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Products that do what Sub-millisecond VM sandboxes using CoW memory forking does

I wanted to see how fast an isolated code sandbox could start if I never had to boot a fresh VM. So instead of launching a new microVM per execution, I boot Firecracker once with Python and numpy already loaded, then snapshot the full VM state. Every execution after that creates a new KVM VM backed by a `MAP_PRIVATE` mapping of the snapshot memory, so Linux gives me copy-on-write pages automatically. That means each sandbox starts from an already-running Python process inside a real VM, runs the code, and exits. These are real KVM VMs, not containers: separate guest kernel, separate guest…

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  2. 2TV
  3. 3CA

    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!

    Apr 2026 · github.com

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    Spin up secure sandboxes in ~100 ms

    Nov 2025

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    I'm excited to introduce Zerobox, a cross-platform, single binary process sandboxing CLI written in Rust. It uses the sandboxing crates from the OpenAI Codex repo and adds additional functionalities like secret injection, SDK, etc. Watch the demo: https://www.youtube.com/watch?v=wZiPm9BOPCg Zerobox follows the same sandboxing policy as Deno which is deny by default. The only operation that the command can run is reading files, all writes and network I/O are blocked by default. No VMs, no Docker, no remote servers. Want to block reads to /etc? zerobox…

    Mar 2026 · github.com

  6. 6FN

    forkrun is the culmination of a 10-year-long journey focused on "how to make shell parallelization fast". What started as a standard "fork jobs in a loop" has turned into a lock-free, CAS-retry-loop-free, SIMD-accelerated, self-tuning, NUMA aware shell-based stream parallelization engine that is (mostly) a drop-in replacement for xargs -P and GNU parallel. On my 14-core/28-thread i9-7940x, forkrun achieves: * 200,000+ batch dispatches/sec (vs ~500 for GNU Parallel) * ~95–99% CPU utilization across all 28 logical cores, even when the workload is non-existant (bash no-ops / `:`)…

    Mar 2026 · github.com

  7. 7LA

    I built LocalGPT over 4 nights as a Rust reimagining of the OpenClaw assistant pattern (markdown-based persistent memory, autonomous heartbeat tasks, skills system). It compiles to a single ~27MB binary — no Node.js, Docker, or Python required. Key features: - Persistent memory via markdown files (MEMORY, HEARTBEAT, SOUL markdown files) — compatible with OpenClaw's format - Full-text search (SQLite FTS5) + semantic search (local embeddings, no API key needed) - Autonomous heartbeat runner that checks tasks on a configurable interval - CLI + web interface + desktop GUI - Multi-provider:…

    Feb 2026 · github.com

  8. 8WA

    Hey HN, this is Will and David from Fortress (https://news.ycombinator.com/item?id=41426998). We use a lot of async Rust internally, and created this library out of a need for an async-aware concurrent hashmap since there weren’t many available in the Rust ecosystem. Whirlwind is a sharded HashMap with a fully asynchronous API. Just as dashmap is a replacement for std::sync::RwLock, whirlwind aims to be a replacement for tokio::sync::RwLock. It has a similar design and performance characteristics to dashmap, but seems to perform better in read-heavy workloads with tokio's…

    2024 · github.com

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  10. 10LO

    We just open-sourced Lume - a tool we built after hitting walls with existing virtualization options on Apple Silicon. No GUI, no complex stacks - just a single binary that lets you spin up macOS or Linux VMs via CLI or API. Why we built Lume: - Run native macOS VMs in 1 command, using Apple Virtualization.Framework: `lume run macos-sequoia-vanilla:latest` - Prebuilt images on https://ghcr.io/trycua (macOS, Ubuntu on ARM) - API server to manage VMs programmatically `POST /lume/vms` - A python SDK on github.com/trycua/pylume Run prebuilt macOS images in just…

    2025 · github.com

  11. 11KD

    I've built this to make it easy to host your own infra for lightweight VMs at large scale. Intended for exec of AI-generated code, for CICD runners, or for off-chain AI DApps. Mainly to avoid Docker-in-Docker dangers and mess. Super easy to use with CLI / Python SDK, friendly to AI engs who usually don't like to mess with VM orchestration and networking too much. Defense-in-depth philosophy. Would love to get feedback (and contributors: clear & exciting roadmap!), thx

