libguestfs

C2012–2026

libguestfs / libguestfs

libguestfs

library and tools for accessing and modifying virtual machine disk images.

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5Distinct people

43Mentions

0Explicit recommenders

752GitHub stars

REPOSITORY AT A GLANCE

What to know before exploring

What it is

library and tools for accessing and modifying virtual machine disk images.

GitHub

Where it is used

No documented product use has been verified yet.

What people are saying

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Also in these discussions

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This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:03:16 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year43 dated mentions

Observed mentions: 2012-02-14 11:50:14 UTC to 2026-06-10 11:06:16 UTC.

* An incomplete calendar period is marked with an outlined bar. Its count is not directly comparable with a full period.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges

UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
Period	Start (UTC)	End (exclusive, UTC)	Mentions	Submissions	Comments
2012	2012-01-01 00:00:00 UTC	2013-01-01 00:00:00 UTC	4	1	3
2013	2013-01-01 00:00:00 UTC	2014-01-01 00:00:00 UTC	2	0	2
2014	2014-01-01 00:00:00 UTC	2015-01-01 00:00:00 UTC	3	0	3
2015	2015-01-01 00:00:00 UTC	2016-01-01 00:00:00 UTC	9	0	9
2016	2016-01-01 00:00:00 UTC	2017-01-01 00:00:00 UTC	8	0	8
2017	2017-01-01 00:00:00 UTC	2018-01-01 00:00:00 UTC	4	0	4
2018	2018-01-01 00:00:00 UTC	2019-01-01 00:00:00 UTC	2	0	2
2019	2019-01-01 00:00:00 UTC	2020-01-01 00:00:00 UTC	3	0	3
2020	2020-01-01 00:00:00 UTC	2021-01-01 00:00:00 UTC	1	0	1
2021	2021-01-01 00:00:00 UTC	2022-01-01 00:00:00 UTC	1	0	1
2022	2022-01-01 00:00:00 UTC	2023-01-01 00:00:00 UTC	2	0	2
2023	2023-01-01 00:00:00 UTC	2024-01-01 00:00:00 UTC	2	0	2
2024	2024-01-01 00:00:00 UTC	2025-01-01 00:00:00 UTC	1	0	1
2025	2025-01-01 00:00:00 UTC	2026-01-01 00:00:00 UTC	0	0	0
2026 (partial)	2026-01-01 00:00:00 UTC	2027-01-01 00:00:00 UTC	1	0	1

What Hacker News says

43 sources

zelphirkalt·Jun 10, 2026

You mean this one: https://github.com/libguestfs/libguestfs/blob/master/Makefil... ? I don't see how ocamldep is used in there. It seems to use multiple different programming languages somehow. I don't find it easy to understand what it does. It seems to be building a website as well.

In OCaml Onboarding: Introduction to the Dune build system

rwmj·Apr 2, 2024

We started off doing this, but you end up with enormous diffs which are themselves confusing. Example, only about 5% of this change is non-generated: https://github.com/libguestfs/libguestfs/commit/5186251f8f68... Probably depends on the project as to whether this is feasible, but for us we intentionally want to generate everything we can in order to reduce systematic errors.

In From xz to ibus: more questionable tarballs

rwmj·Oct 6, 2023

The internal version number is still Windows 10. Edit: some references: https://github.com/libguestfs/libguestfs/commit/824c74574893...

In Microsoft might want to be making Windows 12 a subscription OS, suggests leak

rwmj·Apr 27, 2023

And inside the registry. The apparently correct way to distinguish them is using the build ID: https://github.com/libguestfs/libguestfs/commit/824c74574893...

In Microsoft: Windows 10 22H2 is the final version of Windows 10

rwmj·Nov 16, 2022

A warning that while there's something called sysconfig that replaces distutils.sysconfig, it is not compatible: https://github.com/libguestfs/libguestfs/commit/26940f64a740...

In Python 3.12.0 is to remove long-deprecated items

rwmj·Apr 14, 2022

I've used both quite extensively and I think that Coverity is still better, but GCC's static analysis is the closest free tool I've found that is doing the kind of complicated dataflow analysis that Coverity does. In GCC 12, compared to GCC 10/11, it got a whole lot more "aggressive", to the point where it's no longer possible to compile the kernel with warn-error because of many static analysis warnings in core code, and I also had to rearrange and annotate [to disable some warnings] a lot of code in my own projects to get things to compile. So next time you compile some C code with GCC 10, 11 or 12, definitely try -fanalyzer to see what it says, but be warned that you might be presented with some complicated error messages which require quite a lot of time to analyse to see if they're real problems or false alarms. Here are some genuine

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problems found: https://github.com/libguestfs/libguestfs/commit/58599031f849... https://github.com/libguestfs/libguestfs/commit/8dd09a16f59c... Here are some false alarms: https://github.com/libguestfs/libguestfs/commit/ea04d6b878ec... https://github.com/libguestfs/libguestfs/commit/d00c36410b74... https://github.com/libguestfs/libguestfs/commit/9dddd8ec62d5... https://github.com/libguestfs/libguestfs/commit/8a4275c5686d... Edit: In Coverity's favour, it supports many more languages than just C/C++

In The state of static analysis in the GCC 12 compiler

rwmj·May 9, 2021

We have 6 lines of code that we copy and paste around projects: https://github.com/libguestfs/libguestfs/blob/d01ce082180c41... Now if you're saying that the autotools/make/cmake/meson tooling is hard, I sort of agree, but many people are familiar with C build tools already. I don't see how it's easier or harder than learning language-specific tools.

