99% of Developers Don't Get Docker

A deep dive into how Docker actually works under the hood, covering the evolution from hardware virtualization (VMs with hypervisors) to OS-level containerization. Explains the Linux kernel primitives that make containers possible: namespaces (PID, net, mnt, UTS) for isolation and cgroups for resource limits. Covers the union file system and copy-on-write strategy that makes images lightweight and fast. Also walks through Dockerfile optimization via layer caching, data persistence with volumes, and briefly compares Docker Swarm vs Kubernetes for orchestration and Docker vs Podman architecturally.