---
title: Rehost
description: Rehost migrates applications with minimal code change and prioritizes delivery speed, operational continuity, and predictable wave throughput.
sidebar:
  label: Rehost
  order: 2
source_url: "https://framework.stackit.cloud/migration/design-and-mobilize/design/rehost/"
source_file: "docs/migration/design-and-mobilize/design/rehost.mdx"
---

## Understanding Rehost

Rehost (lift-and-shift) migrates workloads with minimal application change. It is primarily a
run strategy to reduce transition risk and accelerate migration throughput.

In practical terms, Rehost is application-wave oriented: each workload gets a defined target runtime
mapping, cutover path, and runbook package for repeatable factory delivery.

## Rehost compared to Relocate in STACKIT

Relocate and Rehost are often used interchangeably, but in this framework they are separated on purpose.

- **Rehost in STACKIT**: Application-level lift-and-shift with explicit target runtime mapping, cutover,
  rollback, and runbook standardization.
- **Relocate in STACKIT**: Estate-level move of existing virtualization patterns with minimal reshaping of
  workload runtime behavior.
- **When to prefer Rehost**: When migration waves require repeatable runbooks and stable run operations at
  scale across many applications.
- **When to prefer Relocate**: When urgent movement of VM estates is the primary goal and modernization is
  deferred by design.

## When Rehost is a good fit

- **Strict migration timeline** with limited engineering capacity for redesign.
- **Legacy workloads** that are difficult to refactor in the current program phase.
- **Business stability priority** where functional behavior must remain largely unchanged.
- **Factory scale objective** where repeatable migration procedures are required across many systems.

## Design considerations in STACKIT context

<CardGrid>
  <Card title="Infrastructure mapping">
    Define target compute, storage, and network profiles with explicit compatibility checks.
  </Card>
  <Card title="Data and cutover path">
    Design transfer windows, consistency checks, and rollback triggers.
  </Card>
  <Card title="Stateful workload handling">
    Separate application artifact rollout from database migration sequencing to reduce cutover risk.
  </Card>
  <Card title="Security and compliance">
    Map identity controls, encryption requirements, and evidence checkpoints.
  </Card>
  <Card title="Operational handover">
    Ensure runbooks cover Day-1 operations and incident workflows after migration.
  </Card>
</CardGrid>

## Recommended design flow

<Steps>

1. Baseline current runtime dependencies and non-functional requirements.
2. Define target runtime mapping and migration sequence.
3. Design data movement and cutover orchestration.
4. Validate runbook quality with dry-run checkpoints.
5. Approve production migration with release and business sign-off.

</Steps>

## Data migration path in Rehost

In Rehost scenarios, the data migration path depends on whether the workload is stateless or stateful:

- **Stateless workloads**: Focus on application deployment and configuration.
- **Stateful workloads**: Require a coordinated data movement strategy alongside the application migration.

For stateful migration waves, split the path into two streams:

1. **Infrastructure and application stream**: Provision the target environment, deploy the application, and prepare the target data store.
2. **Data stream**: Export source data, transfer to the target, restore, and validate.

### Suggested data sequence

1. Export data from the source system using platform-native or tool-specific methods.
2. Transfer data to the target environment or intermediate staging area.
3. Configure the target environment to ingest the migrated data.
4. Run the restoration process and verify data integrity.
5. Validate application connectivity and functional behavior before final cutover.

## Required outputs

### Shared outputs across all migration paths

- Approved design decision record with scope, assumptions, and governance sign-off.
- Validation evidence package for security, compliance, and operational readiness.
- Strategy-specific migration runbook draft from the Design phase.
- Handover package for Migration Factory Setup and wave planning.

### Rehost-specific outputs

- Rehost decision rationale and constraints.
- Target runtime mapping.
- Data movement and cutover plan.
- Runbook with validation and rollback checkpoints.
- Post-wave stabilization checklist.

## Diagram step reference

### Define landing zone

Define landing zone requirements and controls as the start point for Rehost run.
Clarify network, identity, backup, and monitoring prerequisites before migration sequencing is
approved so Rehost waves can run with predictable operations quality.

- <LinkChip href="/migration/design-and-mobilize/landing-zones/overview/">Landing Zones Overview</LinkChip>
- <LinkChip href="/migration/design-and-mobilize/landing-zones/application-landing-zone/">Application Landing Zone</LinkChip>
- <LinkChip href="/migration/design-and-mobilize/design/cloud-design-patterns/">Cloud Design Patterns</LinkChip>

### Use migration tools

Define the automated Rehost path used for repeatable wave throughput.
In the automated Rehost path, infrastructure and application setup are provisioned as code so
wave delivery stays repeatable and auditable.

- **Provision VM target with IaC**: Create networks, security groups, compute instances, and base storage through Terraform or OpenTofu.
- **Install and configure application with automation**: Use Ansible playbooks for package install, service setup, and baseline configuration.
- **Apply environment-specific parameters**: Inject target variables, secrets references, and endpoint mappings in a controlled automation run.
- **Run automated validation and cutover gates**: Execute health checks, migration pre-checks, rollback checkpoints, and release approvals before live switch.

- <LinkChip href="/migration/design-and-mobilize/design/runbook/">Runbook Blueprint</LinkChip>
- <LinkChip href="/migration/design-and-mobilize/migration-plan/overview/">Migration Plan</LinkChip>

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The runbook asset documents the PostgreSQL flags and the optional dump-based data restore path.

### Install

Describe manual installation steps for exception workloads.

- **Create and prepare target VM manually**: Provision the VM through Portal or CLI, attach required storage, and apply OS hardening and patch baseline.
- **Install runtime and dependencies manually**: Install required runtime packages, system libraries, and service users/groups according to product installation guidance.
- **Install application in the classic way**: Perform guided installation steps (for example installer or setup wizard flow) to reproduce the source deployment model on the target VM.
- **Validate base install readiness**: Confirm service startup, file permissions, required ports, DNS reachability, and outbound connectivity.

- <LinkChip href="/migration/design-and-mobilize/design/cloud-design-patterns/">Cloud Design Patterns</LinkChip>
- <LinkChip href="/migration/design-and-mobilize/design/runbook/">Runbook Blueprint</LinkChip>

### Config

Define manual runtime configuration and controls.

- **Mirror source configuration for target context**: Recreate application settings from the source environment and adapt them to target endpoints, DNS, certificates, and service integrations.
- **Apply security and access settings**: Configure service credentials, secret handling, and least-privilege access for target operation.
- **Align operational defaults**: Configure logging targets, metrics exporters, backup schedules, and retention baselines.
- **Validate configuration parity**: Run smoke checks to confirm the target instance behaves as a functional equivalent of the source baseline.

- <LinkChip href="/migration/design-and-mobilize/design/runbook/">Runbook Blueprint</LinkChip>

### Deploy

Define manual deployment sequencing and release checks.

- **Plan final migration window**: Align freeze windows, communication checkpoints, and rollback authority for production switch.
- **Run final data migration**: Execute last data sync or restore steps and confirm consistency checks before go-live.
- **Activate production traffic**: Perform controlled live switch to the target environment and verify critical user and integration paths.
- **Confirm handover readiness**: Record evidence, close open risks, and transfer ownership for Day-1 operations.

- <LinkChip href="/migration/design-and-mobilize/migration-plan/overview/">Migration Plan</LinkChip>
- <LinkChip href="/migration/design-and-mobilize/design/runbook/">Runbook Blueprint</LinkChip>