Bhatti – Self-hostable Firecracker orchestrator with auto pause/wake

Name: Bhatti – Self-hostable Firecracker orchestrator with auto pause/wake
Availability: InStock
Author: sahil-shubham

by sahil-shubham·May 3, 2026·19 points·4 comments

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AI Analysis

●●●●GemZero to OneWizardrySolve My Problem

Idle VMs snapshot to disk and wake in 3.7ms, making serverless VMs actually viable.

Strengths

•Full system snapshots capture open file descriptors and TCP connections for true stateful pausing.
•Automatic thermal management transitions VMs from hot to warm to cold without user intervention.
•Detailed decisions page explains vsock state restoration and ARP retransmit tricks transparently.

Weaknesses

•Requires KVM access and root privileges for daemon installation, limiting shared hosting use.
•Firecracker overhead might be overkill for simple stateless functions compared to lighter runtimes.

Post Description

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` — needs no root)

Site: https://bhatti.sh

Repo: https://github.com/sahil-shubham/bhatti

Decisions & learnings: https://bhatti.sh/docs/under-the-hood/decisions/