this post was submitted on 14 Feb 2024

104 points (97.3% liked)

Linux

48330 readers

639 users here now

From Wikipedia, the free encyclopedia

Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.

Rules

Posts must be relevant to operating systems running the Linux kernel. GNU/Linux or otherwise.
No misinformation
No NSFW content
No hate speech, bigotry, etc

Related Communities

Community icon by Alpár-Etele Méder, licensed under CC BY 3.0

founded 5 years ago

MODERATORS

[email protected]

104

Nix/Silverblue users: How big is the advantage if you already have 100% automated your deployments via Ansible? (self.linux)

submitted 9 months ago* (last edited 9 months ago) by wolf to c/[email protected]

54 comments fedilink hide all child comments

There is a similar question on the site which must not be named.

My question still has a little different spin:

It seems to me that one of the biggest selling points of Nix is basically infrastructure as code. (Of course being immutable etc. is nice by itself.)

I wonder now, how big the delta is for people like me: All my desktops/servers are based on Debian stable with heavy customization, but 100% automated via Ansible. It seems to me, that a lot of the vocal Nix user (fans) switched from a pet desktop and discover IaC via Nix, and that they are in the end raving about IaC (which Nix might or might not be a good vehicle for).

When I gave Silverblue a try, I totally loved it, but then to configure it for my needs, I basically would have needed to configure the host system, some containers and overlays to replicate my Debian setup, so for me it seemed like too much effort to arrive nearly at where I started. (And of course I can use distrobox/podman and have containerized environments on Debian w/o trouble.)

Am I missing something?

top 50 comments

sorted by: hot top controversial new old

[–] [email protected] 30 points 9 months ago (2 children)

In this comparison, the devil is in the detail.

With Ansible, you have an initial condition onto which you add additional state through automatically executed steps dictated by you until you (hopefully) arrive at a target state. This all happens through modification of one set of state; each step receives the state of the previous step, modifies it and passes the entire state onto the next step. The end result is not only dependant on your declared steps but also the initial state. A failure in any step means you're left in an inconsistent state which is especially critical for the case of updating an existing state which is the most common thing to do to a Linux system.

In NixOS, you describe the desired target state and the NixOS modules then turn that description into compartmentalised bits of independent state. These are then cheaply and generically combined into a "bundle"; wrapping them into one big "generation" that contains your entire target state.
Your running system state is not modified at any point in this process. It is fully independent, no matter what the desired system is supposed to be. It is so independent in fact that you could do this "realisation" of the NixOS system on any other system of the same platform that has Nix installed without any information about the state of the system it's intended to be deployed on.
This "bundle" then contains a generic script which applies the pre-generated state to your actual system in a step that is as close to atomic as possible.
A good example for this are packages in your PATH. Rather than sequentially placing the binaries into the /usr/bin/ directory as a package manager would when instructed by ansible to install a set of packages, NixOS merely replaces the bin symlink with one that points at an entirely new pre-generated directory which contains the desired packages' binaries (well, symlinks to them for efficiency). There cannot possibly be an in-between state where only some of the binaries exist; it's all or nothing. (This concept applies to all parts that make up a Linux system of course, not just binaries in the PATH. I just chose that as an easy to understand example.)
By this property, your root filesystem no longer contains any operating system configuration state. You could wipe it and NixOS would not care. In fact, many NixOS users do that on every boot or even use a tmpfs for /.

(Immutability is a property that NixOS gains almost by accident; that's not its primary goal.)

[–] [email protected] 4 points 9 months ago (1 children)

Very good explanation. It's an often overlooked property of NixOS and why I often feel like Nix on other systems is an okay way to get packages but you're missing out on all the good stuff you get through the modules, like losing 95% of what makes the concept good.

I don't think NixOS is the best possible solution to the problem, but it's the only original distribution that even tries to tackle it instead of just working around it.

[–] [email protected] 2 points 9 months ago (1 children)

it’s the only original distribution that even tries to tackle it instead of just working around it.

Well, apart of GUIX of course ;)

It's sort of a conceptual fork of Nix but the actual implementation is all original.

[–] [email protected] 2 points 9 months ago (1 children)

I thought so too but learned recently that Guix system is nix under the hood, basically translates everything, so it's more than a conceptual fork though obviously some more work went into it than your average Ubuntu fork.

It uses low-level mechanisms from the Nix package manager, but packages are defined as native Guile modules, using extensions to the Scheme language—which makes it nicely hackable.

https://guix.gnu.org/en/about/

[–] [email protected] 2 points 9 months ago* (last edited 9 months ago)

They used to use the nix-daemon to realise derivations but that too was replaced original software at some point I believe. Everything else has been guix own tooling for a long time.

