AWS Solutions Architect · Lesson

AWS Migration Hub and Application Discovery Service

Inventory on-premises servers with Application Discovery Service agents and track migration progress across tools in Migration Hub.

AWS Migration Hub and Application Discovery Service is a free AWS Solutions Architect lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the AWS Solutions Architect learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

The Challenge of Portfolio Migration

Migrating hundreds or thousands of applications to AWS requires a systematic approach. You need to know what you have on-premises, how applications depend on each other, and what resource utilisation looks like before sizing AWS equivalents. AWS Migration Hub and Application Discovery Service form the assessment layer of the AWS migration toolkit, providing visibility and tracking across the entire portfolio.

AWS Migration Hub Overview

AWS Migration Hub is a central dashboard for tracking the progress of application migrations across multiple AWS migration tools (MGN, DMS, and partners). It aggregates migration status in a single console so project managers and architects can see which servers are discovered, being replicated, tested, or cut over. Migration Hub is a free tracking service — you pay only for the underlying migration tools you use.

# List migration tasks in Migration Hub via CLI
aws migrationhub list-migration-tasks \
  --filter-value 'NOT_STARTED,IN_PROGRESS,COMPLETED'

Application Discovery Service: Agent vs Agentless

Application Discovery Service (ADS) collects data about on-premises servers and their dependencies before migration. It has two discovery modes: Agent-based (installs a lightweight agent on each server to capture CPU, memory, network I/O, running processes, and network connections) and Agentless (uses a VMware vCenter connector to gather VM configuration and performance metrics without touching individual VMs).

# Agent-based: Install ADS agent on a Linux server
# Download installer from AWS console, then:
sudo bash ./aws-discovery-agent.sh -k <AWS_KEY_ID> \
  -s <AWS_SECRET_KEY> -r us-east-1

# Verify agent is running
sudo service aws-discovery-daemon status

Discovering Network Dependencies

One of the most valuable ADS capabilities is mapping network dependency graphs. The ADS agent captures TCP connections between processes, revealing which databases, microservices, or middleware components each application communicates with. This prevents the common migration failure of moving an application without its dependencies, which then causes production outages due to missing connections across network boundaries.

# Export discovered network connections to S3 for analysis
aws discovery start-export-task \
  --export-data-format 'CSV'

# List completed export tasks
aws discovery describe-export-tasks

Importing Data from Third-Party Tools

Many enterprises already have CMDB (Configuration Management Database) or discovery data from tools like ServiceNow, Dynatrace, or Ansible. Migration Hub supports import templates — standardised CSV files that let you upload existing server inventory data directly without deploying ADS agents. This is useful for quick assessment phases where agent installation is not immediately feasible due to security or access restrictions.

# Import servers from a CSV template
aws migrationhubstrategy start-import-file-task \
  --name 'vmware-inventory' \
  --s3-bucket-for-report-data 'my-migration-bucket' \
  --s3-url 's3://my-migration-bucket/imports/server-inventory.csv'

Migration Hub Strategy Recommendations

Migration Hub Strategy Recommendations analyses collected ADS data along with your application's running workloads and recommends one of the 7 Rs for each server or application. It can identify applications suitable for containerisation, flag servers running unsupported OS versions that need refactoring, and suggest target AWS services. The service integrates with the AWS Well-Architected Framework to align recommendations with best practices.

Grouping Servers into Applications

After discovery, ADS data appears as individual servers. In Migration Hub you group related servers into applications that represent a business capability (e.g., the 'Order Management System' might include a web tier, app tier, and database server). Groups can be created manually or derived from ADS network dependency maps. Grouping is essential for tracking migration progress at the application level rather than the server level.

# Create an application group in Migration Hub
aws migrationhub create-progress-update-stream \
  --progress-update-stream-name 'OrderManagementSystem'

# Associate a discovered server with an application
aws migrationhub associate-discovered-resource \
  --progress-update-stream-name 'OrderManagementSystem' \
  --migration-task-name 'Rehost-WebTier' \
  --discovered-resource '{"ConfigurationId": "d-server-01234", "Description": "Web Server 1"}'

Integrating with MGN and DMS

Migration Hub integrates natively with AWS Application Migration Service (MGN) and Database Migration Service (DMS). Once MGN begins replicating a server, it automatically reports replication progress back to Migration Hub. Similarly, DMS migration tasks update their status in Migration Hub. This integration gives a consolidated view without requiring manual updates, and you can drill from the Hub into the native tool console for details.

Migration Hub Refactor Spaces

Migration Hub Refactor Spaces helps teams incrementally refactor monolithic applications into microservices. It creates an AWS environment (a VPC-based overlay) with a unified ingress point (an API Gateway or Application Load Balancer). Traffic routing rules send a subset of requests to new microservices while the rest still go to the existing monolith — the strangler fig pattern in managed form, without writing custom traffic routing code.

TCO Analysis and Rightsizing

After ADS collects utilisation data (CPU, memory, disk I/O over several weeks), use the AWS Migration Evaluator (formerly TSO Logic) to generate a Total Cost of Ownership (TCO) analysis. It compares current on-premises costs (hardware, power, cooling, labour) with projected AWS costs using right-sized instances. This business case is typically presented to executives to justify the migration investment and quantify cloud savings.

ADS Data in Athena

ADS exports discovered data as CSV to S3 in a standard format. You can load this data into Athena to query utilisation patterns across your entire on-premises fleet — for example, finding all servers using less than 10% average CPU (Retire candidates) or all servers running EOL operating systems (Refactor candidates). This SQL-driven approach to portfolio analysis scales to thousands of servers without manual spreadsheet work.

-- Find underutilised servers (CPU < 10%) that are Retire candidates
SELECT hostName, avgCpuUsagePct, peakRamUsageMb
FROM ads_exports.server_utilization
WHERE avgCpuUsagePct < 10
  AND discoveryAgentStatus = 'ACTIVE'
ORDER BY avgCpuUsagePct ASC;

Quick Check

Test your understanding of AWS Solutions Architect (SAA-C03) concepts from this lesson.

Lesson Recap

In this lesson you learned: Migration Hub provides a central dashboard to track migration progress across MGN, DMS, and partner tools, Application Discovery Service offers agent-based and agentless modes to inventory on-premises servers and map dependencies, and Migration Hub Refactor Spaces supports incremental strangler-fig refactoring of monoliths. Next up we explore Application Migration Service (MGN) for the actual server replication.

Frequently asked questions

Is the “AWS Migration Hub and Application Discovery Service” lesson free?

Yes — the full text of “AWS Migration Hub and Application Discovery Service” is free to read here on the web, and the AWS Solutions Architect course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the AWS Solutions Architect course, upgrade to CoddyKit PRO.

What will I learn in “AWS Migration Hub and Application Discovery Service”?

Inventory on-premises servers with Application Discovery Service agents and track migration progress across tools in Migration Hub. You practise AWS Solutions Architect with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start AWS Solutions Architect?

No prior experience is required. AWS Solutions Architect on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “AWS Migration Hub and Application Discovery Service” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this AWS Solutions Architect lesson?

Yes. Every AWS Solutions Architect lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

The 7 Rs of Migration Strategy
AWS Migration Hub and Application Discovery Service
Application Migration Service (MGN)
Database Migration Service (DMS) and Schema Conversion Tool

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