GNU Guix 0.8.1

Reminds me of archlinux early days when one of their main arguments was that configuration was done in a single file (as BSDs). Nix is like a typechecked version of that.

I'm one of the developers, but my first experience before that was installing it on top of my Debian system. There were a few manual setup steps to follow to make it work, but once it did it was awesome. Guix lives perfectly alongside a host system like Debian and doesn't interfere with apt. Guix packages, while being fewer in number, are more up-to-date, so I used Guix to get versions of software that weren't in Debian yet.

Installing the full OS is for the brave at the moment, but we'd certainly like you to give it a try if you have the machine/VM to spare. If you do, please let us know what you liked/disliked, what worked and what blew up. There's no guided installer, but it's not too hard to get running in most cases. Partition disks, write system config, run something like 'guix system init config.scm /mnt/my-new-root-partition/' and reboot.

Since becoming one of the core developers, I have been working on a tool called 'guix environment' that can be used for creating reproducible development environments for software projects. I was happy to discover that the core part of Guix contains all the features needed to write tools that could replace things like Vagrant and (once we have container support) Docker. It's just a matter of writing the proper frontend.

I hope you'll give Guix a try sometime. :)

I ran Guix as user-specific overlay on my Gentoo box for some time. It was pretty neat and I thought about using it for cross-distro deployment of libraries I need for development.

About half a year ago I ran into problems with updating and did not have the time to fix it (stuff simply did not build - I did not try the --with-source trick).

I hope that a reinstall with the new version fixes that.

What sold it to me was that when the system breaks during update, everything is still in a working state. → http://draketo.de/light/english/install-gnu-guix-03 My son once found the power-connector of my Gentoo box while I was running updates and hit the pretty red glowing button. It took me three days to recover the system…

My experince is running it in a VM and getting really strange scheme-like errors from guix command-line-tool, then giving up. I think I managed to install it once to a virutal-harddrive, but then grub2 was a disaster and the "system" did not boot. Oh well.

I've been using Guix for about a week and it's mostly worked for me. I'm not sure why but sometimes `guix package -i <pkg>` will fail yet I can do a `guix build <pkg> [--with-source=<src>] ; guix package -i <pkg>` and the package will then get installed as expected. (I've only had to use the `--with-source` option once, and it was with openssl, iirc, because the tar.gz guix was looking for was no longer in openssl's ftp site at `/source/openssl<ver>.tar.gz` instead it was moved to `/source/old/openssl<ver>.tar.gz`)

But in general I have no idea what I'm doing with it. Just trying it out and it's mostly working for me.

From my understanding, the biggest disadvantage to purely functional package management is that you can't just swap out a package in isolation when many others depend on it. If I upgrade a package, I have to upgrade its whole DAG of dependent packages if I want them to use the new version (I could however delay that; they would simply continue to use the old version which hasn't been garbage-collected yet because they still use it).

So lots and lots of compilation (on build farms at least), and lots of bandwidth usage. Though something like ccache can help with the compilation, and binary diffs could help with the bandwidth.

Immutable data structures in FP are probably a good analogy.

Edit: argh, this was supposed to be a reply to the question about the disadvantages of the purely functional package managers specifically, not the OS in general.

The learning curve is pretty steep. It's not just a new config language, it's also letting go of many preconceptions one may have (where stuff lives on the filesystem e.g.).

That's also true for software I'm packaging. Certain ecosystems just really love to load configuration files and write log files relative to the binary path which breaks in nixos because all packages live on a read-only mount (looking at you ruby, cargo from rust will also be fun).

Lastly there's just not the same number of contributors yet so you're going to have more of the small issues that get fixed and reported by the armies of users that e.g. Ubuntu has.

I'm saying all this as an incredibly happy user. I can think of few technologies that have given me as much leverage as nixos in recent years.

A disadvantage is that some services (like dbus) look for service files in a well-known location. When packages are installed they don't place any of their files in a directory outside of their target directory. So, JACK2, for example, won't be able to place its dbus service file in a location that the dbus service natively knows about.

In many cases situations like this can be fixed by setting environment variables, but in some cases more patching is required to make this work properly.

EDIT: I don't consider this a serious disadvantage, though. It is not unusual for packagers to patch software in other distributions. (I dare you to check out spec files for popular RPMs.) It's just something a package maintainer has to think about under some circumstances.

I should also note that I'm surprised at how little patching is required for most software (besides the common shebang patching).

1. There are few packages, compared to dpkg.

2. It creates guix-specific users for building purposes.

There really isn't much bad to say about guix. You can even switch to it without giving up on your old package manager. That way, even point 1. isn't an issue. Of course, 2. isn't really an issue in itself; `cat /etc/passwd` already contains a lot of users whose purpose I know little about.

First of all: Guix (and Nix) seems like really interesting projects, I'm just not there yet that I'm going to nuke what I know and love for it.

I probably will one day, but not right now.

But: I'm not sure you're doing your work any justice by labelling it "avant-garde". I think you risk looking "weird" or more dangerous than you need to and might detract people from looking into it.

