Memory hook: Move what you have; modernize what creates value.
Must remember
Discover dependencies and business constraints before selecting a migration. Retain keeps a workload where it is; retire removes it; rehost moves it with limited change; replatform improves selected components; refactor changes application design. A large rewrite is not automatically the best first step under a tight deadline.
Compute Engine provides VMs and OS control. Containers package application dependencies; GKE manages Kubernetes orchestration. Cloud Run services execute request-driven containers, and Cloud Run functions supports function-oriented workloads. Serverless shifts infrastructure operation to the provider; code, data and scaling limits still need design.
Autoscaling changes capacity; load balancing distributes traffic. Microservices separate capabilities into independently operated components, which can improve delivery flexibility but add network, observability and consistency complexity. Spot VMs suit interruption-tolerant jobs, not an unprotected single critical server.
APIs expose defined capabilities to other software. Apigee helps govern, secure, analyze and monetize API programs. Hybrid/multicloud offerings such as GKE Enterprise, AlloyDB Omni or BigQuery Omni address particular deployment/data needs; confirm product support rather than assuming every managed service runs everywhere.
Choose under exam pressure
| Requirement | Choice and reason |
|---|---|
| Minimal change to a legacy OS-dependent app | Rehost on an appropriate VM. |
| Stateless web container with low administration | Cloud Run. |
| Govern partner/public APIs | Apigee API management. |
Traps
- Containers do not automatically make an application a microservice architecture.
- Serverless does not mean no cost or no limits.
Active recall
1. Rehost versus refactor?
Move with limited change versus redesign application internals.
2. What does a load balancer do?
Distributes eligible traffic among healthy backends.
3. Why avoid Spot for an unprotected critical singleton?
It can be interrupted and replacement capacity is not guaranteed.
4. What is an API contract?
The defined operations, inputs and outputs software exposes.
5. Why discover dependencies first?
Moving one component can break hidden network, data or identity relationships.