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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 DevOps and server-side problems with hints, feedback, and automated solution checks.
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A Simple Sandbox Breakout: Spot It and Stop It
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.
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Execute Host Commands Inside a Running Container
Leverage your knowledge of Linux namespaces to reach an application's internal debug interface without installing anything into the container.
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Run a Sidecar Container in the Namespace of Another Container
Learn how to run multiple Docker containers sharing the same PID, IPC, and network namespaces - a foundation of many advanced container use cases, including Kubernetes Pods construction and container debugging tools.
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Docker 101: Signal a Running Containerized Application
Practice using UNIX signals with containers for controlling application behavior: Send a SIGUSR1 to a containerized app to trigger its memory usage reporting.
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Free Up Disk Space by Removing Unused Docker Volumes
Your Docker host has been in use for a while. Anonymous and named volumes piled up, disk space is tight, and it's time to clean stuff up.
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Docker 101: Pass Environment Variables to Containers
Discover why host environment variables aren't visible to containers and how to properly pass them to containerized applications in Docker.
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Docker 101: Run a TTY-controlled Container and Explore the Effect of the -t Flag
Learn when to use the -t flag in 'docker run' to allocate a pseudo-TTY (terminal) for containers, enabling terminal-specific features like cursor control, colors, and signal handling.
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Install Docker Engine on Debian
Practice installing Docker on Debian and learn about the different components that make up Docker Engine.
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Install Docker Engine on Fedora
Practice installing Docker on Fedora and learn about the different components that make up Docker Engine.