Mastering AWS Application Migration Tools

This study guide covers the essential tools and strategies for migrating application workloads to AWS, specifically focusing on the AWS Application Discovery Service (ADS) and the AWS Application Migration Service (MGN) as required for the SAP-C02 exam.

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Learning Objectives

After studying this module, you should be able to:

• Differentiate between agent-based and agentless discovery methods using AWS Application Discovery Service.
• Evaluate workloads according to the 7Rs migration strategy (Re-host, Re-platform, Refactor, etc.).
• Explain the architectural flow of data in AWS Application Migration Service (MGN).
• Apply security best practices, including encryption at rest and in transit, to migration workflows.
• Select the appropriate tool (MGN vs. VMC on AWS) based on source infrastructure and business requirements.

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Key Terms & Glossary

• AWS MGN (Application Migration Service): The primary service recommended for lift-and-shift (re-host) migrations to AWS.
• Agent-based Discovery: A method of collecting deep performance and dependency data by installing software directly on source servers.
• Block-level Replication: A data transfer method that copies disk blocks rather than individual files, ensuring byte-for-byte consistency.
• Staging Area VPC: A temporary environment in AWS where replication servers receive and write data to EBS volumes before the final cutover.
• 7Rs: A framework for categorizing migration strategies: Re-host, Re-platform, Refactor, Re-purchase, Retire, Retain, and Relocate.

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The "Big Idea"

Migration is not a single event but a lifecycle. It begins with Discovery (understanding what you have), moves to Assessment (deciding the strategy via the 7Rs), and concludes with Execution (using tools like MGN to move bits). The "Professional" level architect must ensure this lifecycle is secure, cost-effective, and causes minimal downtime by selecting the right orchestration tool for the specific source environment.

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Formula / Concept Box

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Hierarchical Outline

1. Phase 1: Discovery & Assessment
   • AWS Application Discovery Service (ADS)
     • Agentless: Uses a connector on VMware; identifies VM inventory.
     • Agent-based: Installed on OS; identifies processes and network dependencies.
   • AWS Migration Hub
     • Centralized dashboard to track migration progress across different tools.
2. Phase 2: Server Migration
   • AWS Application Migration Service (MGN)
     • Replaces SMS (Server Migration Service) and CloudEndure.
     • Continuous block-level replication.
   • VMware Cloud (VMC) on AWS
     • Specific for VMware-to-VMware "Relocate" strategy.
3. Phase 3: Security & Governance
   • Encryption in Transit: Secured via TLS 1.2.
   • Encryption at Rest: Managed via AWS KMS on Amazon EBS volumes.

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Visual Anchors

The Migration Workflow

MGN Architecture Detail

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Definition-Example Pairs

• Continuous Replication: The process of copying changes to the cloud in real-time as they happen at the source.
  • Example: An e-commerce database server on-premises constantly writes new orders; MGN captures these sub-second changes so the cloud version is always up-to-date for cutover.
• Test Mode: A state in MGN where a source server is launched in AWS for validation without stopping the original server.
  • Example: Launching a production web server in a test VPC to ensure the database connection strings work in the new network environment before the actual migration weekend.

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Worked Examples

Problem: Migrating a Legacy SQL Server

Scenario: A company has a 10TB SQL Server running on an old physical machine. They need to migrate it with less than 30 minutes of downtime.

Solution Steps:

1. Assessment: Use AWS Application Discovery Service (ADS) Agents to verify process dependencies (e.g., which apps talk to this SQL server).
2. Setup: Install the AWS MGN Replication Agent on the physical SQL server.
3. Replication: MGN begins a "Baseline" sync of the 10TB. This may take days, but the source remains live.
4. Continuous Sync: Once the baseline is done, MGN keeps the EBS volumes in the AWS Staging Area synced with new writes.
5. Cutover: During a maintenance window, stop the source SQL service, allow the final bits to sync (seconds), and trigger the "Cutover" launch in MGN. This converts the server into an EC2 instance.

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Checkpoint Questions

1. Which service is the successor to AWS SMS and CloudEndure for re-hosting servers?
2. What is the primary difference in data collection between the ADS Agentless and Agent-based discovery?
3. Why is a "Staging Area VPC" used in AWS MGN instead of launching directly into production?
4. Which migration strategy (from the 7Rs) applies specifically to moving VMs to VMware Cloud on AWS?

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Muddy Points & Cross-Refs

• MGN vs. DMS: Use MGN for full server migrations (OS + Apps + Data). Use DMS (Database Migration Service) if you are only moving the database and want to change the engine (e.g., SQL Server to Aurora).
• Agentless vs. Agent-based: Remember that Agentless discovery is fast but only sees metadata (CPU, RAM, Disk). Agent-based discovery is deep (it sees what software is installed and which network ports are active).
• Network Security: All MGN traffic from the agent to the replication instance uses Port 1500 for data and Port 443 for control. Ensure firewall rules are updated.

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Comparison Tables

Discovery Options

Server Migration Tools