• AWS Transform MGN (formerly AWS Application Migration Service) is a dedicated rehosting capability that automates the conversion of your source servers (physical, virtual, or cloud) into native Amazon EC2 instances.

• It handles continuous block-level replication, automated machine conversion, and orchestrated cutover, enabling you to migrate workloads with minimal downtime and without modifying your source environment.

Note: AWS Application Migration Service (MGN) was rebranded to AWS Transform MGN in June 2026.

How It Works

• Install AWS Replication Agent on the source servers.

• If you use agentless replication for vCenter feature, you must add your source servers by installing the AWS MGN vCenter Client.

• Replicate source servers to AWS.

• Perform acceptance tests on servers.

• Execute a cutover instance.

Concepts

• Replication Settings

  • Determines how data will be replicated from source servers to AWS.

  • The Replication Settings template specifies how data replication will be implemented on each new server.

  • Replication servers (EC2 instances) are automatically launched and terminated as needed.

• The launch template controls how MGN launches instances in AWS.

• Post-launch Settings

  • To enable post-launch actions, you must allow MGN to install the SSM Agent on your servers.

  • You can configure the following to a post-launch settings template:

    • Automate target instance deployment.

    • Prepare the migrated servers for disaster recovery.

    • Convert operating system.

    • Change license and subscription.

• Source Servers

  • To migrate your servers into AWS, you’ll need to have a source server.

  • By installing AWS Replication Agent on each individual server, source servers will automatically be added to the AWS MGN.

  • Agentless snapshot replication 

    • Enables you to replicate source servers into AWS without installing an agent.

    • You can perform it from the vCenter source environment into AWS.

• Launch Settings

  • General launch settings – allows you to modify a number of server-specific settings

  • EC2 launch template – utilizes templates to launch test and cutover EC2 instances.

  • You can test or cutover: 

    • One source server at a time.

    • Multiple source servers simultaneously.

  • Instance type right sizing: Automatically launches a test or cutover instance type that best matches the OS, CPU, and RAM of your source server.
  • Start instance upon launch: Choose whether to start test and cutover instances automatically or launch them in a stopped state.
  • Copy private IP: Ensures the private IP used by the test or cutover instance matches the private IP used by the source server.
  • Transfer server tags: Transfers user-configured custom tags from source servers to test or cutover instances.
  • Operating system licensing: Choose Bring Your Own License (BYOL) or License Included (LI) for migrated instances.

• Launch history allows you to track and manage all operations performed.

Networking

• The data replicated from your source servers to AWS is located in the staging area subnet.

• Staging area subnet data is sent over TCP port 443 to the API endpoint:

  • https://mgn.{region}.amazonaws.com/. Replace “{region}”

• While the source server’s data is sent over TCP port 1500 to the staging area subnet.

• Instances for test and cutover are launched in the subnet specified in the EC2 Launch Template associated with each source server.

• The EC2 launch template is automatically created when you add a source server to AWS MGN.

• IPv6 support: MGN supports IPv6 for both service communication and application migrations in regions where Amazon EC2 dual-stack endpoints are present.

Monitoring

• Use CloudWatch to monitor AWS resources and applications in real time.

• You can also configure alarms to monitor specific thresholds and send notifications or take action when those thresholds are reached.

• With CloudTrail, you can log API calls and related events and send them to an S3 bucket.

• You can use EventBridge to send an event whenever a Source server launch is complete.

Security

• Use the global condition context keys in resource policies to limit the permissions granted by AWS MGN.

  • aws:SourceArn

  • aws :SourceAccount

• To install the AWS Replication Agent, you must first generate an AWS credentials:

  • Persistent IAM credentials

  • Non-persistent IAM credentials

• MGN retains all existing compliance certifications: FedRAMP High, HIPAA, PCI DSS, ISO, and SOC 1, 2, and 3.

Pricing

AWS Transform MGN pricing is based on:

• AWS infrastructure provisioned to facilitate data replication (staging area resources)
• Resources provisioned when you launch test or cutover instances
• Data transfer costs associated with replication

There are no upfront costs or termination fees. Pricing may vary by region.

For current pricing details, refer to the official AWS Transform MGN pricing page.

References

https://aws.amazon.com/application-migration-service/

https://docs.aws.amazon.com/mgn/latest/ug/what-is-mgn.html