Mastering AWS Application Migration: A Closer Look at AWS MGN

In our previous discussion on AWS migration services, we explored AWS Application Discovery Service and several other vital tools that help businesses transition to the cloud with ease. In this continuation, we dive deeper into the AWS Application Migration Service, known as AWS MGN (Migration Hub).

What is AWS MGN (Migration Hub)?

AWS MGN, short for AWS Migration Hub, is an automated lift-and-shift solution that simplifies, expedites, and lowers the cost of migrating applications to AWS. Its primary objective is to convert source servers to run natively on AWS, making it an essential part of your migration strategy.

How AWS MGN Works

AWS MGN follows a structured workflow that is designed to ensure a seamless migration process. Here are the key steps:

  1. Install AWS Replication Agent: To get started, you need to install the AWS Replication Agent on the source servers in your on-premises environment. This agent is responsible for capturing the necessary system configuration, system performance, running processes, and network connection details.
  2. Replicate Source Servers to AWS: AWS MGN’s primary function is to replicate the source servers from your on-premises environment to AWS. This ensures that all the necessary data and configurations are transferred.
  3. Perform Acceptance Tests: Before proceeding further, you should conduct acceptance tests on the replicated servers to validate that everything works as expected. This step is crucial in ensuring that your applications are ready for production.
  4. Execute a Cutover Instance: The final step involves executing a cutover instance, which essentially marks the completion of the migration process. This cutover instance replaces your source servers in the AWS environment and takes over their workload.

Key Concepts in AWS MGN

  • Replication Settings: These settings determine how data will be replicated from source servers to AWS. A template specifies how data replication will be implemented on each new server, and replication servers (EC2 instances) are automatically launched and terminated as needed.
  • Post-launch Settings: These settings enable post-launch actions, allowing you to automate target instance deployment, prepare migrated servers for disaster recovery, convert the operating system, and change licenses and subscriptions.
  • Source Servers: To migrate your servers into AWS, you’ll need to install the AWS Replication Agent on each individual server. The source servers are then automatically added to AWS MGN. Additionally, AWS MGN offers agentless snapshot replication, which allows you to replicate source servers into AWS without installing an agent.
  • Launch Settings: These settings encompass general launch settings, which enable you to modify various server-specific configurations, and EC2 launch templates, which are utilized to launch test and cutover EC2 instances. You can perform tests or cutovers on one source server at a time or multiple source servers simultaneously.
  • Launch History: This feature allows you to track and manage all operations performed during the migration process.

Networking in AWS MGN

Data replicated from source servers to AWS is temporarily stored in the staging area subnet. This data is sent over TCP port 443 to the AWS MGN API endpoint. Source server data is sent over TCP port 1500 to the staging area subnet. Test and cutover instances are launched in the subnet specified in the EC2 Launch Template associated with each source server. AWS MGN automatically creates the EC2 launch template when you add a source server to AWS MGN.

Monitoring and Security

AWS MGN is equipped with robust monitoring capabilities through Amazon CloudWatch. You can monitor AWS resources and applications in real-time and configure alarms to take action when specific thresholds are reached. Additionally, AWS CloudTrail allows you to log API calls and related events, sending them to an S3 bucket. EventBridge can be used to trigger events upon source server launch completion.

In terms of security, AWS MGN employs global condition context keys in resource policies to limit the permissions granted by AWS MGN. These context keys include “aws:SourceArn” and “aws:SourceAccount.”

To install the AWS Replication Agent, you must generate AWS credentials, which can be either persistent IAM credentials or non-persistent IAM credentials.


When using AWS MGN, you’ll be charged for any AWS infrastructure provisioned to facilitate data replication and resources provisioned when you launch test or cutover instances. It’s important to review the pricing details carefully to understand the cost implications.

In conclusion, AWS MGN is a powerful tool that streamlines the application migration process to AWS. Its automation and replication capabilities, coupled with its monitoring and security features, make it an invaluable resource for businesses seeking a smooth and efficient migration journey. By understanding the inner workings of AWS MGN and its associated concepts, you can confidently plan and execute your migration projects. For more information, you can explore the official AWS Application Migration Service page and the AWS MGN documentation.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top