They still use the same derivation file format (.drv) and the basic concepts are the same ("conceptual fork"), so you could theoretically be able to realise a derivation produced by guix using nix-daemon/nix-store but that's about it as far as similarities go.

If you don't believe me, go take a look at the source code. I promise you won't find a single line of C++ in it, only a ton of parenthesis ;))))

[–] wolf 1 points 9 months ago (1 children)

Nice, thank you very much for this great summary!

In my own words, you describe the difference between declarative vs. imperative configuration and the joy of atomic updates. :-)

I just want to add one point: Theoretically I totally agree, that one might have a bad state in Ansible and the updated state is spoiled, and of course configuration drift is a theoretical problem via Ansible. In practice I never run into this problems in 10+ years of using Ansible. (Of course I treat servers/desktop as cattle, so every major revision of Debian means a complete/clean new installation.)

[–] [email protected] 2 points 9 months ago (1 children)

If it works for you, that's great.

I find it a lot more convenient to treat every change about my system as a nearly complete/clean new installation though and NixOS allows you to do so. An upgrade between major versions becomes a walk in the park due to this; it's the M.O. The last one didn't require any modification of the config on my NAS. I remotely rebuilt the system from my MacBook Pro with the new channel, rebooted to get the newer kernel and everything worked just like before.

[–] [email protected] 1 points 9 months ago (1 children)

An upgrade between major versions becomes a walk in the park due to this

For personal desktop use, I see nixos and guixos as spending an hour every day, so that you can save minutes every few years.

When trying out guixos, I spent like 5 days going through the docs and annoying people on irc, just to accomplish the same thing as copying a file to a non-~ directory in a normal distro. Anyways, I powered through the weeks of configuration, and got to actually doing some work in the damn thing. I started off by using the language specific PM to install the dependencies I needed for a project. Welp, guix is not FHS compliant, and can only stand the presence of isolated PMs like nix and flatpak, so that's out of the question. Since the guix packages were too old, it was time to either:

maintain my own guix definitions of random packages + their dependencies, and then maintain a separate source of dependencies for the project
learn how to nix and then maintain a separate source of dependencies for the project
start figuring out how to use guix to emulate FHS inside of a venv

So I obviously went for the third option, gave up after banging my head some more, and finally nuked the partition.

aint nobody got time for that

Recently I started using home-manager, and tried converting my i3 config so it's handled by it. Halfway through, it set in just how ugly the syntax looks. I mean just look at a small part from the beginning of both files: nix formatted by nixfmt, i3 config. But ok, I might get used to it, let's test it out: it fucking added defaults like the keybindings I've specifically removed from the config so that the only two i3 deals with are opening the terminal and reloading itself. Then I finally realized I'm wasting my time creating this monstrosity, when literally the only benefit is that it would allow me to skip symlinking directories after a fresh install. So now it's only managing my packages, doing a great job freshening up stable Debian, and I can reload any config immediately after saving the file instead of going through the entire process of recreating everything home-manager handles.

I might still use it for some specific packages, like firefox (about:config and custom css), which can't really be stowed easily.

Nix and Guix os are brilliant in specific use cases they were made for, like when you're creating a large number of ephemeral instances for scientific computing and need extremely precise control of everything that goes into the image. Spending a week to configure something simple is worth it in that scenario because it'll save you from much bigger headaches down the line. The issue is that they solve problems most users simply don't face, and so the added complexity comes with practically no benefits.

[–] [email protected] 2 points 9 months ago (1 children)

I see nixos and guixos as spending an hour every day, so that you can save minutes every few years.

I see it more like spending an hour every week so that you can save hours to days of annoying and stressful time every few months.

Though there are other benefits rather than just time.

When trying out guixos, I spent like 5 days going through the docs and annoying people on irc, just to accomplish the same thing as copying a file to a non-~ directory in a normal distro

In the beginning when you're not familiar with things yet, it always takes more time to do something.

I didn't have that particular use-case yet and I'd have to consult at least one manual to do it correctly but I'd nowadays be able to solve that particular problem with one line of relatively simple code in NixOS. (On Guix, I don't know how I'd do it though since they don't use systemd.)
When I started out though? No chance, it'd have taken weeks.

I started off by using the language specific PM to install the dependencies I needed for a project.

