Container debugging involves identifying and resolving issues in containerized applications running in Docker and Kubernetes environments, from startup failures to runtime crashes. While containers abstract away infrastructure complexity, they introduce unique debugging challenges: ephemeral filesystems, network isolation, and multi-layered configurations that require specialized tools and techniques. This cheat sheet covers the most common debugging commands first, followed by advanced forensic methods—ensuring you can diagnose anything from a simple port conflict to a segfault buried in a production pod.