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Reach a Distroless Container's Debug Endpoint From a Sidecar Container
A distroless container serves a debug interface on its own loopback address. Can you reach this debug endpoint using nothing but standard Docker commands?
Challenges
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.
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Run the Application's Test Suite in a Container Without Network Access
You are containerizing the dev workflows of a legacy Python service and you need to find out which external services its test suite talks to. Can you think of an easy way to do it?
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Turn Off a Feature Flag in a Production Redis Server Using a Local Containerized redis-cli
Ad-hoc containers are a handy way to run command-line tools without installing them on the host. Use one to access a production Redis server and turn off a feature flag. But beware of the gotcha: the production server can only be tunneled to the localhost.
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Docker 101: Publish All Exposed Ports on Random Host Ports to Avoid Port Conflicts
Can you get several builds of an app running side by side without port conflicts, so you can test them simultaneously?
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Connect Two Network Namespaces
Prove your Linux networking skills by connecting two network namespaces with a virtual Ethernet device.
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Set Up Network Address Translation (NAT) for a Container
There is a container that can reach the host only through its veth pair and cannot call any other addresses. Can you connect it to the outside world?