Rehosting (Lift and Shift)

What Is Rehosting?

Rehosting, commonly called lift and shift, means moving an application to new infrastructure, typically from on-premises servers to cloud virtual machines, without altering its code or architecture. The application runs as it did before. Only the ground beneath it has changed.

It is the fastest and lowest-risk route to leave a data center, which is why it is popular when a lease ends or hardware reaches end of life. It is also the route that changes the least. Whatever technical debt the application carried on-premises arrives intact in the cloud, along with its licensing terms and its inefficiencies.

Rehosting also answers a question that decommissioning asks first: does this application deserve to move at all? Rehosting an application that has few users, duplicates another system, or exists only for its data means paying to relocate something that should have been retired.

Key Points

• Fastest path off the old infrastructure. No code or architecture changes means shorter timelines and fewer surprises.
• Technical debt travels with it. Rehosting relocates problems rather than resolving them.
• Cost savings are not automatic. Workloads sized for peak on-premises capacity can cost more in the cloud if migrated unchanged.
• Licensing can complicate it. Some software licenses are tied to specific hardware or environments and need renegotiation.
• Inventory first. Applications that should be retired should not be rehosted. Sorting them out beforehand avoids paying to move dead weight.

Common Use Cases

Data center exit deadline

A hosting contract or lease ends on a fixed date. Applications that must survive are rehosted quickly, and the rest are archived and retired.

Hardware end-of-life

Servers are out of vendor support. Rehosting the application to virtualized infrastructure removes the hardware risk without a rewrite.

First step in a longer program

A team rehosts now to meet a deadline, planning to replatform or refactor once the pressure is off.

Rehosting vs. Related Concepts

Rehosting sits at the shallow end of the modernization spectrum.

REPLATFORMING

Moves the application with some adaptation to the new platform, such as using a managed database. A step deeper than rehosting.

REFACTORING

Restructures the application’s code for better maintainability or scalability. The deepest change, and the slowest.

APPLICATION RETIREMENT

The alternative to moving at all. Rehosting relocates an application. Retirement removes it and archives its data.