Build your first container image

CKAD v1.35 · Application Design and Build (20%) → "Define, build and modify container images" Target time: 20 minutes

The browser lab provides Docker, kind, kubectl, jq, and registry access. Use the disposable muscle cluster only. Run commands from k8s-muscle/.

Setup copies a tiny Go HTTP server into this scenario's workspace/ directory. Do not modify starter/ or the copied main.go.

1. Write workspace/Dockerfile using a build stage named build and a separate Alpine runtime stage (keep its sh and id tools for inspection). Compile a static Linux binary at /app/server in the final image. The final image must contain neither Go nor /src/main.go.
2. The image must default to numeric UID 10001, expose 8080, and start the server without a shell wrapper. Tag it k8sm-image-lab:v1.
3. Load it into kind's muscle cluster. Do not push to a registry.
4. In namespace image-build, create Deployment hello, two replicas, using that image with imagePullPolicy: Never. Both replicas must become ready.
5. Expose it as Service hello, port 80 to container port 8080. Requests from inside the cluster must return image-build-ok.
6. Modify the Deployment, not the source code, to set MESSAGE=release-two. After rollout, the same Service must return release-two.

The grader checks the final release-two state, image user, absence of build artifacts, and live traffic. It cannot prove your exact command history. Reset deletes this namespace and workspace and removes this lab's local image tag; the next attempt must rebuild and reload the image.