A detailed architectural breakdown of migrating from AWS to GCP, aimed at CTOs and senior engineers. Covers the key differences in networking (regional AWS VPCs vs. global GCP VPCs), IAM models (flat AWS policies vs. GCP's hierarchical resource model), compute and Kubernetes (EKS vs. GKE), storage and databases (S3/RDS/DynamoDB vs. GCS/Cloud SQL/Firestore), and pricing (Sustained Use Discounts vs. Reserved Instances). Introduces a three-category framework for classifying workloads by cloud coupling, and outlines a six-phase migration sequence: assess, build GCP foundation, pilot, wave migration, gradual traffic shifting, and validation before decommissioning AWS. Also clarifies what doesn't change: application code, container strategy, IaC discipline, and observability philosophy.
