Understanding containers from scratch: building one with Bash (no Docker, no magic)

Over the years, Docker has become a black box for many developers — we use it daily, but very few of us actually understand what happens under the hood.

I wanted to truly understand how containers isolate processes, manage filesystems, and set up networking. So I decided to build my own container from scratch using only Bash scripts — no Docker, no Podman, just Linux primitives like: • chroot for filesystem isolation • unshare and clone for process and namespace isolation • veth pairs for container networking • and a few iptables tricks for port forwarding

The result: a tiny container that runs a Node.js web app inside its own network and filesystem — built completely with shell commands.

Here’s the full deep dive https://youtu.be/FNfNxoOIZJs