HN Explorer

Show HN: Lightweight tool for managing Linux virtual machines (github.com)

144 points by ccheshirecat ↗ HN
hey guys. the other day i was migrating hosting providers and i just needed something not too heavy and convenient to spin up my backups for awhile and realised there is almost nothing out there. kimchi hasn't been updated for years and cockpit is heavy. so here's something i came up with in a couple hours because of a sudden urge, nothing fancy just basic creation with cloud init, lifecycle management and image/storage, but it's modern-ish and it compiles to a 8.4mb binary inclusive of the embedded web UI, CLI and API, and only dep is libvirt.

18 comments

[ 2.8 ms ] story [ 43.7 ms ] thread
k_bx
While I am using cockpit every time I need to remotely manage the machines, I couldn't get it to log me in via something other than user's login/password, which are not that safe, and it listens to 0.0.0.0 by default too.

So I have to ssh into machine, start cockpit service, use it, and then stop the cockpit.socket once I finish.

Would be great to have something which has its own users/passwords (to have strong password in bitwarden) and doesn't listen to 0.0.0.0 by default. If it's also lightweight – even better!

sergsoares
You can use a localhost Cockpit with SSH Port Forwarding.

> Configure Cockpit to listen only loopback/127.0.0.1[1]:

[Socket]

ListenStream= #This remove 0.0.0.0:9090 bind based on the docs

ListenStream=127.0.0.1:9090

> Execute in your machine a port forward with SSH[2]:

ssh -N -L 9090:127.0.0.1:9090 host@ip

> Then you can open localhost:9090 in your browser securely only using SSH (that is already part of your actual workflow).

[1]: https://cockpit-project.org/guide/latest/listen

[2]: https://coder.com/docs/code-server/guide#port-forwarding-via...

lioeters
I like the sound of it, especially the compact single-file executable with minimal dependency. Forgive me for my ignorance, I may not fit the target user profile - I'm not familiar with KVM, and have only occasionally used QEMU. I read briefly about Cloud Init when setting up Multipass for creating new Ubuntu VMs.

What is KVM? - https://www.redhat.com/en/topics/virtualization/what-is-KVM

Can this tool `flint` replace some uses of Docker? I'm curious if I can use it for local development purpose, or for running stuff in production like isolating applications.

  flint launch [image-name]

  Launch a new VM with smart defaults. Supports launching from images or templates.
Is there a registry of images, like OS versions? Or maybe it's more decentralized than that. It also sounds related to OCI (Open Container Initiative) format that Podman supports, and qcow2 images for QEMU.

Could you give a brief summary of what this tool enables, for a potential user who doesn't know much about KVM?

ironhaven
Quick summary of the technology is that there is two software parts for virtualization, the hypervisor and the virtual machine monitor.

First is the hypervisor that uses the hardware virtualization features of your cpu to emulate hardware interrupts and virtual memory paging. This part is usually buint into the operating system kernel and one will be prefered per operating system. Common ones are Hyper-V on Windows, Virtualization.Framework on Mac and KVM on Linux

With the kernel handling the low level virtualization you need a Virtual Machine Monitor to handle the higher level details. The VMM will manage what vm image mounted and how the packets in and out of the vm are routed. Some example of VMMs are QEMU, VirtualBox and libVirt.

Flint, the app being shown is a vibe coded web app wrapper around libVirt. On the bright side this app should be safe to use but it also does not do much beyond launching pre made virtual machines. As a developer the work you need to do is provide an Linux distribution (Ubuntu, etc), a container manager (Kubernetes, Docker) and launch your own containers or pre made ones from the internet (Dev Containers).

_1tem
The readme keeps using the word “manage” but what does it actually do? Does it create and start new VMs? Using dockerfiles? On the local host or other hosts? I don’t understand WTF this thing does.
hamdouni
This part of the readme may answer your questions :

# List your VMs

flint vm list --all

# Launch a new Ubuntu VM named 'web-01'

flint launch ubuntu-24.04 --name web-01

# SSH directly into your new VM

flint ssh web-01

# Create a template from your configured VM

flint snapshot create web-01 --tag baseline-setup

# Launch a clone from your new template

flint launch --from web-01 --name web-02

imiric
Hey, thanks for sharing. As someone who uses QEMU via rudimentary shell scripts, this looks interesting.

Unfortunately, I'm reluctant to trust a 26KLOC vibe-coded app[1] for something like this, so I'll pass.

But if a polished React/Next.js app, with a CLI, HTTP/WebSocket API, authentication, and libvirt integration, truly took you a couple of hours to produce, and it solves your problem, that's a commendable achievement. I'm not sure if I should be praising you or the LLM, but it's notable nonetheless.

[1]: https://github.com/ccheshirecat/flint/commit/eb90847db9da56c...

_el1s7
You forgot to credit the AI who helped you generate this project in a couple of hours ;)
todotask2
How do you mount host's folder? My search for a VM that will work with Vite which can detect file changes on the host, or there is not answer?

Tart VM is interesting but still have the same issue.

athrowaway3z
For something as simple as this, is next.js even worth it?

There is something to be said for it because LLM's having been trained on its structure, but I'm having decent success stripping out all dependencies except tsc.

nodesocket
Does it support scheduling of snapshots and keeping N versions of snapshots?
jauntywundrkind
It'd be cool to see a nice UI (like this) atop something a little better built out & defined like systemd-nspawn. Like Quadlet for containers, Nspawn for VMs is a nice base with tons of great capabilities & very standard management patterns. There's nice .nspawn files and drop ins, where config lies, and (semi) standard paths for mounts and machines. Having that stable standard base would raise my interest & confidence a lot.

This recent guide covers a ton of nitty gritty, down to baking your own vm images & doing everything by hand. But by half way through, it builda to using the nice machinectl cli that is the real meat of the experience. https://quantum5.ca/2025/03/22/whirlwind-tour-of-systemd-nsp...

paul_h
Oh,systemd-nspawn is very cool.
ccheshirecat
For clarity: Hypr Pte. Ltd. (UEN 202520273N), AS211747 HYPR-NET, is an infra-focused startup working on microVMs, virtualization, and novel approaches to infrastructure. We are independently managed and only active in the infrastructure space; other accounts or projects are unrelated.

Infuze was ours but has since been shut down so we can focus fully on our own architecture. There has never been any scam, nor anything remotely related to one.

The Show HN post about the lightweight VM manager is unrelated to any cloud business. It started as a quick personal tool and unexpectedly resonated with people, so I iterated on it the same day. It’s just a minimal Go wrapper around libvirt, not connected to our core work.

Nullence
While I like the layout and having a good UI for managing virtual machines this project lacks any security features at all.

Most notably, if you just set the auth cookie to "authenticated" you will have access to spin up as many VMs you like on any flint instance in the wild (08-09-2025).

As such this is an incredibly unsafe project to use. Probably because of the vibe coding :(

xk3
> almost nothing out there

If you use Ubuntu or Debian, multipass is pretty easy to use.

Otherwise QuickGet / QuickEmu