Cloud Digital Leader Fundamental Cloud Concepts Practice Question
A company is migrating a legacy monolithic application to Google Cloud. The application currently runs on a single physical server with a custom Linux distribution. The team wants to minimize changes to the application while gaining the benefits of cloud infrastructure. Which migration strategy should they use?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Rehost the application on Compute Engine using a custom image of the current OS
Lift and shift (rehosting) moves the application as-is to the cloud, often by creating a custom image to run on Compute Engine. This minimizes changes. Refactoring (rearchitecting) involves code changes; re-platforming modifies the OS/platform; rebuilding is a full rewrite.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Rehost the application on Compute Engine using a custom image of the current OS
Why this is correct
Rehosting on Compute Engine with a custom image of the current OS is a classic 'lift-and-shift' strategy that preserves the exact kernel, libraries, and configuration of the legacy environment. Because no code changes or architectural changes are required, this approach minimizes migration risk and time-to-completion, allowing the team to move the application as-is. The custom image ensures parity with the on-premises OS, avoiding issues with unsupported or altered system dependencies.
- ✗
Rebuild the application from scratch on Cloud Run
Why it's wrong here
Rebuilding the application from scratch on Cloud Run is the most expensive and risky option because it involves rewriting the entire codebase, not just changing infrastructure. Cloud Run is a fully managed serverless container platform that requires the application to be containerized, adhere to stateless design principles, and scale independently, which a legacy monolithic application rarely satisfies. This approach effectively discards the existing investment and creates a new application, making it unsuitable for a quick migration.
- ✗
Re-platform the application to a supported OS version
Why it's wrong here
Re-platforming to a supported OS version entails swapping the underlying operating system, which can break the application due to differences in system libraries, binary compatibility, and configuration file paths. Even if the code is portable, the application may rely on OS-specific utilities or versions that are not present in the newer OS, forcing middleware or runtime upgrades that introduce regression risk. This approach is also not a minimal-change migration because it requires re-testing and often reconfiguring the entire environment.
- ✗
Refactor the application into microservices and deploy on GKE
Why it's wrong here
Refactoring the application into microservices and deploying on GKE requires decomposing the monolithic codebase into independently deployable services, which demands significant development resources and a fundamental architectural shift. The distributed nature introduces network latencies, data consistency challenges, and operational complexity around service discovery and inter-service communication. Since GKE is a Kubernetes platform, the team would also need to create Docker images and orchestrate containers, making this the most time-consuming and risky approach relative to the original goal.
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Cloud Digital Transformation
Key term
Compute Engine
Compute Engine is Google Cloud's Infrastructure-as-a-Service (IaaS) offering that lets you create and run virtual machines on Google's infrastructure.
Key term
Google Cloud
Google Cloud is a suite of cloud computing services offered by Google that provides infrastructure, platform, and software solutions over the internet.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This GCDL practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the GCDL exam.