SAP-C02 Study Guide: Selecting Workloads for Migration
Select existing workloads and processes for potential migration
Selecting Existing Workloads and Processes for Migration
This guide covers Task 4.1 of the AWS Certified Solutions Architect - Professional (SAP-C02) exam. It focuses on the strategic evaluation of an IT portfolio to determine which applications should move to the cloud, when they should move, and how they should be categorized using the AWS migration framework.
Learning Objectives
After studying this guide, you should be able to:
- Identify the core business drivers for cloud migration (Cost, Agility, Security, etc.).
- Execute a Portfolio Assessment and prioritize workloads using Wave Planning.
- Evaluate applications according to the 7 Rs migration strategies.
- Perform a Total Cost of Ownership (TCO) analysis to build a business case.
- Utilize AWS tools like AWS Migration Hub and Application Discovery Service for assessment.
Key Terms & Glossary
- TCO (Total Cost of Ownership): A financial estimate intended to help buyers and owners determine the direct and indirect costs of a product or system, including migration costs and operational spend.
- 7 Rs: The seven common migration strategies: Rehost, Replatform, Refactor, Rebuy, Relocate, Retain, and Retire.
- Landing Zone: A well-architected, multi-account AWS environment that is a starting point from which organizations can quickly launch and deploy workloads and applications.
- CMDB (Configuration Management Database): A repository that acts as a data warehouse, storing information about IT assets and their relationships.
- Wave Planning: The process of grouping applications into logical migration groups (waves) based on complexity and dependencies.
The "Big Idea"
Migration is not merely a "lift-and-shift" technical exercise; it is a business transformation. Selecting the right workloads involves balancing technical feasibility with business value. The goal is to create a repeatable process (the "Migration Factory") that reduces risk and accelerates time-to-value by starting with simple "low-hanging fruit" before tackling complex legacy monoliths.
Formula / Concept Box
| Concept | Description / Formula |
|---|---|
| TCO Calculation | TCO = (On-Premises\ Costs) - (AWS\ Operational\ Costs + Migration\ Costs) |
| Migration Effort | Higher for Refactor/Rearchitect; Lower for Rehost/Relocate |
| Mobilize Phase | Business Case + Application Discovery + Landing Zone + Security/Governance |
Visual Anchors
Migration Strategy Decision Tree
The Mobilize Phase Pillars
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Hierarchical Outline
- I. Drivers for Migration
- Cost Reduction: Shifting from CapEx (upfront) to OpEx (pay-as-you-go).
- Agility: Faster provisioning of resources (minutes vs. months).
- Security/Resiliency: Inheriting AWS compliance and managed security controls.
- End of Life (EoL): Retiring hardware or software that is no longer supported.
- II. The Mobilize Phase
- Detailed Business Case: Multi-year TCO projections (1, 3, 5 years).
- Application Discovery: Using tools like AWS Application Discovery Service to map dependencies.
- Governance: Setting up AWS Control Tower and AWS Organizations.
- III. Portfolio Assessment (The 7 Rs)
- Rehost: Moving applications without changes.
- Replatform: Upgrading components (e.g., moving DB to Amazon RDS) without core code changes.
- Refactor: Re-architecting to use cloud-native features (e.g., Lambda, S3).
- IV. Prioritization & Wave Planning
- First Wave: Simple, low-dependency apps to build confidence.
- Later Waves: Complex, business-critical monoliths with high dependencies.
Definition-Example Pairs
- Replatform (Lift and Reshape): Making minimal changes to achieve a benefit without changing core architecture.
- Example: Migrating an on-premises Oracle database to Amazon RDS for Oracle to offload patching and backups.
- Relocate: Moving a large number of VMs to a cloud-based VMware environment.
- Example: Moving workloads from on-premises VMware vSphere to VMware Cloud on AWS using HCX.
- Retire: Identifying assets that are no longer useful and can be turned off.
- Example: Finding a legacy reporting server that hasn't been accessed in 2 years and decommissioning it instead of migrating it.
Comparison Tables: The 7 Rs of Migration
| Strategy | Effort | Complexity | Business Value | Typical Use Case |
|---|---|---|---|---|
| Rehost | Low | Low | Medium | Quick "as-is" move; data center exit. |
| Replatform | Medium | Medium | High | Optimize DBs or OS without code rewrites. |
| Refactor | High | High | Very High | Modernizing to Serverless/Microservices. |
| Rebuy | Low | Low | High | Replacing custom HR app with SaaS (e.g., Workday). |
| Retain | N/A | N/A | N/A | Keeping legacy apps on-prem for compliance. |
Worked Example: Assessing a Legacy Java Application
Scenario: A company has a 10-year-old Java monolith running on a Windows Server 2012 (EoL) with a local SQL Server.
- Discovery: Use AWS Application Discovery Service (Agent-based) to track CPU/RAM usage and identify that it talks to an external LDAP server.
- TCO Analysis: Compare the cost of maintaining the aging physical server vs. an EC2 instance + RDS instance.
- Strategy Selection:
- Decision: The OS is EoL, so Rehost is risky.
- Action: Replatform. Move the code to a newer Windows version on EC2 and migrate the DB to Amazon RDS for SQL Server.
- Wave Planning: This app has high dependencies (LDAP). It should not be in Wave 1. It is scheduled for Wave 3 once the Landing Zone and Network (Direct Connect) are stable.
Checkpoint Questions
- Which migration strategy involves the highest amount of code modification but yields the highest ROI in terms of cloud-native features?
- What AWS service is specifically designed to create a governed multi-account environment as part of a Landing Zone?
- True/False: A "Retain" strategy means the application will eventually be moved to the cloud in its current state.
- What is the difference between Agentless and Agent-based discovery in the Application Discovery Service?
Muddy Points & Cross-Refs
- Confusion between Rehost and Replatform: Remember, Rehost is a mirror image (same OS, same DB engine on EC2). Replatform involves a change to a managed service (RDS) or a slight OS version upgrade to gain efficiency.
- Data Privacy in Discovery: Some stakeholders fear discovery tools collecting sensitive data. Cross-Ref: Review AWS IAM and encryption at rest/transit for discovery data.
- Wave Dependencies: Understanding that an app cannot migrate until its database or authentication provider (LDAP/AD) is available in the cloud. Cross-Ref: Domain 1.1 (Network Connectivity/Direct Connect).