may arise as a result of the reverse migration. Consider the changes you made prior to when you moved the application to the cloud. Moving the app back to its original platform might be one option. If those older platforms no longer exist, it will make sense to keep the application in the cloud until you can come up with an alternate solution.
A thorough cloud exit strategy should include application lifecycle management. Test the apps in the new environment before the cutover. Last, double-check potential business and legal processes. Exiting the cloud is usually a last resort, so be sure your legal department checks your contract with the cloud provider, particularly if you transition before the contract expires.
Don't underestimate proper staff training. If staff cannot be trained prior to a cloud migration, it makes sense to hire an experienced partner to manage the project.
