Dockerfile and Deployment Security Best Practices

An application image is built from an insecure Dockerfile.

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The task

Task

An application image is built from an insecure Dockerfile.

Requirements

Update the Dockerfile at /root/Dockerfile to run the container as the nobody user:

   USER nobody

Update the Deployment secure-app security context:

runAsUser: 65535
readOnlyRootFilesystem: true
privileged: false

Verify that the Deployment rolls out successfully.

Exam

CKS

Domain

Supply Chain Security

Grading

Programmatic · partial credit

Reference

Kubernetes docs ↗

What this tests

Scan images for vulnerabilities, harden Dockerfiles, generate SBOMs, and enforce image policy. On the CKS exam, Supply Chain Security tasks are graded purely on what you build in the cluster — not multiple choice — so the only way to get faster is to do them on a real cluster against a clock.

Practice it for real

prepium.sh drops you into your own isolated Kubernetes cluster in the browser — no install, no credit card. You solve the task in a real terminal, hit validate, and a programmatic checker scores exactly what you got right and wrong (with partial credit). The canonical solution unlocks after you attempt it, so you learn the fast, exam-ready way to do it.

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