The answer is `kubectl create secret generic my-reg --from-file=.dockerconfigjson=config.json`. This command is correct because it creates a generic secret and stores the contents of an existing Docker config file under the required key `.dockerconfigjson`, which Kubernetes automatically recognizes for image pull authentication. On the CKAD exam, this tests your ability to import pre-existing Docker credentials without using the `docker-registry` type, which is a common trap—many candidates mistakenly use `kubectl create secret docker-registry` when they already have a valid `config.json` file. The key insight is that `--from-file` maps the file’s content directly into the secret’s data field, and the `.dockerconfigjson` key name is mandatory for Kubernetes to interpret it correctly. Remember the mnemonic: “Generic with a dot-key” — you’re taking a local config file and packaging it as a generic secret under the `.dockerconfigjson` key, not creating a new registry secret from scratch.
CKAD Practice Question: Application Environment, Configuration and Security
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.
Which command creates a Docker registry secret from an existing Docker config file?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "which command"
Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
Option B is correct because `kubectl create secret generic` with `--from-file=.dockerconfigjson=config.json` creates a generic secret that stores the contents of an existing Docker config file (typically `~/.docker/config.json`) under the key `.dockerconfigjson`. This is the standard method for importing a pre-existing Docker configuration as a Kubernetes secret, which can then be used for image pull authentication.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 correct type is docker-registry with --from-file flag, but the key should be .dockerconfigjson.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CNCF often tests the distinction between `kubectl create secret docker-registry` (which creates a new secret from individual flags) and `kubectl create secret generic` with `--from-file` (which imports an existing config file), leading candidates to incorrectly choose option D because they assume `docker-registry` supports `--from-file`.
Detailed technical explanation
How to think about this question
Under the hood, Kubernetes expects the secret data for Docker registry authentication to be stored under the key `.dockerconfigjson` containing a valid Docker config JSON (as defined in the Docker CLI configuration format). When using `kubectl create secret generic --from-file=.dockerconfigjson=config.json`, the file content is directly injected into the secret without any transformation, preserving the exact structure needed by kubelet for pulling images. A common real-world scenario is when you have a pre-configured `config.json` from a CI/CD pipeline or a shared team environment, and you need to import it into multiple namespaces.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CKAD question in full detail.
Application Environment, Configuration and Security — This question tests Application Environment, Configuration and Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: kubectl create secret generic my-reg --from-file=.dockerconfigjson=config.json — Option B is correct because `kubectl create secret generic` with `--from-file=.dockerconfigjson=config.json` creates a generic secret that stores the contents of an existing Docker config file (typically `~/.docker/config.json`) under the key `.dockerconfigjson`. This is the standard method for importing a pre-existing Docker configuration as a Kubernetes secret, which can then be used for image pull authentication.
What should I do if I get this CKAD question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.