A Guide to Migrating Applications with AWS Application Migration Service

Overview

In today’s fast-paced digital landscape, businesses constantly seek ways to modernize and optimize their IT infrastructure. Migrating applications from on-premises environments to the cloud has become a common strategy for organizations looking to enhance scalability, improve cost efficiency, and ensure business continuity. Among the various tools available, AWS Application Migration Service (AWS MGN) stands out as a reliable and flexible solution for rehosting workloads on Amazon Web Services (AWS) with minimal downtime.

This blog will walk you through the end-to-end process of using AWS MGN, from configuring replication settings to testing and performing cutover migrations, so you can execute your migration journey confidently and smoothly.

AWS Application Migration Service

The service is designed for rehosting (lift-and-shift) migrations but also sets the stage for modernization after migrating workloads. Instead of rebuilding or re-architecting your applications, AWS MGN provides a straightforward path to migrate them as-is while minimizing downtime.

Getting Started with AWS MGN

Step 1: Create the Replication Template

First, log in to the AWS MGN Console and click on Get Started. This will take you to the replication template creation process.

The replication template defines default replication settings that will be applied to any new source server you add. These settings include key details like replication servers, disks to be replicated, staging area subnet, and encryption preferences.

Step 2: Install the AWS Replication Agent

You must install the AWS Replication Agent on each server to bring your on-premises or source servers into AWS MGN. This lightweight agent handles replicating server data to AWS in real time.

Here’s how to install it on a Linux server:

1. Download the Installer Script
   Use the wget command to download the aws-replication-installer-init.py file directly onto your source server.

2. Run the Installer
Execute the installation script, which will install and configure the agent.

Once the agent is successfully installed, the server will automatically appear in the AWS MGN console. At this point, the initial sync process begins, during which AWS MGN replicates the server disks and data to your AWS staging area.

Step 3: Configure Launch Settings

After replication is set up, the next critical step is configuring launch settings. These settings define how test or cutover instances of your source servers will be launched in AWS.

Launch settings include parameters such as:

• Instance type (size, family, vCPU, memory)
• Amazon Machine Image (AMI) options
• Security groups
• Subnets and Amazon VPC configurations
• Licensing settings (e.g., bring-your-own-license or AWS-provided licenses)

To configure launch settings:

1. Go to the Source Servers page in the AWS MGN console.

2. Click on the hostname of the server you want to configure.

3. Navigate to the Launch settings tab.

4. Adjust the parameters according to your workload requirements.

By configuring these settings, you ensure that when test or cutover instances are launched, they closely match your target production environment.

Step 4: Launch Test Instances

Testing is a crucial part of any migration strategy. Before moving to a cutover, you should launch test instances of your source servers to validate that everything functions correctly in AWS.

To launch test instances:

1. On the Source Servers page, select the checkbox next to the server(s) you want to test.
2. Choose Launch test instances.

3. Confirm by clicking Launch.

You can test a single server or multiple servers simultaneously. The AWS MGN console provides detailed status updates on whether each test launch succeeds or fails.

The goal of the test phase is to verify that:

• Applications run as expected
• Network configurations are correct
• Security groups and AWS IAM roles are properly applied
• Performance matches your expectations

If any issues arise, you can adjust replication or launch settings and relaunch the test until satisfied.

Step 5: Perform Cutover Migration

Once testing is complete and you’re confident in the environment, you can proceed with the cutover migration. The cutover instance represents your production workload running in AWS.

The process is like launching a test instance:

1. Select the servers you’re ready to migrate.
2. Choose Launch cutover instances.
3. Confirm by clicking Launch.

At this stage, your source servers are officially replaced by AWS-hosted instances. You can then decommission or repurpose your on-premises infrastructure.

Step 6: Monitor with the Migration Dashboard

AWS MGN provides a Migration Dashboard that helps you track the progress of your migration lifecycle. You can monitor statuses, review logs, and troubleshoot errors from replication to testing and cutover.

The dashboard offers a centralized view, ensuring transparency and control over the entire process.

Best Practices for Using AWS MGN

1. Plan Thoroughly
   Document your source servers, dependencies, and network requirements before migrating.
2. Start Small
   Begin with a few servers to test the process and refine your approach before scaling up to large workloads.
3. Leverage AWS Monitoring Tools
   Integrate with Amazon CloudWatch and AWS CloudTrail to gain additional visibility into replication and migration events.
4. Ensure Security
   Use encryption for replicated data and configure security groups and AWS IAM roles according to AWS best practices.

Conclusion

Migrating workloads to the cloud doesn’t have to be complex or disruptive. With AWS Application Migration Service, businesses can streamline the migration process, reduce manual effort, and confidently move to AWS.

Drop a query if you have any questions regarding AWS Application Migration Service and we will get back to you quickly.

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