Yeah, that's like mistake #1 for non-FHS-compliant distros. ;)

start figuring out how to use guix to emulate FHS inside of a venv

As the person who implemented a variant of this for Nix (buildFHSEnv), it's rather straight-forward. Though if it didn't exist, I'd rather try distrobox or other dev container thingies if there was no reasonable nix support for the thing I'm working on.

I mean just look at a small part from the beginning of both files: nix formatted by nixfmt

I mean, that's just one particular interface. It's actually quite flexible to do it this way though as it allows you to dumb it down if you don't like it with a little refactor:

{
  startup = let
    exec = command: {
      inherit command;
    };
  in [
    #on launch
    (exec "emacsclient -a '' -nc --init-directory=~/.config/emacs" // {
      workspace = "1";
    })
    (exec "nitrogen --restore")
    (exec "~/.screenlayout/shareni.sh")
    (exec "numlockx on")
    (exec "volumeicon")
  ];
}

That's the beauty of IaC (actual code, not that YAML nonsense): Software environment configuration becomes a software engineering problem and we know how to solve those.

In this specific case though, I probably wouldn't bother with doing that stuff in Nix and would rather just keep the plain i3config text file and set the option glue to just use that file; effectively a glorified stow.

This more complex interface is only truly beneficial if there are parts of your config that vary depending on some other conditions. Some users may have the need to only run a set of commands or have certain launch options on one machine but not another. Trivial to do with lib.optionals and the like using this kind of interface but very hard to do if it was just a list of strings or one large string.

it fucking added defaults like the keybindings I've specifically removed from the config so that the only two i3 deals with are opening the terminal and reloading itself

Well, then tell it to not to do that? I don't know the module in question but any well-designed module has an option for precisely that. If it doesn't, I'd consider that a bug. Otherwise, lib.mkForce is usually also an option.

Spending a week to configure something simple is worth it in that scenario because it'll save you from much bigger headaches down the line. The issue is that they solve problems most users simply don't face, and so the added complexity comes with practically no benefits.

I wholeheartedly disagree. Declarative stateless system configuration a la Nix solves a lot of issues that users face all the time.

Whether the time investment is worth it at present is debatable but there's a clear path towards yes IMO because a project focused around proper IaC elevates operating systems onto another level because it abstracts and centralises configuration. It takes one person to figure out how to configure a certain thing in a sensible way and they can publish that work as a NixOS module for everyone's benefit. Most of the work I put into NixOS is upstream because of this.

Right now, it's absolutely catered towards nerds and other technologically able people like us but imagine what a further abstracted GUI could do for mere mortals.

[–] [email protected] 1 points 9 months ago (1 children)

Thanks for the detailed response.

I’d nowadays be able to solve that particular problem with one line of relatively simple code in NixOS

I can't remember the exact details of the whole issue, but that part was for a desktop entry. If I remember correctly, in the end I had to create a system service and there were no readily available examples like for the packages. After days of researching in my spare time, I had to ask in the irc for a snippet from someone's config.

As the person who implemented a variant of this for Nix (buildFHSEnv), it’s rather straight-forward.

Oh, it seems really cool. I'll need to look into it.

I mean, that’s just one particular interface. It’s actually quite flexible to do it this way though as it allows you to dumb it down if you don’t like it with a little refactor:

That's definitely an improvement, but the default config is still far better IMO.

I probably wouldn’t bother with doing that stuff in Nix and would rather just keep the plain i3config text file and set the option glue to just use that file; effectively a glorified stow.

Replacing stow with home-manager has the same issues as replacing a regular distro with nixos. If I can stow all of my dotfiles, why would I use home-manager to handle them instead? In most cases it's just going to be harder to configure anything, and you also need to rebuild your home every time you want to update a config.

This more complex interface is only truly beneficial if there are parts of your config that vary depending on some other conditions. Some users may have the need to only run a set of commands or have certain launch options on one machine but not another. Trivial to do with lib.optionals and the like using this kind of interface but very hard to do if it was just a list of strings or one large string.

What benefits does it have over just using a shell script?

I guess it's also great for programs that aren't following the standards like firefox.

Well, then tell it to not to do that? I don’t know the module in question but any well-designed module has an option for precisely that. If it doesn’t, I’d consider that a bug.

It's probably a skill issue, but that ties into another problem I've had when messing around with home-manager: the only source of options I found was mynixos. So to configure anything I had to first guess potential keywords to search for the option I'm interested in. And that's after learning about it from some video on youtube, because google left me high and dry.

I wholeheartedly disagree. Declarative stateless system configuration a la Nix solves a lot of issues that users face all the time.

