Clone, a small Rust VMM, forks VMs in under 20ms via CoW
We needed a secure, multi-tenant way to offer shell accounts to users, but most VMMs were using too much memory and containers are unsafe. With clone, VMs are now more memory efficient than containers in most cases. Since many other projects on HN looked like they were doing this too, open sourcing this was the right thing to do. Feel free to use in whole or in part as you see fit!
Clone, a small Rust VMM, forks VMs in under 20ms via CoW launched on April 19, 2026 with 11 votes, #1,205 of 21,248 launches that month and more than 90% of that year's launches.
In plain words
Clone is a lightweight virtual machine monitor written in Rust that creates new VMs in under 20 milliseconds using copy-on-write technology. It addresses the need for secure, multi-tenant shell account hosting by offering memory efficiency that typically exceeds container solutions while maintaining VM-level security isolation. The tool is designed for developers and service providers who require fast VM instantiation without the memory overhead of traditional hypervisors.
written from the facts on this page · September 2026
From the sources
Minimal VMM for multi-tenant dev shells and serverless - unixshells/clone
Does a similar job
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I think that asdf (https://asdf-vm.com) was a great idea for a project. It helps consolidate installing and running different programming languages into a similar UX. It also is built with a plugin interface that makes it easy to build support for new languages. However it is so slow. I was just testing `node -v` and it was taking ~900ms. That kind of overhead is completely unusable. My shell prompt uses runtimes inside of it for various things so this effectively makes every command take multiple seconds to complete. So I rebuilt it in Rust but using the same plugin ecosystem so…
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High-order Virtual Machine (HVM) – A Parallel Functional Runtime2022 · github.com · ▲150HVM1 (2022): a massively parallel, optimal functional runtime in Rust - HigherOrderCO/HVM1
Second State VM2020 · secondstate.io · ▲78High performance secure & portable Rust functions in Node.js
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Source: Show HN post ↗
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