    Oct 2025 · github.com

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    A fast, rootless sandbox and virtual resource runtime for any workload, including untrusted and AI-generated code. Daemonless: a real, kernel-enforced container in ~3.5 ms from an OCI image, out of one static binary - getkern/kern

    13d ago · github.com

  14. 14AD

    To try it out, simply build the project yourself from source, or use attached bootable ISO image of the system (in Releases on Github) and run it in QEMU. https://blog.vxn.dev/rou2exos-rusted-edition

    2025 · github.com

  15. 15MP

    Hi HN! Excited to launch machine0, a CLI that makes it easy to create, provision and snapshot persistent NixOS (& Ubuntu) VMs. You can think of machine0 as a modern VPS provider. VMs stay on unless switched-off (with 99.99% uptime), they have static IPs and HTTPS endpoints, 1-60 vCPU, up to 240GB RAM and optionally GPUs. The CLI provides commands to manage lifecycle, snapshots and also provision the VMs using Nix flakes or Ansible playbooks. VMs are priced by the minute of usage. What makes machine0 unique is that it has first class support for NixOS! In a nutshell, NixOS lets you define…

    Jun 2026 · machine0.io

  16. 16EV

    2024 · github.com

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  18. 18WB

    Over the past few months, as we scaled our internal AI Agents, we hit a dead end: Running LLM-generated arbitrary code in Docker is basically running naked on security due to container escape risks. But using full traditional VMs takes minutes to boot and eats too much memory to support high-density concurrency. We loved the developer experience of SaaS sandboxes on the market, but they are closed-source, expensive, and have too high a barrier to entry for self-hosting. So, our team decided to build our own. After months of grinding, using RustVMM and KVM, we built a blazing-fast,…

    Apr 2026 · github.com

  19. 19II

    Hi HN, To truly understand how operating systems and network protocols work, I decided to combine two classic learning tools: the xv6 teaching OS and a from-scratch TCP/IP stack. I'm excited to share the result: my own from-scratch TCP/IP networking stack running directly inside the xv6-riscv (https://github.com/pandax381/xv6-riscv-net) kernel. The project uses a modern virtio-net driver, allowing it to run seamlessly in QEMU and communicate with the host machine. Key features: - From-Scratch Stack: The core is powered by microps…

    2025 · github.com

  20. 20MM

    This project contains no code from Linux, BSD, Minix, or any other OS. Everything up until this point is written entirely from scratch, including a pure microkernel (that only implements multiprocessor priority scheduling, memory management, and interprocess communication), a work-in-progress implementation of the standard C library, and a variety of servers that provide drivers and other essential OS functionality. At the time of writing this post, the servers provide drivers for the keyboard, NVMe SSDs (that works on real hardware), a Unix-like virtual file system (with a single root…

    2024 · github.com

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    High performance secure & portable Rust functions in Node.js

    2020

  22. 22AC

    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…

    2023

  23. 23BS

    Bhatti spins up Linux VMs on any box with KVM — Pi 5, Hetzner AX, cloud VM with nested virt. - Each VM has its own kernel, filesystem, and IP - Idle VMs pause their CPUs and snapshot themselves to disk; the next request wakes them in 3.7ms warm or 360ms cold (p50, Hetzner AX102) - Publish any port → public URL with auto-wake on first hit - Pull any OCI/Docker image as a rootfs, or save a running sandbox as one - Multi-tenant from day one — per-user bridges, encrypted secrets, rate limits - Single Go binary, Apache 2.0 The decisions page is the most fun read on the site: vsock state…

    May 2026 · bhatti.sh

  24. 24SU

    Hi everyone, I built a runtime to isolate untrusted code using wasm sandboxes. Basically, it protects your host system from problems that untrusted code can cause. We’ve had a great discussion about sandboxing in Python lately that elaborates a bit more on the problem [1]. In TypeScript, wasm integration is even more natural thanks to the close proximity between both ecosystems. The core is built in Rust. On top of that, I use WASI 0.2 via wasmtime and the component model, along with custom SDKs that keep things as idiomatic as possible. For example, in Python we have a simple decorator:…

    Feb 2026 · github.com

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