Can you give me some examples, what issues will I face running MX + nix that I wouldn't if I ran nixos?

As someone who works with terraform, I understand the benefits of being forced to keep a single source of truth instead of remembering to update my post-installation script and keep things synced across devices. But on the other hand this is everything I need to do to get a fresh install to where I'm currently at:

install the single docker dependency that doesn't work with home-manager
clone my dotfiles and symlink them
set up nix, home-manager, and switch
remove the few packages I've replaced with nix ones
cp the i3.desktop (home-manager and sddm were not agreeing)
clone and install doom

It's definitely not a lot to maintain, and the issues are either obvious and easy to solve, or just a small waste of space. For example if I forget to remove the debian version of git, it's still going to automatically source the nix one first. Home-manager with just a list of packages makes the hardest part of that process a breeze, while still being really easy to set up.

The main problem was getting started from 0, so I'm considering writing a post about it when I get a bit more comfortable. Trying to learn nix declarative package management from the nix manual is a bad idea, and almost all of the resources are on nixos. A quickstart guide with a few commands and examples would've had me up and running in 10 minutes instead of days.

Whether the time investment is worth it at present is debatable but there’s a clear path towards yes IMO because a project focused around proper IaC elevates operating systems onto another level because it abstracts and centralises configuration. It takes one person to figure out how to configure a certain thing in a sensible way and they can publish that work as a NixOS module for everyone’s benefit. Most of the work I put into NixOS is upstream because of this.

Right now, it’s absolutely catered towards nerds and other technologically able people like us but imagine what a further abstracted GUI could do for mere mortals.

Oh for sure, a home-manager gui that let's you customize every package from a single place while automatically updating your config would be a complete game changer. But I'm talking about the current state of things. In that regard, currently every linux user can enjoy simple declarative package management with stable and bleeding edge sources. Yet I never see it mentioned, while even beginner threads are being spammed with nixos recommendations. Imagine if casuals could open their software center or discover and install nix packages instead of flatpaks.

[–] [email protected] 2 points 9 months ago

If I can stow all of my dotfiles, why would I use home-manager to handle them instead? In most cases it's just going to be harder to configure anything, and you also need to rebuild your home every time you want to update a config.

Yes, yes indeed. That's why my dotfiles are still in a git repo (don't get the point of stow), not in home-manager.

If you do in fact need home-manager's features for some of your dotfiles though, it can effectively act as a stow superset for the rest.

What benefits does it have over just using a shell script?

Declarative stateless configuration rather than imperative stateful configuration.

With a bash script, you'd have to meticulously craft together the i3config file using shell script syntax and remember to run that every time you change something. home-manager just does all of that for you with high-level data types and frameworks specifically made for that purpose.

that ties into another problem I've had when messing around with home-manager: the only source of options I found was mynixos. So to configure anything I had to first guess potential keywords to search for the option I'm interested in.

Yeah, it's not great. https://search.nixos.org/options? is really useful for NixOS.

You have to either use your browser's dumb search on https://nix-community.github.io/home-manager/options.xhtml or your pager's dumb search in man home-configuration.nix.

Can you give me some examples, what issues will I face running MX + nix that I wouldn't if I ran nixos?

All the issues which declarative immutable stateless system configuration solves such as atomic updates, configuration rollback in case you messed something up and trivial recovery. I'm sure I'm forgetting some since I'm so used to having them.

The main problem was getting started from 0, so I'm considering writing a post about it when I get a bit more comfortable. Trying to learn nix declarative package management from the nix manual is a bad idea, and almost all of the resources are on nixos. A quickstart guide with a few commands and examples would've had me up and running in 10 minutes instead of days.

Yeah, docs are a pain point. If you think that section is bad (I think so too), everyone will thank you for rewriting it. Feel free to shoot a PR to Nixpkgs and ping a few people from the docs team if you're motivated.

Yet I never see it mentioned, while even beginner threads are being spammed with nixos recommendations.

I don't get it either. NixOS is the best thing since sliced bread for a certain kind of person (experienced hacker who has felt the pain points which NixOS relieves) but I'd never recommend it to an inexperienced user in its current state.

[–] [email protected] 28 points 9 months ago (3 children)

I would separate NixOS from other immutable distros. NixOS is really about giving you blank slate and letting you fully configure it.

You do that configuration using a static config language that is able to be far more idempotent than Andible. It’s also able to define packages that are well contained and don’t require dynamic linking setup by manually installing other packages.

