AWS Application Migration Service
A service for lift-and-shift migration of on-premises or other cloud servers to AWS, minimizing cutover downtime through continuous replication
Overview
AWS Application Migration Service (MGN) is a service for migrating physical servers, virtual machines, and other cloud instances to AWS as EC2 instances. Installing an agent on the source server initiates block-level continuous replication, enabling migration to AWS without any changes to the OS or applications. The two-stage process of test launch and cutover allows safe pre-production verification before the actual switchover.
Agent-Based Block Replication Enabling Near-Zero Downtime Migration
AWS's product page gives AWS Transform MGN as the current name of AWS Application Migration Service (as of October 2026). The MGN migration process begins with installing the AWS Replication Agent on the source server. The agent detects changes at the disk block level and continuously replicates them to a staging area on the AWS side (lightweight EC2 instances and EBS volumes). After the initial full sync completes, only deltas are transferred, limiting the impact on network bandwidth. During this continuous replication, the source server keeps running normally while the replica on AWS is continuously updated. At cutover, you launch production EC2 instances from the replica and switch DNS or load balancers. Azure Migrate also offers similar agent-based migration.
Two-Stage Process of Test Launch and Cutover
To ensure migration reliability, MGN clearly separates the Test and Cutover stages. During test launch, EC2 instances are started from replicated data to perform application verification, network connectivity testing, and performance validation. Test instances launch in an environment independent of production, so they do not affect source server operations. Once testing succeeds, you execute the cutover to launch production instances. Pre-defining instance type, subnet, security group, and IAM role in launch templates reduces manual configuration during cutover. If issues arise with the cutover instances, the user guide describes reverting the cutover, which reverts the source servers' migration lifecycle status to Ready for cutover.
Large-Scale Migration Wave Planning and Migration Hub Integration
For migrations involving hundreds of servers, one approach divides migration targets into waves, grouping servers with dependencies into the same wave. MGN supports grouping servers by wave and application concepts, enabling batch test launches and cutovers at the wave level. Integration with Migration Hub automatically reflects MGN migration progress on the Migration Hub dashboard, providing a unified view of overall progress alongside DMS database migrations. AWS states that Migration Hub stopped accepting new customers as of November 7, 2025, and continues to operate for existing customers to complete their ongoing migration projects. In the pre-migration discovery phase, Migration Hub's Application Discovery Service or Agentless Collector collects server configurations, dependencies, and performance data from the on-premises environment as foundational data for migration planning. The official pricing page states that MGN itself is free for an initial period of replication for each server and is then charged by the hour, while AWS resources used during migration, such as EC2 instances and EBS volumes, are charged separately (as of October 2026). The user guide states that the replication servers in the staging area use the t3.small instance type by default.
References (Official AWS Resources)
The primary sources for this page are the official AWS website and documentation. Check the official pages below for the latest specifications and pricing.
- AWS Migration Hub official page
- Amazon EC2 official page
- Amazon EBS official page
- AWS Documentation (official)
If this page and the official documentation disagree, treat the official documentation as authoritative.