“Lift and shift,” also known as “rehosting,” is the process of migrating an exact copy of an application or workload, together with its data store and operating system (OS), from IT one environment to another—usually from on-premises to public or private cloud.

Because it involves no change to application architecture and little or no change to application code, the lift and shift strategy enables a faster, less labor-intensive and (initially) less-costly migration compared to other processes. It’s also the fastest and least-expensive way for an organization to begin shifting IT dollars from capital expense (CapEx) to operational expense (OpEx) in order to initiate a hybrid cloud strategy and begin leveraging the more economical and extensible computing power, storage, and networking infrastructure of the cloud.

In the earlier days of cloud computing, lift and shift migration was worth considering for all but the oldest, most complex and most tightly coupled on-premises applications. But as cloud architectures have evolved—and enabled improved developer productivity and ever more favorable cloud pricing models—the long-term value of migrating an application ‘as-is’ that cannot leverage the cloud environment has diminished dramatically.

Today, lift and shift is considered primarily as an option for migrating workloads that are cloud-ready to some degree (e.g., VMware workloads, containerized applications, apps built on microservices architecture) or as a first step in the process of rearchitecting a monolithic application for the cloud, on the cloud.

Compared to continuing to run an application on-premises, lift and shift migration can offer several compelling benefits:

• A fast, cost-effective, minimally disruptive migration: Lift and shift lets you migrate quickly, without dedicating a large team to the task. The on-premises application can remain in place during the migration so that there’s no interruption of service, and the application experience remains identical to users.
  
  
• Potential for improved performance: Lift and shift offers the opportunity to run applications on updated, better-performing hardware, without having to purchase the hardware yourself.
  
  
• Expanded capacity while consolidating on-premises: Add compute capacity, storage, and additional network bandwidth from the cloud on a pay-by-use basis while consolidating your on-premises data center infrastructure and costs at the same time.
  
  
• Scalability on demand: Lift and shift can enable your organization to scale an application without purchasing and physically installing new computing capacity. You also won’t have to overprovision hardware to account for peak traffic periods.
  
  
• Cost-saving elasticity: Some applications may also take advantage of cloud elasticity—the ability to automatically spin-up and spin-down resources to precisely match demand. The greater your cloud’s elasticity and the more your application can leverage it, the more you stand to save by using only exactly the resources you need at any given time.
  
  
• Enhanced security: Once migrated, even legacy applications may be able to take advantage of cloud security services such as role-based access control, multifactor authentication, and unified hybrid security processes.
  
  
• Reduced on-premises data center costs and headaches: The more applications you can migrate to the cloud, the faster you can scale down your on-premises infrastructure and the costs of managing and maintaining it.
  
  
• A simple first step toward a hybrid cloud: Lift and shift is an easy way to move the applications most ready and best suited to a private or public cloud while you continue to host other applications workloads on-premises. With the proper management tools, you can manage the platforms together as a single, optimized infrastructure.

Again, lift and shift will not produce these benefits for all applications. An application that’s only partially optimized for the cloud environment may never realize the potential savings of cloud and may actually cost more to run on the cloud in the long run. If an application runs slowly or inefficiently on-premises, it is unlikely to run any better on the cloud without modification. Licensing costs and restrictions may make lift and shift migration prohibitively expensive or even legally impossible.

VMware virtualization technology is ubiquitous in the enterprise. VMware represents 80% of the virtualization market, and 100% of the Fortune 100 use VMware to virtualize their on-premises data centers. Not surprisingly, most cloud providers offer VMware infrastructure for hosting applications, and some offer specialized tools and services for lift and shift VMware migrations to their clouds.

To lift and shift an existing VMware workload, the on-premises data center and the target cloud data center should share the same underlying VMware ESXi hypervisor and a common set of VMware- and vSphere API-compatible management tools and scripts. The cloud provider should have an operations team with the skills and experience to manage the VMware software stack.