Immutable distros, on the other hand, really have no advantage to your setup and will probably feel more restrictive. The main use I see for them is for someone new or lazy that wants to get a working system up and running quickly.

[–] [email protected] 12 points 9 months ago (1 children)

My favorite example of how idempotent NixOS is has to do with the DE. If you've ever looked at switching from gnome to KDE, or the other way around, most distros suggest to just re-install because each DE leaves so much cruft around and it's so hard to remove everything in a safe manner.

With NixOS, you just change one line in your config, and the DE is cleanly swapped.

[–] [email protected] 6 points 9 months ago (1 children)

Or you can add specialisations, which to be fair might require a reboot (system accounts might change during specialisations switch which will confuse the script trying to reload services for the now non-existent user) but it is how I have multiple DEs installed without their applications flooding the other ones, each with their own login manager (SDDM for plasma, gdm for gnome, greetd for sway).

[–] [email protected] 1 points 9 months ago

Definitely. That's a great way to run different option together.

I was just using the DE as an example to demonstrate how cleanly NixOS can add and remove packages. The clean removal of packages with lots of configs is something that most distros struggle with.

[–] [email protected] 2 points 9 months ago* (last edited 9 months ago) (1 children)

Well maybe you youself are too new to recognize some of the appeals ;)

One large advantage with silverblue is, that the whole composition of the OS does not take place on the target machine. That means that all the issues that could arise will not take place on the target machine, and can be dealt with beforehand. In the simple case this could mean just enjoying vanilla silverblue without having to think about possibly borking the machine. In an advanced usecase this could mean for example building the os images in a GitLab CI/CD pipeline (with well working tooling that exists already for docker etc), then having automatic tests in the pipeline ensure that everything important works as expected. And only if the tests pass, the image will be added to the repositorie's image registry, where the target machines will fetch it from automatically and rebase to it.

[–] [email protected] 1 points 9 months ago (1 children)

No, I fully understand it. But if you build the whole system where every package is isolated, none of the packages interfere with each other, and every package is tested across a wide array of architectures, you can just as safely put together your ideal OS setup and don't have to deal with being locked into very simple and bare system.

The right place for immutable OSes is if you're using it as a server for container workloads, where you will never customize the base system. Or if you never want to customize your system. Yes, you can customize the system image, but it breaks all the guarantees that the images gives you because the packages themselves are not isolated and by bumping a wrong dependency for a custom packages you can still break the whole system.

[–] [email protected] 1 points 9 months ago (1 children)

Partly yes, but just installing a package without running into conflicts does not yet guarantee a working system. You have to cater for the right configurations too, for example when you think about a corporate setting with all kinds of networking whoes (like shares, vpns and such). I think you could get this to work with Nix somehow, but you want to test these things beforehand, and if you do so using images then you have the thing to ship to machines in your hands already, there's no need to compose the OS and configurations over and over again for every machine.

Another aspect with non-atomic OS composition on the target is that you have to deal with the transient phase from one state to the next. In this phase all kinds of things could happen, for example an update of nvidia drivers would render cuda disfunctional until the next reboot, as the userspace and kernelspace parts do not fit together anymore. With something like any of the fedora atomic variants, transient phases with basically undefined behaviour do not exist, and the time the system is not guaranteed to be in working order gets reduced to just the reboot.

Nix is cool and definetely better than any traditional package manager. But it is not an ultimate solution, to be honest so far it seems to me like it is living in a nieche of enthusiasts that are smart enough to put up with its unique declaration language. And below that niche you have ordinary linux users that may just be happy with silverblue without any modifications, and above that niche you have corporate doing their own images in CI/CD, CoreOS and all that jazz.

[–] [email protected] 1 points 9 months ago

Your summary of the language is spot on. I still hope that more distros take inspiration from the declarative config and try to move in the direction, or nix supports a better language in the future. I think that ultimately that's what the average linux user would want. The ability to still customize in a safe manner. Silverblue, and others, are and will remain a great option for the new or indifferent user.

On your point about the transient phase, nix actually does that by default already. It installs everything at a separate path and then flips over in one go. You can even pick the mode, either try to do a live switch as you describe, or on boot. I don't know if I see many benefits to images there.

I am at a second place now that uses NixOS in a corporate setting, and it is much easier than maintaining the CoreOS images, or similar. I've had some many broken builds of CoreOS images because something goes wrong between the custom packages and the base CoreOS images, I would rather just run an Ansible script at this point. Also, you end up using the exact same test suite for NixOS images as for your other images, so the same guarantees end up being met.

