- A
env: - name: CONFIG value: "$(CONFIGMAP)"
Why wrong: This is not a valid way to reference a ConfigMap.
- B
envFrom: - configMapRef: name: app-config
This mounts all keys from the ConfigMap as environment variables.
- C
volumes: - name: config configMap: name: app-config volumeMounts: - name: config mountPath: /etc/config
Why wrong: This mounts the ConfigMap as a volume, not as environment variables.
- D
env: - name: CONFIG valueFrom: configMapKeyRef: name: app-config key: config.yaml
Why wrong: This mounts a single key as an environment variable.
Question 208 of 997
How to Inject All ConfigMap Keys as Environment Variables in Kubernetes
This KCNA practice question tests your understanding of kubernetes fundamentals. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 developer wants to inject environment variables into a pod from a ConfigMap named 'app-config'. Which YAML snippet correctly mounts all key-value pairs from the ConfigMap as environment variables?
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
✓
envFrom: - configMapRef: name: app-config
Option B is correct because `envFrom` with a `configMapRef` injects all key-value pairs from the ConfigMap named 'app-config' as environment variables into the container. This is the standard Kubernetes method for bulk injection of ConfigMap data into environment variables, as opposed to selecting individual keys.
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.
- ✗
env: - name: CONFIG value: "$(CONFIGMAP)"
Why it's wrong here
This is not a valid way to reference a ConfigMap.
- ✓
envFrom: - configMapRef: name: app-config
Why this is correct
This mounts all keys from the ConfigMap as environment variables.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
volumes: - name: config configMap: name: app-config volumeMounts: - name: config mountPath: /etc/config
Why it's wrong here
This mounts the ConfigMap as a volume, not as environment variables.
- ✗
env: - name: CONFIG valueFrom: configMapKeyRef: name: app-config key: config.yaml
Why it's wrong here
This mounts a single key as an environment variable.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse `envFrom` (bulk injection) with `env` + `configMapKeyRef` (single key injection) or volume mounts (file-based injection), leading them to pick options that inject only one key or mount files instead of environment variables.
Detailed technical explanation
How to think about this question
Under the hood, `envFrom` with `configMapRef` iterates over all entries in the ConfigMap and creates an environment variable for each key, with the value set to the corresponding value. If a key is not a valid environment variable name (e.g., contains hyphens), Kubernetes will skip it silently, which can lead to missing variables in production — a subtle behavior to watch for. In real-world scenarios, this is commonly used for injecting configuration like database URLs or feature flags without hardcoding them in the pod spec.
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 KCNA 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
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
Kubernetes Fundamentals — study guide chapter
Learn the concepts, then practise the questions
- →
Kubernetes Fundamentals practice questions
Targeted practice on this topic area only
- →
All KCNA questions
997 questions across all exam domains
- →
Kubernetes and Cloud Native Associate KCNA study guide
Full concept coverage aligned to exam objectives
- →
KCNA practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related KCNA practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Kubernetes Fundamentals practice questions
Practise KCNA questions linked to Kubernetes Fundamentals.
Container Orchestration practice questions
Practise KCNA questions linked to Container Orchestration.
Cloud Native Architecture practice questions
Practise KCNA questions linked to Cloud Native Architecture.
Cloud Native Observability practice questions
Practise KCNA questions linked to Cloud Native Observability.
Cloud Native Application Delivery practice questions
Practise KCNA questions linked to Cloud Native Application Delivery.
KCNA fundamentals practice questions
Practise KCNA questions linked to KCNA fundamentals.
KCNA scenario practice questions
Practise KCNA questions linked to KCNA scenario.
KCNA troubleshooting practice questions
Practise KCNA questions linked to KCNA troubleshooting.
Practice this exam
Start a free KCNA practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this KCNA question test?
Kubernetes Fundamentals — This question tests Kubernetes Fundamentals — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: envFrom: - configMapRef: name: app-config — Option B is correct because `envFrom` with a `configMapRef` injects all key-value pairs from the ConfigMap named 'app-config' as environment variables into the container. This is the standard Kubernetes method for bulk injection of ConfigMap data into environment variables, as opposed to selecting individual keys.
What should I do if I get this KCNA question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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 →
Same concept, more angles
2 more ways this is tested on KCNA
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A DevOps engineer has created a ConfigMap named 'app-config' and wants to use it to set environment variables in a pod. Which field in the pod spec should reference the ConfigMap?
medium- A.spec.containers[].command
- B.spec.containers[].env.name
- C.spec.containers[].volumeMounts
- ✓ D.spec.containers[].envFrom
Why D: Option D is correct because `spec.containers[].envFrom` allows you to inject all key-value pairs from a ConfigMap (or Secret) as environment variables into a container in a single declaration. This field supports a `configMapRef` that references the ConfigMap by name, making it the appropriate spec field for bulk environment variable injection.
Variation 2. A DevOps engineer has created a ConfigMap named 'app-config' with some configuration data. They want to make that data available as environment variables in a pod. Which field in the pod spec should they use to achieve this?
medium- A.spec.volumes
- B.spec.containers[].volumeMounts
- ✓ C.spec.containers[].envFrom
- D.spec.containers[].env
Why C: Option C is correct because the `envFrom` field in the container spec allows you to inject all key-value pairs from a ConfigMap (or Secret) as environment variables into the container. This is the most direct and efficient way to expose ConfigMap data as environment variables without needing to specify each key individually.
Keep practising
More KCNA practice questions
- Which CNCF project provides a graduated service mesh implementation that includes features like traffic management, secu…
- A pod in the 'production' namespace is in a CrashLoopBackOff state. The pod has been running successfully for several da…
- You need to ensure that a pod runs on a node with SSD storage. How can you achieve this?
- Match each Kubernetes resource to its primary purpose.
- Match each Kubernetes security concept to its definition.
- Which three of the following are valid methods to create or update resources in Kubernetes? (Choose three.)
Last reviewed: Jun 24, 2026
This KCNA 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 KCNA 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.