What Docker Solves and How Containers Work

This lesson explains the practical problem Docker solves: making software run consistently across laptops, test environments, and production systems. Learners will connect common deployment failures to missing dependencies, configuration drift, operating system differences, and unclear runtime assumptions.

It also introduces how containers work at a conceptual level. Rather than treating Docker as magic, the lesson shows how images, containers, isolation, and shared host kernels fit together, while saving hands-on Dockerfile writing, networking, volumes, registries, and orchestration for later lessons.