[–] wolf 1 points 9 months ago (1 children)

Thanks, that clarified things for me. Only thing I really would love to have are atomic updates, but for this I probably could just use BTRFS snapshots.

[–] [email protected] 2 points 9 months ago

Already has that. And if you use flakes, you can fully lock down your package versions that way the install is 100% identical on every machine no matter when you run it.

[–] [email protected] 20 points 9 months ago* (last edited 9 months ago)

Everyone here have already explained their various stances very eloquently and convincingly - so I won't argue against that - so instead I'll just put forth my own 2c on why I use Silverblue instead of Nix/Ansible.

The main draw for me in using Silverblue (well, uBlue to be exact) is the no-cost, cloud-based, industry-standard, CI/CD and OCI workflow. Working with these standard technologies also helps me polish up my skills for work, as we've started to make use of containers and gitops workflows, so the skills that I'm gaining at personal level are easily translatable for work (and vice-versa).

With Nix (the declarative way), I'd have to learn the Nix language first and maintain the non-standard Nix config files and, tbh, I don't want to waste so much time on something that no one in the industry actually uses. Declarative Nix won't really help me grow professionally, and whilst I agree it has some very unique advantages and use-cases, it's completely overkill for my personal needs. In saying that, I'm happy with using Nix the imperative way though - I don't need to learn the Nix language, and it's great having access to a vast package repository and access my programs without having to go thru the limitations of containers.

As for Ansible, I'd have to have my own server (and pay for it, if it's in the cloud), and spend time maintaining it too. And although we use Ansible at work as well, so the skills I gain here won't be waste of time, it's unfortunately too inflexible/rigid for my personal needs - my personal systems are constantly evolving, whether it is in the common packages I use, or my choice of DE (my most recent fling is with Wayfire) etc. With an Ansible workflow, I'd be constantly editing yaml files instead of actually making the change I want to see. It's overkill for me, and a waste of time (IMO). You could argue that I'm already editing my configs on Github with uBlue, but it's nowhere as onerous as having to write playbooks for every single thing. And as I mentioned, I like to maintain some flexibility and manual control over my personal machines and Ansible will just get in the way of that.

With the uBlue workflow, I just maintain my own fork on Github with most of my customisations, + a separate repository for specific dotfiles and scripts that I don't want to be part of my image. Pull bot keeps my main uBlue repo in sync with upstream, and I only need to jump in if there's some merge conflicts that cannot be resolved automatically. At the end of it all, I get a working OCI image, with a global CDN and 90 days of image archives, allowing for flexible rollback options - all of this without incurring any costs or wasting too much time on my part. Plus I can easily switch between different DEs and OCI distros, with just a simple rebase - I could go from a Steam-Deck like gaming experience (Bazzite) to a productivity-oriented workstation (Bluefin), or play around with some fancy new opinionated environments like Hyprland and River (Wayblue) - all with just a simple rebase and a reboot, without needing to learn some niche language or waste time writing config files. How cool is that?

[–] [email protected] 15 points 9 months ago

Ansible must examine the state of a system, detect that it is not in the desired state and then modify the current state to get it to the desired state. That is inheritently more complex than building a immutable system that is in the desired state by construction and can not get out of the desired state.

It's fine as ,one as you use other people's rules for ansible and just configure those, but it gets tricky fast when you start to write your own. Reliably discovering the state of a running system is surprisingly tricky.

[–] [email protected] 10 points 9 months ago* (last edited 9 months ago) (1 children)

Another aspect I like about Nix compared to what I understand from Ansible (which I used a bit but not much) is that your configuration describes your system without any hidden state. Yes, you only get your dependencies through full evaluation, but what I mean is this: Let's say you install something on a system, i.e. you add it to your list of packages, which you later remove. To my knowledge, Ansible won't remove the package if not explicitly asked. However, if you explicitly tell Ansible to not have it installed, what happens if that package is later introduced as a dependency?

Ansible will always operate on a stateful system, which is kind of the combination of what others have already mentioned – it's (EDIT: it being Nix) idempotent and there's no hidden state that will break something down the way.

[–] [email protected] 3 points 9 months ago

Ansible works on tasks, and to your hypothetical there, if you have a task that calls the package manager to put a package in the state 'absent', but it is another package's dependency, it will have little to do with ansible, and just follow the package manager's behaviour. (Up to some details. Like for 'apt', ansible runs the command with '-y', which has a little different behaviour than just removing the interaction part and assuming yes). If the package manager removes the depending package, and your playbook has first a task that installs it, then a taks that removes the dependency, you will always get 'changed' on both tasks everytime you run the playbook, even if your playbook puts the machine in the same state as before.

