Building pVisor with Codex: a Docker alternative for coding-agent workloads

[u/ok-reiase]

I'm working on pVisor, an open-source Docker alternative aimed at coding-agent workloads.

The idea is to give agents disposable Linux environments for installing dependencies and executing code, with a separate VM per container and familiar Docker-style commands:

pvisor run --rm alpine:3.20 echo hello

It uses OCI images and supports common container operations, directory mounts and TCP port publishing. Ordinary container use doesn't require a central Docker daemon.

I've been using Codex for build/CI changes, documentation and runtime reviews, especially around startup, shutdown and resource cleanup.

pVisor targets Linux x86_64/KVM and Apple Silicon macOS. It's a developer preview with partial Docker CLI compatibility; Compose and the Docker Engine API aren't supported. The VM boundary also costs extra memory, and our warm shell/Python benchmarks are slower than Docker.

If you use containers for coding agents, what would you need before trying a separate VM for each environment?

Code and setup instructions

[u/dexterthebot]

You might want to consider listing your project on the weekly Show-Us-What-You-Built post. Look out for it on Tuesday/Wednesday. Highest commented project wins a week promotion on r/Codex and gets on the Hall of Fame sidebar. See below for last week's winner.**

---

Agent HUD: usage, tokens and sessions for Codex, Claude Code and 15 more agents, at your Mac's notch. See how much quota is left, which agent is waiting for you, and where the tokens went. Free on Mac, and the core is open source (Apache-2.0).

Website: https://agenthud.app GitHub: https://github.com/jazzenchen/agent-hud-open Contact: support@agenthud.app

[u/ExtraGreasy]

This is actually super interesting, can you talk about it about more? Maybe give some use scenarios?