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hardMultiple ChoiceObjective-mapped

CV0-004 Practice Question: Is troubleshooting a web application that is not…

Exhibit

Refer to the exhibit.

```
$ gcloud compute instances list
NAME        ZONE        MACHINE_TYPE  PREEMPTIBLE  STATUS
web-server  us-east1-b  e2-medium     true         RUNNING
db-server   us-east1-b  e2-standard-2               STOPPED

$ gcloud compute instances describe web-server --format='get(status,serviceAccounts.email)'
status: RUNNING
serviceAccounts.email: default@project.iam.gserviceaccount.com

$ gcloud compute instances get-serial-port-output web-server
...
[   10.123456] cloud-init: User data script started
[   10.654321] cloud-init: ERROR: Failed to fetch metadata from metadata server
...
```

A cloud engineer is troubleshooting a web application that is not responding. The engineer examines the serial console output of the web-server instance and finds the error shown in the exhibit. What is the MOST likely cause of this issue?

⚠ Common exam trap

The trap here is that candidates often associate connectivity issues with public IPs or firewall rules blocking external traffic, but the metadata server is an internal link-local address, so the firewall rule must be blocking internal traffic to 169.254.169.254 specifically.

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

✓

A firewall rule is blocking traffic to the metadata server IP address 169.254.169.254.

The error shown in the serial console output indicates that the instance cannot reach the metadata server at 169.254.169.254. This IP address is a link-local address used by cloud providers (e.g., AWS, GCP, Azure) to serve instance metadata, including user data scripts. If a firewall rule blocks traffic to this IP, the instance cannot retrieve its user data, causing the web application to fail to start or respond.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • ✗

    The service account associated with the instance is missing the required permissions.

    Why it's wrong here

    Missing permissions would cause API call failures, not metadata fetch errors.

  • ✗

    The instance is in a STOPPED state and cannot execute user data scripts.

    Why it's wrong here

    The serial output shows the instance is RUNNING.

  • ✗

    The instance does not have a public IP address assigned.

    Why it's wrong here

    Metadata server is accessible regardless of public IP; it's a link-local address.

  • ✓

    A firewall rule is blocking traffic to the metadata server IP address 169.254.169.254.

    Why this is correct

    The metadata server is accessed via link-local address; blocking this traffic prevents metadata retrieval.

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JA

Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

This CV0-004 practice question is part of Courseiva's free CompTIA 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 CV0-004 exam.