Focused, hands-on problems for sharpening your DevOps and server-side skills. Some teach specific concepts while others mirror real-world scenarios. Every challenge includes hints, feedback, and automated solution checks.
A Go service that has always been shipped as a static binary in a scratch-y image suddenly fails to start in a container, while the local build works as before. Find what recent changes caused it and fix the image without reverting them.
Set up your own OCI-compatible container registry with username/password authentication and HTTPS - the kind of protection you'd expect before using a registry in production.
Stand up a self-hosted container registry so you can push and pull images without relying on a third-party registry. Useful for tests, internal services, air-gapped environments, or just for poking at the OCI Distribution API.
An internal service is halfway through a Python-to-Go rewrite: the amd64 build already runs the new Go code while arm64 still ships the legacy Python one - same API, two completely different codebases and Dockerfiles. Can you build and push a single multi-platform image from the two independent single-platform variants?
Practice using docker login to authenticate against multiple private container registries with different credentials, then pull and push images across them.
Get container images onto a server that has no route to the Internet or access to a container registry.
Re-tag local container images with fully-qualified references and publish them to different registries using the 'docker tag' and 'docker push' commands.
Explore the OCI image index, manifests, and configuration of a remote multi-platform image - without pulling a single byte of filesystem layers into the local Docker daemon.
Pull a container image built for a non-native CPU architecture using the 'docker pull --platform' flag.
Investigate a potentially compromised CI host. A sandboxed "agent" running in the background is suspected of breaking out - confirm the breach and neutralize it without taking the sandbox down.
