Cloud Run vs Cloud Functions decision in GCP - Practice Questions

Challenge - 5 Problems

🧠 Conceptual

intermediate

Choosing between Cloud Run and Cloud Functions for HTTP workloads

You have a simple HTTP API that needs to scale automatically and handle short requests. Which service is best suited for this?

A Cloud Run, because it supports containerized apps and scales automatically for HTTP requests.

B Cloud Functions, because it only supports background tasks, not HTTP requests.

C Cloud Run, because it requires manual scaling and is better for batch jobs.

D Cloud Functions, because it cannot scale automatically.

💡 Hint

Think about which service supports containers and automatic scaling for HTTP.

Cloud Run supports containerized applications and automatically scales based on HTTP traffic. Cloud Functions also supports HTTP but is more limited to function code rather than full containers.

❓ Architecture

intermediate

Selecting a service for event-driven processing with short execution time

You want to process events from a Pub/Sub topic with a function that runs quickly and scales automatically. Which service should you choose?

A Cloud Functions, because it natively integrates with Pub/Sub and scales automatically for short tasks.

B Cloud Run, because it is designed for event-driven functions only.

C Cloud Run, because it cannot be triggered by Pub/Sub events.

D Cloud Functions, because it requires manual scaling for event triggers.

💡 Hint

Consider which service integrates directly with Pub/Sub and is optimized for short event processing.

Cloud Functions natively supports Pub/Sub triggers and automatically scales for short-lived event processing. Cloud Run can be triggered by Pub/Sub but requires additional setup.

❓ security

advanced

Securing a Cloud Run service with authentication

You deploy a Cloud Run service that should only be accessible by authenticated users from your organization. Which approach enforces this?

A Set the Cloud Run service to allow unauthenticated invocations and rely on app code for authentication.

B Make the Cloud Run service public and use firewall rules to block external IPs.

C Use Cloud Functions instead, because Cloud Run cannot restrict access.

D Configure Cloud Run to require authentication and use Identity-Aware Proxy (IAP) to restrict access to your organization.

💡 Hint

Think about built-in Google Cloud tools for authentication and access control.

Cloud Run can require authentication and integrates with IAP to restrict access to users in your organization. Allowing unauthenticated access or relying on firewall rules is less secure.

✅ Best Practice

advanced

Optimizing cost for a service with unpredictable traffic

You have a backend service with unpredictable traffic spikes. You want to minimize cost while ensuring fast response times. Which service and configuration is best?

A Use Cloud Functions with manual scaling to control costs.

B Use Cloud Run with minimum instances set to zero to scale down to zero when idle and scale up quickly on demand.

C Use Cloud Run with minimum instances set to a high number to avoid cold starts.

D Use Cloud Functions with a fixed number of instances to handle spikes.

💡 Hint

Consider how to balance cost and performance with scaling settings.

Cloud Run can scale down to zero instances to save cost and scale up quickly on demand. Setting minimum instances high increases cost. Cloud Functions scales automatically but you cannot fix instance count.

❓ service_behavior

expert

Understanding request timeout behavior differences

You deploy a Cloud Function and a Cloud Run service. Both receive HTTP requests that take 10 minutes to process. What happens to the requests?

A Cloud Run will timeout before 10 minutes; Cloud Functions can handle requests longer than 10 minutes.

B Both Cloud Functions and Cloud Run allow unlimited request duration by default.

C Cloud Functions will timeout before 10 minutes; Cloud Run can be configured to allow 10-minute or longer requests.

D Both services timeout at exactly 5 minutes and drop the requests.

💡 Hint

Check default and maximum request timeout limits for each service.

Cloud Functions has a maximum timeout of 9 minutes. Cloud Run allows configuring request timeout up to 60 minutes or more, so it can handle longer requests.

Practice

1. Which Google Cloud service is best suited for running simple event-driven code without managing servers?

easy

A. Compute Engine

B. Cloud Run

C. Cloud Functions

D. App Engine

Solution

1. Step 1: Understand event-driven code needs

   Simple event-driven code triggers automatically on events and requires minimal setup.

2. Step 2: Match service to event-driven model

   Cloud Functions is designed for event-driven code without server management.

