AWS Migration Phases and Services

🌐 Why Migrate to AWS?

Before diving into the technical phases, it’s important to understand why organizations choose to migrate workloads from on-premises data centers to AWS. The key drivers are:

1. 🚀 Accelerate Digital Transformation

Migrating to AWS enables organizations to modernize legacy applications, adopt cloud-native architectures, and leverage advanced services (AI/ML, analytics, serverless) to transform business processes faster. Instead of being held back by legacy infrastructure, teams can focus on innovation.

2. 🌀 Increase Agility

The cloud allows for rapid experimentation and scaling, enabling development teams to provision infrastructure in minutes instead of weeks. This agility accelerates product development cycles, improves time-to-market, and makes it easier to respond to changing business demands.

3. 💰 Reduce Operating Costs

By moving from capital expenditure (CapEx) models to operational expenditure (OpEx), organizations can pay only for what they use. AWS’s managed services reduce maintenance overhead, data center footprint, and energy costs. Rightsizing and on-demand provisioning further optimize costs.

4. 🌍 Leverage Cloud Scale and Performance

AWS offers virtually unlimited scalability across compute, storage, and networking, backed by a global infrastructure with low-latency connectivity. Workloads can scale elastically to meet demand peaks and take advantage of AWS’s optimized performance and availability zones.

5. 🛡️ Improve Security Posture and Compliance

AWS provides a shared responsibility model where AWS secures the infrastructure, and customers secure their workloads. Built-in security services, encryption, monitoring, and compliance certifications help organizations achieve higher security standards and meet regulatory requirements more effectively than many on-prem setups.

🧭 1. Assess Phase

Goal: Establish a clear understanding of your current environment—assets, dependencies, readiness—and build a migration strategy.

1.1 Inventory of Data Center Assets using Agent-Based Tools (CloudWatch + Systems Manager)

Purpose: Create a comprehensive inventory of your on-premises infrastructure—servers, applications, OS versions, installed software, and performance characteristics.

• AWS Systems Manager (SSM): Deploy the SSM Agent, register servers as hybrid activations, collect metadata and software inventory.
• Amazon CloudWatch Agent: Collects performance metrics (CPU, memory, I/O, network) and pushes them to CloudWatch for analysis.

1.2 AWS Application Discovery Service (ADS)

Purpose: Automate discovery of workloads and map interdependencies between applications.

• Deploy Discovery Agents or agentless connectors.
• Collect configuration, process, and network traffic data.
• Build application dependency maps to group workloads intelligently.

1.3 Migration Portfolio Assessment (MPA)

Purpose: Analyze, classify, and prioritize discovered workloads for migration at scale.

• Imports data from ADS or CMDBs.
• Classifies workloads using 6R strategies.
• Identifies blockers, estimates TCO, scores workloads by business value and complexity.

🏗️ 2. Mobilize Phase

Goal: Build the foundational AWS environment—a secure, scalable Landing Zone—to enable large-scale migrations.

2.1 AWS Control Tower

Purpose: Quickly set up a multi-account AWS environment that adheres to AWS best practices.

• Automates landing zone creation with management, log archive, and audit accounts.
• Applies guardrails (SCPs + AWS Config) for governance and compliance.
• Provides Account Factory for standardized account creation.

2.2 AWS Service Catalog

Purpose: Provide controlled self-service provisioning of standardized AWS resources.

• Define portfolios of pre-approved templates (EC2, RDS, VPCs, etc.).
• Enable application owners to provision resources without elevated permissions.
• Enforce compliance and consistency across accounts.

🚀 3. Migrate Phase

Goal: Move applications and data to AWS using appropriate migration services and patterns.

3.1 AWS Application Migration Service (MGN)

Purpose: Automate lift-and-shift migration of servers from physical, virtual, or other cloud environments to AWS.

• Install the Replication Agent on source servers.
• Continuous block-level replication to AWS.
• Test launches before cutover with minimal downtime.
• Supports post-migration automation.

3.2 AWS Database Migration Service (DMS)

Purpose: Migrate databases with minimal downtime.

• Set up replication tasks between source and target (RDS, Aurora, etc.).
• Perform full load and continuous replication (CDC).
• Use Schema Conversion Tool (SCT) for heterogeneous migrations.

✅ Summary Table