bhatti

Author here. Reposting because the first attempt didn't land. Spent the last few months trying every snapshottable-sandbox product on the market to run my own coding agents. sprites.dev came closest but was unstable enough that I'd wake up to broken sessions. Halfway into building my own, I realised the market is ~ten companies racing to be the managed-Firecracker layer, and a Hetzner auction box is $40/mo. If you're willing to run the orchestrator yourself, you don't need any of them. I now run my own agents on it, plus the rest of my engineering workflow. It's been the harness-engineering substrate I wanted, and owning the runtime means I own everything I build on top of it too. Repo: https://github.com/sahil-shubham/bhatti

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 after restore, why all snapshots are Full, the systemctl shim, the ARP retransmit trick. curl -fsSL bhatti.sh/install | sudo bash (sudo because the daemon needs /dev/kvm and sets up the Firecracker jailer + a bridge; the CLI-only install — pipe to plain `bash`

The point about VMs being the wrong shape because they’re tied to CPU/memory resonates hard. The abstraction forces you to pay for time, not work. I ended up buying a cheap auctioned Hetzner server and using my self-hostable Firecracker orchestrator on top of it (https://github.com/sahil-shubham/bhatti, https://bhatti.sh) specifically because I wanted the thing he’s describing — buy some hardware, carve it into as many VMs as I want, and not think about provisioning or their lifecycle. Idle VMs snapshot to disk and free all RAM automatically. The hardware is mine, the VMs are disposable, and idle costs nothing. The thing that, although obvious, surprised me most is that once you have memory-state snapshots, everything becomes resumable. I make a browser sandbox, get Chromium to a logged-in state, snapshot it, and resume copies of that ses

Nice work on Shuru — I remember looking at it when I was researching this space. You went with a Rust wrapper on Apple’s Virtualization framework right? I have been working on something similar but on top of firecracker, called it bhatti (https://github.com/sahil-shubham/bhatti). I believe anyone with a spare linux box should be able to carve it into isolated programmable machines, without having to worry about provisioning them or their lifecycle. The documentation’s still early but I have been using it for orchestrating parallel work (with deploy previews), offloading browser automation for my agents etc. An auction bought heztner server is serving me quite well :)

I've been building an open-source, self-hostable Firecracker orchestrator for the past month: https://github.com/sahil-shubham/bhatti (https://bhatti.sh) Still WIP, but the core works — three rootfs tiers (minimal Ubuntu, headless Chromium with CDP, Docker-in-VM), OCI image support (pull any Docker image), automatic thermal management (idle VMs pause then snapshot to disk, wake transparently on next API call), per-user bridge networking with L2 isolation, named checkpoints, persistent volumes, and preview URLs with auto-wake. Fair warning: the website is too technical and the docs are mostly AI-generated, both being actively reworked. But I've been running it daily on a Hetzner server for my AI agents' browser automation, and deploy previews. I'd love any feedback if you want to go ahead and try it yourself