This CKAD practice question tests your understanding of application environment, configuration and security. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A pod uses a service account 'my-sa' with a RoleBinding that grants get and list on pods in namespace 'app'. The pod runs a process that calls the Kubernetes API to list pods. However, the API call returns 403. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
The API server is not running.
Why wrong: If API server were down, the error would be connection error, not 403.
The RoleBinding is in the wrong namespace.
Why wrong: RoleBinding is in 'app' namespace, correct.
The pod does not have the service account token mounted.
If automountServiceAccountToken is false, no token is available.
The Role does not include list permission.
Why wrong: Role includes list, so that is not the issue.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The pod does not have the service account token mounted.
Option C is correct because the pod must have the service account token mounted to authenticate to the Kubernetes API server. By default, Kubernetes automatically mounts the service account token into pods via a projected volume at /var/run/secrets/kubernetes.io/serviceaccount/token. If the pod is configured with automountServiceAccountToken: false or the token is not mounted, the API client cannot authenticate, resulting in a 403 Forbidden error even if the RoleBinding grants the correct permissions.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
The API server is not running.
Why it's wrong here
If API server were down, the error would be connection error, not 403.
The RoleBinding is in the wrong namespace.
Why it's wrong here
RoleBinding is in 'app' namespace, correct.
The pod does not have the service account token mounted.
Why this is correct
If automountServiceAccountToken is false, no token is available.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
The Role does not include list permission.
Why it's wrong here
Role includes list, so that is not the issue.
Common exam traps
CNCF often tests the distinction between authentication (who you are) and authorization (what you can do); the trap here is that candidates assume a 403 always means a missing RBAC permission, when in fact it can also result from a missing or invalid service account token causing authentication failure.
Detailed technical explanation
Kubernetes service account tokens are JWTs (JSON Web Tokens) that are automatically mounted into pods via a projected volume. The token is used by the client (e.g., kubectl, client-go) to authenticate to the API server's authentication webhook or token review endpoint. If the token is not mounted, the client sends an unauthenticated request, which the API server rejects with a 403 Forbidden (not 401 Unauthorized) because the request is processed as anonymous with no RBAC permissions. In real-world scenarios, this often occurs when a pod is created with automountServiceAccountToken: false or when using custom pod security policies that disable token mounting.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the CKAD exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
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FAQ
Application Environment, Configuration and Security — This question tests Application Environment, Configuration and Security — Read the scenario before looking for a memorised answer..
The correct answer is: The pod does not have the service account token mounted. — Option C is correct because the pod must have the service account token mounted to authenticate to the Kubernetes API server. By default, Kubernetes automatically mounts the service account token into pods via a projected volume at /var/run/secrets/kubernetes.io/serviceaccount/token. If the pod is configured with automountServiceAccountToken: false or the token is not mounted, the API client cannot authenticate, resulting in a 403 Forbidden error even if the RoleBinding grants the correct permissions.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
This CKAD practice question is part of Courseiva's free CNCF 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 CKAD exam.
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