In OCaml is 25

rwmj·May 20, 2020

(Part time libvirt developer here ...) I argued early on for libvirt to model things properly through a C API. Obviously I didn't succeed. I eventually wrote a bunch of "interesting" C macros to make it easier to create and submit XML documents: https://github.com/libguestfs/libguestfs-common/blob/master/... Example usage: https://github.com/libguestfs/libguestfs/blob/b9065fa7adc931... However these days when just about everything is a service accessed by shuffling poorly documented and type-unsafe JSON documents over the network, maybe libvirt was just ahead of its time ... [Libvirt XML is incredibly well documented, probably in some ways over documented.]

In KVM host in a few lines of code

ernst_klim·Dec 23, 2019

> Ocaml - the functional approach is not for everyone. OCaml is pretty general purpose though, it has loops, objects, mutable state. libguestfs [1] and some other codebases (the compiler itself, btw) are written in a pretty imperative OCaml. [1] https://github.com/libguestfs/libguestfs

In Lilith: x86-64 OS written in Crystal

rwmj·Jul 9, 2019

I'm involved in a couple of projects which do a lot of metaprogramming to generate boilerplate. The generated code is usually C. For the generator I wouldn't recommend using CPP or M4, use a real programming language instead. I'm using OCaml since ML discriminated unions are a good fit for generating code, but other languages would work too. It's a fantastic technique which greatly reduces bugs, speeds development and eases maintenance. Here are links to the generators for those projects: https://github.com/libguestfs/libnbd/blob/master/generator/g... - This is a small C library. It uses a small-ish generator to generate a state machine, Python bindings, OCaml bindings and (patch coming soon) Rust bindings. https://github.com/libguestfs/libguestfs/tree/master/generat... - This is a very large project mostly written in C, using a gene

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rator to generate bindings in multiple programming languages, also RPC boilerplate, structures, configuration code and much more. This generator is very large having evolved with the project over 10+ years. Edit: Some rules for effectively generating code: (1) The generated code must look as far as is reasonable like it was hand written. This is because you'll be debugging it. We also use #line directives where possible. (2) chmod -r the generated files so they cannot be edited by accident. Also add a comment at the top pointing to the generator so that developers who have no idea how it works can immediately find the right place. (3) We add the generated files to the tarball (to allow end users to build without needing OCaml) but keep them out of git (to avoid duplication in commits). (4) Maximum generation! If some piece of information is written twice, it should probably be written once (in the generator) and the output should go to those two places. Similarly we only have one generator in the project so no one needs to read the Makefiles to find out how a file is generated.

In The Art of Metaprogramming (2005)

rwmj·Mar 3, 2019

That's pretty much how we wrote the virt tools[1], basically we rely on the OCaml compiler, findlib, and not much else. [1] https://github.com/libguestfs/libguestfs

In Functional Programming in OCaml

rwmj·Nov 19, 2018

ocsigen does this for OCaml: https://ocsigen.org/eliom/1.3.4/manual/html The syntax is fairly lightweight, just << followed by valid, type checked XHTML ended by >>. There are also antiquotations so you can use it as a templating language. For those of us generating XML from C I wrote a hairy set of C macros: https://github.com/libguestfs/libguestfs/blob/master/common/... so you can write code like this (which is not fully checked at compile time of course): https://github.com/libguestfs/libguestfs/blob/4aa712d551f9d4...

In Typed-Html: Type Checked JSX for Rust

rwmj·Aug 28, 2018

Fun fact: qemu (actually the sgabios in qemu) sends the ESC [ 6 n sequence to query the terminal and waits for 0.26 seconds for a response before timing out. In libguestfs I added code to "answer" this query, to shave 260 milliseconds off boot times: https://github.com/libguestfs/libguestfs/blob/0d0b5511309182...

In SCI and the “62;c62;” attack

rwmj·Dec 28, 2017

I couldn't get to the site, but assuming this is running Linux I wrote a paper about how fast you could boot a Linux minimal userspace on QEMU a couple of years ago[1]. In short if you're willing to heavily customize the kernel, qemu and userspace then you can get it down to 100-150ms on i7-type hardware, but probably not much lower. Using a distro kernel, distro qemu and so on, you're stuck with 400-600ms (which is fine for certain uses, eg better security for containers like Kata Containers is doing). Also worth noting I wrote a bunch of benchmarking tools to help optimize this case[2]. [1] http://oirase.annexia.org/tmp/paper.pdf [2] https://github.com/libguestfs/libguestfs/tree/master/utils

In Zerg: Boot a VM instance per request, all in under 250 ms

rwmj·Jul 31, 2017

Is there a problem generating them? It's essentially just a single ‘ssh-keygen’ command, see eg: https://github.com/libguestfs/libguestfs/blob/master/p2v/Mak...

In Google Search: Inurl:server Filetype:key “-----BEGIN RSA PRIVATE KEY-----”

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