3. Final Answer:

   Cloud Functions -> Option C

4. Quick Check:

   Event-driven code = Cloud Functions [OK]

Hint: Simple event-driven? Choose Cloud Functions [OK]

Common Mistakes:

• Choosing Cloud Run for simple event-driven tasks
• Confusing Compute Engine with serverless options
• Thinking App Engine is event-driven by default

2. Which of the following is the correct way to deploy a container image to Cloud Run using gcloud CLI?

easy

A. gcloud run deploy SERVICE --image IMAGE_URL --platform managed

B. gcloud functions deploy SERVICE --image IMAGE_URL

C. gcloud compute instances create SERVICE --image IMAGE_URL

D. gcloud app deploy SERVICE --image IMAGE_URL

Solution

1. Step 1: Identify correct command for Cloud Run deployment

   Cloud Run uses 'gcloud run deploy' with --image and --platform flags.

2. Step 2: Eliminate incorrect commands

   Functions, Compute, and App Engine use different commands and flags.

3. Final Answer:

   gcloud run deploy SERVICE --image IMAGE_URL --platform managed -> Option A

4. Quick Check:

   Cloud Run deploy = gcloud run deploy [OK]

Hint: Cloud Run deploy uses 'gcloud run deploy' with --image [OK]

Common Mistakes:

• Using 'gcloud functions deploy' for Cloud Run
• Confusing Compute Engine commands with Cloud Run
• Omitting --platform flag for Cloud Run

3. Given this scenario: You have a containerized app that needs to handle HTTP requests with custom runtime and environment variables. Which service will work correctly?

1. Deploy container to Cloud Run
2. Set environment variables in deployment
3. App handles HTTP requests

medium

A. Cloud Functions only

B. Cloud Run only

C. Both Cloud Run and Cloud Functions

D. Neither Cloud Run nor Cloud Functions

Solution

1. Step 1: Check container support and environment variables

   Cloud Run supports containerized apps and environment variables; Cloud Functions has limited container support and environment variable use.

2. Step 2: Match HTTP handling with service capabilities

   Cloud Run is designed for HTTP container apps with custom runtimes; Cloud Functions is for simpler functions.

3. Final Answer:

   Cloud Run only -> Option B

4. Quick Check:

   Container + env vars + HTTP = Cloud Run [OK]

Hint: Containerized HTTP app? Use Cloud Run [OK]

Common Mistakes:

• Assuming Cloud Functions supports full container apps
• Ignoring environment variable support differences
• Thinking both services handle custom runtimes equally

4. You tried deploying a container to Cloud Functions but got an error. What is the likely cause?

medium

A. Cloud Functions requires source code, not containers

B. Cloud Functions requires container images from Container Registry

C. Cloud Functions supports containers but only with specific runtimes

D. Cloud Functions supports containers only in beta

Solution

1. Step 1: Understand Cloud Functions deployment model

   Cloud Functions deploys source code or zipped code, not container images directly.

2. Step 2: Identify cause of deployment error

   Trying to deploy a container image causes error because Cloud Functions expects source code.

3. Final Answer:

   Cloud Functions requires source code, not containers -> Option A

4. Quick Check:

   Cloud Functions deploys source code only [OK]

Hint: Cloud Functions deploys code, not containers [OK]

Common Mistakes:

• Thinking Cloud Functions supports container images
• Confusing beta features with general availability
• Assuming all serverless services accept containers

5. Your team needs to deploy a microservice that requires custom libraries, runs on HTTP, and must scale automatically. You want to avoid managing servers but need full control over the runtime environment. Which service should you choose and why?

hard

A. Compute Engine, because it offers full control and automatic scaling

B. Cloud Functions, because it scales automatically and supports custom runtimes

C. App Engine Standard, because it supports custom libraries and auto-scaling

D. Cloud Run, because it runs containerized apps with full runtime control and auto-scaling

Solution

1. Step 1: Analyze requirements for runtime control and scaling

   Need full runtime control and automatic scaling without managing servers.

2. Step 2: Match service capabilities

   Cloud Run runs containerized apps with full control and auto-scales; Cloud Functions has limited runtime control; App Engine Standard has restrictions; Compute Engine requires server management.

3. Final Answer:

   Cloud Run, because it runs containerized apps with full runtime control and auto-scaling -> Option D

4. Quick Check:

   Custom runtime + auto-scale + no servers = Cloud Run [OK]

Hint: Full control + auto-scale? Pick Cloud Run [OK]

Common Mistakes:

• Choosing Cloud Functions for full runtime control
• Confusing App Engine Standard with container support
• Selecting Compute Engine despite server management needs