Guix is based on Nix, so the following applies to both.

apt-get allows at most one version of a package to be installed at a time; if you want two versions, you need to ask the maintainers to split the package into two. Guix doesn't suffer this problem; packages are given an ID based on a hash of their contents and dependencies, so two versions will happily sit side-by-side. An "update" is treated more like installing a separate package.

If two applications depend on two different versions of some library, you can't install both applications. In Guix you can, since each can use the version it needs.

apt-get affects the whole system. All users are affected by a change; if some other user installs/removes/updates a package, you have to just deal with it. In Guix, every user gets a "profile" package, which can depend on anything they like. Installing/removing/updating packages just creates a new version of your profile, with its dependencies added/removed/changed according to what you asked for.

apt-get is stateful: the contents of /usr, /etc, etc. are changed as packages are installed/removed. Guix is immutable: packages live in their own read-only directories, so nothing can break them after installation.

apt-get can't roll back: packages can't be down-graded, all kinds of actions are taken by pre/post install scripts which can't be undone, etc. Since Guix is immutable, "rolling back" just means going back to the old selection of packages; ie. installing the old version of the profile package.

Both Guix and Nixos allow your system to be defined declaratively. This means that the details of reproducing your system state, given a declarative configuration, are fully handled by Guix/Nixos. So, if you like, you can consider the mapping between declarations and systems a pure function (i.e. you always get the same startup state for a given config). It's not hard to see how this could be valuable when deploying many servers (reproducability), getting out of dependency hell / failed upgrades (perfect rollbacks), bug reporting (just append the config that fully describes your system!), etc...

I've also found that the increasing entropy caused by stateful alternatives (e.g. apt-get) eventually becomes impossible to manage. This is entirely due to hidden state that grows in complexity over time. Eventually, things break in a way that nobody on StackOverflow has seen before, and you're SOL. In the declarative world, everything specific to your setup is required to be defined upfront, in one central place. This provides you with a much better chance of understanding your system as it evolves.

(Your account name makes me think you've appreciated functional programming data structures at some point. In not surprisingly, the benefits of immutability and declarative style in programming languages seem to carry over to configuration management.)

Others have explained it, but I like to see it like that:

- apt-get, yum, pacman and "traditional" package managers deal with _transition of your system_: _please install this packet_, _please remove this packet_

- nix and guix deal with _state of your system_: _please make sure that the final state is thus_.

This brings easy reproducibility of a system (if you have the recipe, you can have a another machine be an _exact_ copy) and de-entanglement (no more managing conflicting dependencies, no more dangling files). If I were to draw parallel, it would be like this:

- "traditional" package managers are like jQuery: you pick some DOM node / some package, and modify it / update it. After some time you don't know anymore who modified this DOM node, who needs it, ... things become hard to track

- nix and guix are like React: you specify the state you want in a single place (or rather in a definite place) and React/nix maps that definition into your final product

Here's a long blog post that goes into more detail: https://www.domenkozar.com/2014/03/11/why-puppet-chef-ansibl...

apt-get can not install the same package/software in many different versions, there is always some package conflicts happening and you cant describe the state of your desired system with any "apt-get" language. You must script your desired state manually or use puppet or chef or whatever, which will perform the steps/tasks that you desire on your system using multitude of software and languages.

With guix gsd and nixos, the package manager is the configuration manager. The package manager is not just package manager, its not just apt-get, it is also puppet/chef/salt, and a distribution-maker or manager. I believe with guix you could make your own distribution (software collection) in the same descriptive language as making packages. You cant do that with apt or any debian tools.

Don't know about Guix, it seems to be inspired by/similar to Nix. As far as I understand, the advantage of Nix is that it's a stateless description of the system, so the advantages are:

* you can describe a tree of dependencies using any version of the package you want, and can easily rollback to a previous tree if an update broke it

* because you describe a tree of packages, you're actually describing the complete state of the system, there's no leftovers from previous installations which make it work by chance

* as a result you can easily partially alter (and rollback) or move nix configurations from one machine to the next

Essentially nix (and guix?) merges package management and configuration management in a stateless and declarative, easily audited and customised, manner.

It's better because given the same input you always get the same output. For example, in Gentoo when one builds a package the final result depends on what's been built before. Or (killer feature for configuration management):

Suppose one has a resource for file in Puppet

file "blah" do source "yada" end

if you erase that resource, the file still stays there. With Nix/Guix anything not defined in configuration isn't present at all on system.

Another feature : one can install, for example, different versions of Python/PyPy/etc locally using the same package manager. Local and system-wide package share the same underlying files and don't interfere.

Rollbacks, very easy way to restore system packages/configs to previous working state.

Very interesting your responses. Looks interesting to try it. So it's hard / too problematic to get it working over, a Kubuntu ?

that sounds pretty cool!

I tried using Guix to deploy to the cluster in Karlsruhe (more than a year ago) but back then it was still missing most of the libraries I needed. When you finished making it work for your cluster, that could be a pretty good base for many other people, too.

this brings to mind the justification behind the SciPy distribution. I wonder if nix or something based on it has the potential to be used as a more generalized replacement for thinks like virtualenv? Just roll up a new user for your project with all the dependencies defined, instead of the kinda-sorta isolation of a venv and without the overhead of a vm?

One disadvantage compared to RPM and apt-get is that there are not as many packages available yet.