This CKAD practice question tests your understanding of application environment, configuration and security. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 user wants to create a Kubernetes Secret for storing Docker registry credentials (username and password). Which type of Secret should they use?
kubernetes.io/tls
Why wrong: This type is for TLS certificates and keys.
Opaque
Why wrong: Opaque can store arbitrary data but is not the standard type for Docker credentials.
kubernetes.io/dockerconfigjson
This type stores a .dockerconfigjson file for Docker registry authentication.
kubernetes.io/basic-auth
Why wrong: Basic-auth is for username/password for basic authentication, but not specifically for Docker registries.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
kubernetes.io/dockerconfigjson
Option C is correct because `kubernetes.io/dockerconfigjson` is the dedicated Secret type for storing Docker registry credentials in the format expected by `docker login`. It automatically encodes the username and password into a `.dockerconfigjson` field, which is used by Kubernetes to pull images from private registries. This type is required when referencing a `imagePullSecret` in a Pod spec.
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.
kubernetes.io/tls
Why it's wrong here
This type is for TLS certificates and keys.
Opaque
Why it's wrong here
Opaque can store arbitrary data but is not the standard type for Docker credentials.
kubernetes.io/dockerconfigjson
Why this is correct
This type stores a .dockerconfigjson file for Docker registry authentication.
Related concept
Read the scenario before looking for a memorised answer.
kubernetes.io/basic-auth
Why it's wrong here
Basic-auth is for username/password for basic authentication, but not specifically for Docker registries.
Common exam traps
The trap here is that candidates often choose `Opaque` (Option B) because they think any secret can be used for Docker credentials, but the CKAD exam expects you to know that only `kubernetes.io/dockerconfigjson` provides the correct format and automatic integration with image pull secrets.
Detailed technical explanation
Under the hood, `kubernetes.io/dockerconfigjson` stores the credentials as a JSON object in the `.dockerconfigjson` field, following the Docker `config.json` format (e.g., `{"auths":{"registry.example.com":{"auth":"base64(username:password)"}}}`). When used as an `imagePullSecret`, the kubelet reads this field and passes the credentials to the container runtime (e.g., containerd or CRI-O) during image pull. A subtle behavior is that the secret must be in the same namespace as the Pod, and the registry URL must exactly match the one used in the image reference.
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: kubernetes.io/dockerconfigjson — Option C is correct because `kubernetes.io/dockerconfigjson` is the dedicated Secret type for storing Docker registry credentials in the format expected by `docker login`. It automatically encodes the username and password into a `.dockerconfigjson` field, which is used by Kubernetes to pull images from private registries. This type is required when referencing a `imagePullSecret` in a Pod spec.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 25, 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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