- A
Change tag to 'app:stable'
Why wrong: Stable tags can still be updated and are not immutable.
- B
Set 'replicas: 1'
Why wrong: Replica count does not affect image immutability.
- C
Use 'image: app@sha256:abc123...'
Using a digest ensures the exact image layer is used, providing immutability.
- D
Add 'imagePullPolicy: Always'
Why wrong: This forces a pull but still uses a mutable tag; the image could change.
Question 950 of 997
How to Use Image Digests for Immutable and Traceable Deployments
This CKS practice question tests your understanding of supply chain security. 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 security audit reveals that a Deployment uses an image with a mutable tag 'app:latest'. Which change ensures the image is immutable and traceable?
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
✓
Use 'image: app@sha256:abc123...'
Option C is correct because using the image digest (e.g., `image: app@sha256:abc123...`) pins the container image to an immutable, content-addressable identifier. Unlike mutable tags, the digest is a cryptographic hash of the image manifest, ensuring that every pull returns the exact same image, which is critical for traceability and supply chain security.
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.
- ✗
Change tag to 'app:stable'
Why it's wrong here
Stable tags can still be updated and are not immutable.
- ✗
Set 'replicas: 1'
Why it's wrong here
Replica count does not affect image immutability.
- ✓
Use 'image: app@sha256:abc123...'
Why this is correct
Using a digest ensures the exact image layer is used, providing immutability.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Add 'imagePullPolicy: Always'
Why it's wrong here
This forces a pull but still uses a mutable tag; the image could change.
Common exam traps
Common exam trap: answer the scenario, not the keyword
A common misconception is that using a 'stable' tag provides immutability, but in Kubernetes, any tag can be reassigned. Only the image digest (SHA256) guarantees a specific image version, ensuring traceability and supply chain security.
Detailed technical explanation
How to think about this question
Image digests are computed from the manifest’s content using SHA-256 (or SHA-512) as defined in the OCI Distribution Spec. When using a digest, the container runtime (e.g., containerd) verifies the manifest hash before pulling layers, preventing tampering or accidental drift. In a real-world CI/CD pipeline, you can capture the digest from the registry after a build and inject it into the Deployment manifest via tools like `kustomize` or `kyverno` to enforce immutability.
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 CKS 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.
- →
Supply Chain Security — study guide chapter
Learn the concepts, then practise the questions
- →
Supply Chain Security practice questions
Targeted practice on this topic area only
- →
All CKS questions
997 questions across all exam domains
- →
Certified Kubernetes Security Specialist CKS study guide
Full concept coverage aligned to exam objectives
- →
CKS practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related CKS practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Monitoring Logging and Runtime Security practice questions
Practise CKS questions linked to Monitoring Logging and Runtime Security.
Cluster Setup and Hardening practice questions
Practise CKS questions linked to Cluster Setup and Hardening.
System Hardening practice questions
Practise CKS questions linked to System Hardening.
Minimize Microservice Vulnerabilities practice questions
Practise CKS questions linked to Minimize Microservice Vulnerabilities.
Supply Chain Security practice questions
Practise CKS questions linked to Supply Chain Security.
Monitoring, Logging and Runtime Security practice questions
Practise CKS questions linked to Monitoring, Logging and Runtime Security.
Cluster Setup practice questions
Practise CKS questions linked to Cluster Setup.
Cluster Hardening practice questions
Practise CKS questions linked to Cluster Hardening.
CKS fundamentals practice questions
Practise CKS questions linked to CKS fundamentals.
CKS scenario practice questions
Practise CKS questions linked to CKS scenario.
CKS troubleshooting practice questions
Practise CKS questions linked to CKS troubleshooting.
Practice this exam
Start a free CKS 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 CKS question test?
Supply Chain Security — This question tests Supply Chain Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use 'image: app@sha256:abc123...' — Option C is correct because using the image digest (e.g., `image: app@sha256:abc123...`) pins the container image to an immutable, content-addressable identifier. Unlike mutable tags, the digest is a cryptographic hash of the image manifest, ensuring that every pull returns the exact same image, which is critical for traceability and supply chain security.
What should I do if I get this CKS 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
1 more ways this is tested on CKS
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 security policy requires that all container images use SHA-based digests instead of tags. Which approach ensures this in a Deployment YAML?
medium- A.Use the 'image' field with a tag and also set 'digest' field
- B.Set imagePullPolicy: Always and use tags
- ✓ C.Use the image field with a digest, e.g., 'image: nginx@sha256:abc123'
- D.Set imagePullPolicy: IfNotPresent and use tags
Why C: Option C is correct because Kubernetes supports using a SHA-based digest in the `image` field, which ensures the exact image content is pulled regardless of tag changes. By specifying the image as `nginx@sha256:abc123`, the container runtime fetches the image by its immutable digest, guaranteeing supply chain integrity and compliance with the security policy.
Keep practising
More CKS practice questions
- Which flag is used to restrict the kubelet's ability to modify node status and pods?
- A Falco rule has priority `WARNING` and output: `Sensitive file opened (user=%user.name command=%proc.cmdline file=%fd.n…
- Falco detects a shell being opened inside a container. Which Falco rule field is used to specify the syscall condition f…
- A security audit reveals that a ServiceAccount named 'monitor' has a ClusterRoleBinding to the cluster-admin role. What…
- Match each Kubernetes security component to its description.
- Match each Kubernetes certificate type to its usage.
Last reviewed: Jul 4, 2026
This CKS 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 CKS 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.