[–] [email protected] 8 points 9 months ago (2 children)

I use Fedora Silverblue and in my experience the updates are very stable. But with Debian and Ansible automation I think you are not missing a much, maybe nothing at all.

Would you mind sharing how you automated your setup with Ansible or generally how to use Ansible in that way? I use some bash scripts for my automation and it is a bit hacky, so if I could improve that, it would be nice.

[–] [email protected] 6 points 9 months ago

The thing about ansible is to always remember that it really is just a backup python script that gets copied to your server and executed. Yes it works quite well, but you have to be careful to not have break on you.

For me the difference to nix is, that my bud expression will actually always produce the same output or tell me it can't. Instead of ansible which will fail after some updates went past.

[–] wolf 3 points 9 months ago* (last edited 9 months ago) (2 children)

Yes, I really love the Silverblue download in the background, reboot and you are up to date updates. So much better than watching the package manager do its thing. :-)

I don't know about your knowledge about Ansible, and when you are already running Silverblue and are happy with it, it might be more worthwhile for you to explore how to automate Silverblue and the containers you are using... and write a blog post for people like me, how you did it, so I can learn. :-P

Ansible... basically it allows you to install software with the package managers (apt, dnf, ...), configure/restart etc. services, clone git repositories, run arbitrary commands, configure stuff with dconf.

Example for my workflow:

When Debian 12 got into the alpha stage, I simply set up a virtual machine, install git, ansible and vim, and then I start from a known starting place (like Gnome Desktop for desktops, minimal for servers). First, I clone my git repository with my dotfiles, and link all the relevant dotfiles. After that I simply use Ansible to install all packages I will use from that distribution, run dconf to configure Gnome for my needs, configure/download software from 3rd party package repositories or just download tarballs and install them to /opt or ~/opt. Of course also flatpaks can be configured/downloaded via Ansible.

Once, everything works great in the virtual machine I will work in the VM for a few days or even weeks. If everything works stable I'll just make a clean install of the operating system, add some hardware specific tweaks (change grub config, tweak WIFI drivers power mode) and then I am up and running. Thanks to Debian, my Ansible configs are mostly stable with minor tweaks for around 2 years, and when time is due for Debian 13, I'll repeat the cycle.

The way I do things with Ansible have grown for a long time and are tailored to my private/professional use cases. I simply like having the same setup on every desktop/server I deploy, because I never have to wonder, if my software is configured in the way I like it, if a hotkey works or if something I use is installed or not. (And if my hardware dies or I do an SSD upgrade, I am up and running within minutes, same is true if I get new hardware.)

Still, it is a tradeoff. I really like Fedora, but one year of updates is too short for me and my initial investment to setup a new version of Debian. Further, I only use dconf based desktops like Mate or Gnome, because I can simply configure them painless 100% via Ansible. OTOH I have MY Debian desktop setup running on multiple AMD64 and AARCH64 physical and virtual machines. If I want to experiment with software, I just create a VM, start Ansible, get a cup of tea and I have a disposable machine to play around. Further I have my setup 100% documented, if I wonder, what strange power settings tweak I needed in which file to make Debian 11 work on my netbook, I know were to find the 100% correct answer..

Excuse the wall of text, hope that gave you an idea, don't hesitate to reach out if any questions are left. Obviously, you have to decide for yourself if such a setup is worthwhile for you. In case you use only one Desktop, this would be total overkill. :-P

[–] [email protected] 2 points 9 months ago (1 children)

Thank you for this in depth answer. It makes me want to explore Ansible and setup automation. Sounds really great!

and write a blog post for people like me, how you did it, so I can learn.

I am thinking about that ... 🤔

[–] wolf 1 points 9 months ago

Really, Ansible doesn't matter, the IaC part is the killer.

Just start to put your config into code and learn, over time it will grow!

I cannot go back to setting desktops/servers up by hand, IaC just solves too many problems and gives me peace of mind.

[–] [email protected] 2 points 9 months ago (1 children)

Reading this, I find myself really, REALLY wanting to replicate that sort of setup, especially the docs part which is something I've been neglecting. I always say to myself, "The next Arch install, I'll document the setup" and it never happens!