The key technology that simplifies a lift and shift VMware migration is VMware HCX (Hybrid Cloud Extension), a tool that essentially extends the on-premises network to a VMware environment on the cloud in order to rapidly implement a hybrid cloud infrastructure. HCX enables secure, large-scale migration of thousands of virtual machines (VMs) as-is from on-premises to the cloud; lets you manage and operate on-premises and cloud workloads using the same tools, scripts, and skills; and lets you implement replication and recovery of your on-premises workloads in the cloud.

Lift and shift is an IaaS (Infrastructure-as-a-Service) migration—you’re moving applications as-is from your on-premises infrastructure to cloud infrastructure that you pay for on a subscription or metered-by-use basis.

Broadly speaking, there are two other types of cloud migration to consider:

PaaS migration
A PaaS (Platform-as-a-Service) migration involves revising your application to take greater advantage of the cloud provider’s PaaS stack. You might refactor or replatform the application, making small changes to optimize its performance for cloud or to leverage specific cloud capabilities, without changing the user experience. You also might rearchitect the application to get the benefits of microservices, containers, or serverless computing. Or, you might completely redesign the application using the cloud provider’s development tools and platform capabilities that improve developer productivity.

Compared to lift and shift, PaaS migration is more costly, labor-intensive, and time-consuming up front. But it enables your application to take greater advantage of cloud-native operations automation, developer productivity, security, resiliency, and pay-per-use cost models, which together can quickly recover your initial investment.

SaaS migration
SaaS (Software-as-a-Service) migration means replacing your on-premises app with a ready-made, cloud-based alternative that provides the similar functionality and leverages more of the benefits of your cloud provider’s infrastructure.

The right SaaS migration can deliver the low migration cost of lift and shift with the cloud advantages of PaaS migration. However, it might also require you to forego or wait for certain features or customizations, and you’ll most likely need to adopt the SaaS application’s facilities for data management, access control, security, and more.

To repeat, as cloud technologies continue to boost developer productivity and improve cloud pricing models, it makes less and less sense (and costs more and more in the long run) to migrate a cloud that doesn’t leverage the cloud environment. But, there are a still a few instances in which lift and shift can make more sense than a PaaS migration:

• Your on-premise infrastructure costs are skyrocketing, but you’re not quite ready to rearchitect your applications. In this case, it may pay to briefly ‘park’ the applications on the cloud until you’re ready or able to rebuild. Exceptions are resource-intensive legacy applications such as big-data analytics, digital animation, or medical or engineering imaging that tend to ratchet up pay-by-use cloud fees more quickly than you can predict.
  
  
• You want to migrate off-the-shelf applications. You can’t rearchitect those, so the only real alternative is to move them as-is to the cloud.
  
  
• You need less-costly, more-scalable backup and recovery. Transitioning backups from on-premises to the cloud is a common use case in all but the most heavily regulated industries or for applications with the tightest RPOs/RTOs (recovery point objectives/recovery time objectives).

Before undertaking any lift and shift migration, carefully assess and prepare for factors that can impact the difficulty, cost, and ultimate value of the undertaking. These can include, but are not limited to the following:

1. Application lifespan: How much longer will you continue to use this application or run this workload? In most cases, it doesn’t make sense to migrate an application you’ll be retiring within the next 12 months.
   
   
2. API access restrictions: Make sure your move to the cloud won't result in bottlenecks for your current API tools.
   
   
3. Migration automation tools: Identify whether your cloud hosting provider offers any automated tools for migrations and plan to use them whenever possible.
   
   
4. Migration priority: If you’re planning to migrate multiple applications, create a runbook to ensure that mission-critical applications are migrated first (or whatever order that makes the most sense for your business).
   
   
5. Compliance: Before migrating from your private, on-premises environment to a private or public cloud, evaluate your migration plan and the cloud provider’s infrastructure to ensure all compliance requirements will be met during and after the migration.
   
   
6. Feature and scope creep: Feature-rich cloud environments can easily tempt you to integrate capabilities on the fly, leading to delays and resource drains. Have a clearly defined project and stick to it throughout the migration.