AWS Application Migration Service (MGN) | Overview.

AWS Application Migration Service (MGN) - Overview.

Scope:

• Intro,
• Core Purpose of AWS MGN (Lift-and-shift any server),
• How AWS MGN Works (End-to-End Workflow),
• Key Components of AWS MGN,
• Advanced Features,
• Security & Compliance,
• Supported Operating Systems,
• Common Migration Patterns Enabled by MGN,
• Typical Architecture Diagram for AWS MGN,
• When to Use AWS MGN,
• AWS MGN vs Other AWS Migration Services,
• Key Takeaway.

Intro:

• AWS Application Migration Service (MGN) is Amazon’s flagship service for:
• Reliable, 
• Automated, 
• Scalable server migrations to AWS.
• AWS Application Migration Service (MGN) replaces AWS Server Migration Service (SMS) and Application Discovery Service (migration components).
•  MGN enables twtech to:
• Replicate its source servers continuously into AWS, 
• Run non-disruptive tests, 
• Perform orchestrated cutovers, 
• Minimize downtime during migration.
•  AWS Application Migration Service (MGN) is the primary AWS service for lift-and-shift migrations of:

•  Physical servers,
•  Virtual servers,
•  Cloud-based servers into AWS.

1. Core Purpose of AWS MGN (Lift-and-shift any server)

• Physical, VMware, Hyper-V, Azure, GCP, or other cloud VMs.
•  Convert servers into AWS-native EC2 instances
• Automatic OS conversion + driver injection + network configuration.
•  Reduce downtime
• Continuous block-level replication + short cutovers.
•  Simplify large-scale migrations
• hundreds/thousands of servers with grouping and automation.

2. How AWS MGN Works (End-to-End Workflow)

Step 1: Install AWS Replication Agent on Source Servers

• twtech installs a lightweight agent on each server. This starts block-level replication to AWS.

Step 2: Continuous Replication to Staging Area

MGN replicates data to an AWS Staging Area Subnet, which includes:

•  Replication Servers
•  EBS volumes represent replicated disks
•  The Replication Server manages compression, encryption, and snapshotting

NB:

• This staging area is fully automated by MGN.

Step 3: Launch Templates & Conversion Pipeline

• MGN prepares auto-generated EC2 Launch Templates for test & cutover instances:
•  OS conversion (Windows/Linux)
•  Boot loader updates
•  Network interface mapping
•  Storage mapping (EBS)
•  Driver injection (e.g., NVMe, ENA)
•  Initialization scripts

NB:

• twtech can override these templates with its own customization.

Step 4: Non-Disruptive Test Launch

twtech can launch test EC2 instances to validate:

•  Application behaviour
•  Network configuration
•  Security groups, IAM roles
•  Performance

NB:

• Testing does not affect the source server.

Step 5: Cutover Launch

After test validation, twtech schedules a cutover:

     1.     Replication catches up (final sync)
2.     Failover executes
3.     EC2 servers are launched
4.     Traffic is redirected (Route53, LB, IP mapping, etc.)

Step 6: Cleanup & Optimization

AWS MGN allows twtech to:

•  Decommission replication servers
•  Disable agents
•  Optimize resources (compute optimizer)
•  Implement post-migration modernization

3. Key Components of AWS MGN

 Source Servers

• The on-prem or cloud servers that twtech plans to migrate.

 Replication Agent

• Installed manually or deployed via automation.

 Staging Area Subnet

AWS-managed infrastructure:

•  Replication servers
•  Temporary EBS volumes
•  Networking (security groups, ENI)

 EC2 Conversion Templates

• Templates for test and cutover servers.

 AWS MGN Console

Manage migration lifecycle:

•  Replication health
•  Test launches
•  Cutover scheduling
•  Groups & Waves for large migrations

4. Advanced Features

Wave & Group Management

Organize migrations by:

•  Application
•  Environment (Prod, Dev)
•  Business Unit
•  Priority

Supports dependency mapping for sequencing.

 Automated Post-Migration Actions

AWS MGN integrates with AWS Systems Manager for:

• Registering instance to SSM
• Installing CloudWatch agents
• Installing security agents (e.g., CrowdStrike)
• Running healing scripts
• Tag enforcement

 Orchestration Using Migration Factory Solutions

AWS provides open-source automation frameworks:

•  Migration Factory
•  CloudEndure automation extensions

 Cross-account & Cross-Region Replication

twtech can replicate servers into:

•  Another region (DR)
•  Another AWS account (security boundary)

 Continuous Data Protection (CDP)

• MGN supports near-real-time replication with compression & encryption.

5. Security and Compliance

MGN is designed for secure enterprise migrations:

• All data encrypted in transit (TLS)
• All replicated data stored on encrypted EBS volumes
• IAM policies control migration access
• VPC isolation for staging areas

6. Supported Operating Systems

Windows

• 2008 R2 → 2022 (with caveats)
• AD, Exchange, .NET workloads supported

Linux

• RHEL, CentOS, Rocky, Ubuntu, SUSE, Debian
• Custom kernels supported with bootloader adjustments

7. Common Migration Patterns Enabled by MGN

 Lift-and-Shift (Rehost)

• Simplest, fastest, using EC2 conversion.

 Replatform with Post-Processing

Replace:

• SQL Server → RDS SQL
• Oracle → RDS Oracle
• Web Servers → ALB/ECS/EKS

 Disaster Recovery Architecture

• MGN can be used for DR failover, not just migration.

8. Typical Architecture Diagram for AWS MGN

9. When to Use AWS MGN

Use it when:

•  twtech wants low downtime
•  twtech needs to migrate legacy systems
•  twtech doesn't want to manually rebuild servers
•  Large-scale migration (1000+ servers)

Not ideal when:

• twtech is modernizing directly to containers/serverless
• Application rearchitecture is required
• Database engines are changing (Oracle → PostgreSQL)

10. AWS MGN vs Other AWS Migration Services

Service	Best For	Notes
MGN	Lift-and-shift servers	Most automated
SMS (deprecated)	Legacy tool	Replaced by MGN
DMS	Database migrations	Schema + data replication
ADS	Discovery & inventory	Not for replication
Migration Hub	Multi-service orchestration	Works with MGN/DMS

Key Takeaway

• AWS MGN is the preferred enterprise migration engine for moving servers to AWS. It provides:
• Continuous block-level replication
• Test launches without downtime
•  Automated server conversion
• Wave-based orchestration
• Secure and scalable migrations

NB:

• It's the fastest way to migrate workloads with minimal changes & minimal risk.