Cloud migration describes the process of moving data, applications, and other IT processes from on-premises or legacy infrastructure to one or more clouds. It can also mean transferring digital workloads from one cloud platform or service provider to another.
“Legacy” assets are hardware or software that is old and outdated but still being used. Typically, it is housed in an organization’s on-premises datacenter, often in the same building where employees are located. Legacy systems are generally much less efficient, fast, and secure than modern platforms. They can slow down the company’s business processes, hampering its ability to compete effectively. They are also more vulnerable to hacking and cybercrime.
If sufficiently outdated, legacy applications are no longer supported by the original vendor with upgrades and patches. The same is true for aging infrastructure like servers, networking systems, databases, and other hardware and software components.
The best exit strategy from relying on legacy infrastructure is migrating to the cloud, which rewards users with intuitive, Internet-enabled features and provides IT with a much more efficient, secure, and cost-effective operating environment.
Learn more about public vs private vs hybrid cloud
Public cloud
When people say just “cloud,” they are usually referring to public clouds, computing environments run and maintained by cloud service providers, made available to client companies for a fee, and accessed by users over the Internet.
Private cloud
A private cloud is computing infrastructure dedicated to a single organization and not shared with anyone else. Private clouds are most often situated at the organization’s own facility but can also be hosted on the premises of a services provider.
Hybrid cloud
As the name implies, this configuration combines public and private clouds – often more than one of each – linked tightly together.
Multicloud
First introduced to define a combination of two or more public clouds, the term multicloud has broadened in scope to embrace architectures that contain a private cloud as well. Also known as a hybrid multicloud, this kind of environment is becoming increasingly common.
Businesses stand to gain a host of benefits from cloud migration:
Elastic Scalability
Cloud infrastructure easily scales up or down on demand to meet your changing levels of application traffic, so you only use (and pay for) the resources you actually need.
Lower costs
The cloud eliminates the large upfront IT infrastructure purchase and ongoing operations and maintenance costs that come with traditional on-premises data centers. A pay-as-you-go subscription covers everything and saves you the overhead of funding a large in-house IT department focused on keeping things running.
Higher productivity
Your cloud provider manages the complexities of infrastructure so you can concentrate on business innovation. IT simplicity and remote accessibility free your teams to collaborate efficiently across geographies and time zones.
Business agility
Additional IT resources can be provisioned in the cloud whenever needed, enabling you to quickly gear up to respond to market opportunities when they arise.
High security
Cloud providers typically have robust, multi-layered security built into their architecture – providing better data and application protection than many on-premises environments.
Moving databases
Database migration can be a real challenge, especially for large data volumes. Many companies choose to alleviate the pain by transitioning legacy applications to modern architectures gradually, moving one portion at a time, and starting with a private cloud. The MongoDB database provides an ideal solution, as it runs identically everywhere. Once your newly revamped applications are ready to be moved to a public cloud, you can do so without having to rearchitect your database. For even greater management ease, MongoDB is available as an on-demand, fully managed Database as a Service (DBaaS) in the cloud, called MongoDB Atlas.
Interoperability
Many applications don’t readily communicate with some cloud environments, and may need to be adapted.
Data integrity
Cloud providers’ security and privacy policies may not be a good match for the requirements of highly regulated industries. This is why government agencies and companies dealing with sensitive and confidential data usually opt for a private cloud that lets them retain more control.
Resource management
It’s not uncommon for veteran IT staff to be skeptical about cloud infrastructure and inexperienced in working with it. Consider bringing in expert consultants to deliver advice, retraining, and upskilling.
There are five cloud migration strategy options, known as the “Five R’s” as enumerated by leading research group Gartner:
Rehost
This is the simplest of options, also called “lift and shift.” Basically, it amounts to simply redeploying existing applications on cloud infrastructure without any modifications. The approach makes the most sense for companies new to cloud computing , especially when moving applications that would be expensive and time-consuming to alter.
Refactor
This next level of complexity, also known as “lift, tinker, and shift,” involves some changes to optimize the application for cloud infrastructure, without going as far as modifying the core software architecture.
Revise
Here, developers proficient in cloud infrastructure undertake major application surgery, rewriting and expanding the code base to take full advantage of the cloud environment. The modified application is then migrated by rehosting or refactoring.
Rebuild
In cases where nothing short of a total revamp will do, the existing code base is scrapped altogether and the application is totally rearchitected to take maximum advantage of cloud features.
Replace
Companies can simply opt to switch to a pre-built, cloud-native application from a popular and proven SaaS vendor. Existing application data is the only element that needs to be retained and migrated to the new platform.
A migration going from on-premises to the cloud varies according to a company’s individual needs, but most processes include these phases:
Set goals
Determine objectives and a timetable for your cloud deployment, to use as yardsticks for measuring success.
Plan a security strategy
Security is different in the cloud: your assets aren’t protected by a firewall, and security policies are controlled by the service provider instead of by you. It’s important to harmonize your requirements with their safeguards to determine whether you need to layer in added protections of your own.
Replicate your data
Data has to be moved from your on-premises systems to the cloud. This is much more easily achieved with a database like MongoDB which runs identically in all environments.
Migrate existing software assets
This may require refactoring or a wholesale code rewrite, as described above. Monolithic legacy applications can be broken up into parts and migrated gradually, or moved as a whole.
Go live
Once all these processes are complete, you then switch production over to your newly-created public cloud environment.