Bocker: Docker implemented in around 100 lines of Bash (2015)

Original Article ↗ Hacker News Discussion ↗

Simplicity of Docker / Role of Bocker

  • Bocker shows that core Docker functionality is mostly “glue” around existing Linux features: namespaces, cgroups, union/overlay filesystems.
  • Many see this as both Docker’s strength (built on solid primitives) and a business risk (easy to re-implement).
  • Commenters emphasize Bocker as an educational tool to demystify containers, not a production replacement.

Where Docker Adds Value (and Where It Doesn’t)

  • Several argue Docker’s real value is in the image/OCI format and distribution workflow (caching, layering, “run anywhere”), not the runtime itself.
  • Some feel Docker should have doubled down on PaaS (like Cloud Run/Fly/Render) rather than Swarm, which is viewed as a failure vs Kubernetes.
  • Others note Docker became profitable focusing on Docker Desktop + Hub and standardization, not orchestration.

Alternatives on macOS/Windows/Linux

  • Strong criticism of Docker Desktop on macOS: seen as bloated, slow (VM + networked FS), and license-frustrating.
  • Popular alternatives mentioned: Rancher Desktop, OrbStack, Colima, Podman (with/without Podman Desktop), lazydocker as a TUI.
  • Some report smooth migrations to Rancher Desktop/OrbStack; others describe painful failed migrations away from Docker Desktop due to subtle filesystem/network integration issues and script compatibility.
  • OrbStack is praised for efficiency and UX but has reported IPv6-related DNS issues for Kubernetes pods.

FOSS, Podman, and “Container ≠ Docker”

  • Multiple comments highlight Podman, runc, systemd-nspawn, LXC, and rootless approaches as open alternatives.
  • Debate over how “open” Docker is: core CLI/daemon/buildkit/compose are open source; Docker Desktop GUI and its license are proprietary.
  • Some think Docker is “lucky” that people equate containers with Docker; Podman is seen as a superior drop-in in some contexts.

Technical Details & Gotchas

  • Rootless containers on Linux are described as hard, especially networking; tools like rootlesskit and slirp4netns trade performance and security.
  • Docker on macOS/Windows always implies a Linux VM, with performance implications and limited GPU/MPS support.
  • Overlayfs (or ZFS/Btrfs snapshots) is cited as a powerful technique for speeding up large CI checkouts.
  • Warnings about manually compiling util-linux (risk of breaking mount), and about old distro Docker packages lagging features (buildx, modern compose).

Meta / Learning / Misc

  • Many enjoy small Bash tools (like Bocker, minimal load balancers, chroot/proot wrappers) as a way to truly understand infrastructure.
  • There is acceptance that many GitHub projects have unfinished TODOs; sometimes software is simply “done.”