[–] wolf 1 points 9 months ago (1 children)

“The next Arch install, I’ll document the setup” - Famous last words! :-)

Seriously, I wonder how good my approach would work with a rolling distribution like Arch. I would be afraid, that pacman updates would drift/change the system and over time the delta to my assumed setup grows... OTOH if you keep your scripts in sync with Archs updates, you might simply distribute the maintenance of your Ansible script. If you go full Ansible with Arch, please give an experience report in 6 months!

[–] [email protected] 2 points 9 months ago

I don't think I will. I switch between Arch and NixOS constantly, and this time (I'm on NixOS right now) I intend on remembering distrobox is a thing if I need to compile from source.

[–] [email protected] 8 points 9 months ago

Silverblue doesn't solve the same problems as Nix, or Ansible for that matter. I built my own in the past and it was non-trivial - although the CI process could pair quite nicely with Ansible. IMHO the primary advantage of Silverblue is that updates are a download, with practically zero work to do after the download has completed (this is a very big deal for RPM-based systems because an update boot can take a long time).

As for Ansible vs Nix, try switching from one program to another across all your machines. It's doable but not fun. Now try switching back across all your machines. Nix makes your system equal a configuration, it does not add configuration.

[–] [email protected] 4 points 9 months ago* (last edited 9 months ago)

I switched from a big custom Ansible deployment to NixOS.

The system includes 8 managed machines, multiple VPNs and a custom certificate authority.

Downsides:

rethinking of how to manage Certificates and VPN configs outside of Nix
getting secrets to work took a bit until I found agenix
deployments can take a while with deploy-rs

Still, I can only tell you how much more at ease I feel with the NixOS based system. Its just much easier to refactor, not having to take care of legacy cleanup and polluting the machines over time.

Once you wrap your head around it all more complex system architectures start to become manageable/maintainable.

IaC

You still need sth like Terraform on the side for your actual infrastructure provisioning.

Solutions to bridge this with the Nix ecosystem are evolving in the nix-community repos on Github, but I found it easier to manage that separately for the time being.

All in all I would recommend NixOS based systems for the heavy lifters in your setup. If you want to deploy a fleet of machines you are entering new territory. Exciting, but maybe too much of a time commitment for some.

[–] [email protected] 3 points 9 months ago (1 children)

OP, can you link to your desktop configuration using Ansible? How do you use it?

[–] wolf 3 points 9 months ago (1 children)

Sorry, I have only Ansible files at work which I cannot share and my private Ansible setup is in a private git repository. I elaborated further down in another comment my workflow.

My suggestion is to forget about best practices (like roles) for private desktop setup, simply start with a task file and a fresh installation of your favorite distro inside a virtual machine. From that starting point, everything you do to configure the VM you do via Ansible. Want to set the hostname? Learn about ansible.builtin.hostname, want do install a package? Use ansible.builtin.apt, ansible.builtin.dnf or similar, want to harden your sshd config? Look at ansible.builtin.lineinfile, ansible.builtin.copy or ansible.builtin.template ... Screwed up your VM? Replace it with a new one, run your Ansible tasks and continue were you left off...

Hope that helps!

[–] [email protected] 3 points 9 months ago (1 children)

Thanks. I use Ansible myself, but I was more interested in how I would run Ansible on my daily driver, from my daily driver.

[–] wolf 1 points 9 months ago

Sorry, perhaps I do not understand what you are asking for?

On a *NIX box you install ansible, start sshd and then run something like:

ansible-playbook -i inventory -u username -e 'ansible_user=username' all.yml  -K --limit hostname.domain.net

[–] [email protected] 1 points 9 months ago (1 children)

I think you have arguments about MicroOS (or Silberblue, which I know less about, and possibly Nix, which I know nothing about, and it seems to me it is not in the same group) wrong. Take a look at this https://youtu.be/lKYLF1tA4Ik.

load more comments (1 replies)

[–] [email protected] 1 points 9 months ago

I appreciate this is more asking about nicks, but I’ll offer some feedback on my experience with immutable distributions more generally.

I took an adventure into silver blue and micro OS recently and I was completely unimpressed. It’s a novel idea from a good place, but it was the most incoherent and buggy experience I’ve ever had on Linux distribution in the past 10 years. Nothing walked reliably, and everything broke, I also found that trying to use anything other than the default gnome desktop was an exercise in futility.

I need to clarify, I think it’s a great idea. In practice though, Both implementations, silver blue and micro OS, are really over engineered.

I have adapted the ideas into my current install and I achieve the same thing with A/B Snapshots And a script that takes me from a base snapshot to my daily driver. Everything else exists in containers So bootstrapping up only involves half a dozen packages (iwd, node, nvim etc. ).

load more comments