8 ms·

Can you do NixOS without systemd? If not, I'd look elsewhere for the distro. Maybe Guix?

by b9be520d93286 5y ago

jeppesen-io 5y ago
Just take the time to learn systemd. Once you do, like nix, it saves so much time
- gigatexal 5y ago
  Yeah no point in fighting it. It’s the standard. Learn to love SystemD.
- rollcat 5y ago
  systemd is so complex, I've come to a conclusion, that it no longer fits my definition of free software. We allow runaway complexity to obscure the inner workings of an important software package, to the point, where having source access no longer makes a practical difference to a "casual" power-user or even a software engineer. I can source-dive runit, s6, OpenBSD's rc, or OpenRC and within a weekend, have a pretty OK understanding, fix a bug, or add a feature. Having software as complex as systemd taking so many roles, and making itself so ubiquitous and irreplaceable, makes me feel that I no longer have any control or understanding of my system, bugs or misfeatures just become things you live with, or you riddle yourself with arcane workarounds. Portability suffers, monoculture takes root. I've lost faith in "mainstream" Linux distros. I use macOS and OpenBSD for workstations, and Alpine where I need e.g. Docker. It must either be simple enough to understand, or provide enough utility/convenience that the lack of (practical) source access is compensated. systemd fits neither category.
  - candiddevmike 5y ago
    Yes, systemd has a ton of surface area and options. Yes, the man pages are long. No, you don't need to read them--the beauty of systemd is you control how much of the complexity you use. Unit files can be 10 lines or 30. Most of the extra options are for security and hardening, when you need them you'll be glad they're easy to turn on. For the other components, I think have a stable, familiar, and consistent set of core services (boot, ntp, logging, networking) is glorious
  - viraptor 5y ago
    Have you actually tried to dive into the part you're interested in? Where did you find the complexity? I've done it a few times for different components and found them pretty well separated and the source pretty straightforward. I have other issues with them, but complexity/obscurity of the is was not one of them.
    - Aeolun 5y ago
      Looking at using systemd to just run a binary automatically on boot (which some smart person on HN told me was the easiest way). Just looking at the systemd landing page overwhelms me. Boot Loader Interface, Discoverable Partitions Specification, etc. I’m sure the implementation details are very interesting. But where is the “Configure and Start a Service” option? Which is arguably the most important.
      - md8z 5y ago
        The man pages are the reference manual. You might want to search for "systemd service tutorial" or something like that, there's a lot of blogs that explain how to make a simple service.
      - viraptor 5y ago
        Their frontpage sucks, but that's not related to the code really :) For a quick intro to new services, see the examples here: https://www.freedesktop.org/software/systemd/man/systemd.service.html#Examples https://www.freedesktop.org/software/systemd/man/systemd.ser... (they should cover most basic needs) then read above for the details on the parameters. You stick the file in /etc/systemd/system/your_thing.service and enable/start it.
      - markstos 5y ago
        I'm not sure why this comment was downvoted. I've read all the systemd documentation and this comment is spot on. System is lacking good documentation along the lines of "the least you need to know to setup and manage a service". No, it's not as easy as "man systemd.service". What's probably most useful in that documentation is the "hello world" example, which is buried at the bottom of the documentation. Also, key details are elsewhere, in "man systemd.exec" and "man systemd.unit". The systemd docs a great comprehensive reference, but the man pages are poor introductory documentation. Some useful tips that are hard to find: * man systemd.directives documents every directory and will tell you which man page as the full documentation for it. * man systemd.index lists every man page related to systemd.
  - ben0x539 5y ago
    That's an interesting line to draw! Do you think this also extends to stuff like firefox or java vm, or are you only focusing on "system" software with that analysis?
    - rollcat 5y ago
      I'm trying to balance between idealism and pragmatism. Source access is pragmatic only in a situation where you feel confident to dive it. I admire projects like suckless, Alpine, or Netsurf, because they prove this kind of balance can be maintained. But I'm still posting this from Safari ;)
    - josephcsible 5y ago
      The key is how necessary the complexity is. The existence of simpler alternatives to systemd (that work just as well to run a system with) prove that its complexity is unnecessary. For things like Web browsers, the complexity is necessary, for better or worse.
- drran 5y ago
  Good parts of SystemD are good, bad parts are bad. SystemD is easy to use when it fits your needs, but pain to use otherwise. For example, `systemd-analyze` is a good tool for boot performance analysis, so + for systemd, but if I want/need to use perf for boot performance analysis, then systemd stands in my way, while for initd it's just yet another boot mode.
  - md8z 5y ago
    What's the limitation stopping you from using perf in the same way as you would before? I've never had the need to try to do that.
- josephcsible 5y ago
  Responding to "I don't like this" with "just learn it" is effectively saying "anyone who disagrees with me that this thing is awesome only does so because they know less than me." I'm very familiar with systemd, and I make use of its features on systems I can't avoid it on, but I still hate it.
- daptaq 5y ago
  Can you recommend any links or literature to learn more about systemd, beyond the basics?
xyzzyz 5y ago
What would you prefer to have in Nix instead of systemd?
- b9be520d93286 5y ago
  I would prefer OpenRC, runit or something similar.
  - md8z 5y ago
    Those would probably be not so great matches for NixOS because they don't support the container stuff that systemd does, you would be throwing all that out.
    - NewJazz 5y ago
      Some people don't care. Some people want their boot ordering software and container runtime software to live in different code bases.
      - md8z 5y ago
        With cgroupsv2 there seems to be very little benefit to doing that since the container runtime needs to sit at the top of the process tree anyway, so I'm not sure I understand what the purpose of that would be or why you would want that. If you were using containers to run services then I can't really think of a situation where you wouldn't also want it as part of the boot ordering process, so your services will just have it working immediately upon boot.
        NewJazz 5y ago
        That is not true at all about cgroup2. Also think outside the box. Not everyone is using cgroups and namespaces. Some people are out there using gvisor, or KVM, or FreeBSD jails.
        5y ago
mindslight 5y ago
NixOS is based on systemd. But it also seems like NixOS would be a great foundation to use something besides systemd. It would take some work of course, but it feels like you'd be mostly working with the OS rather than fighting it. However having used it, NixOS seems like it mitigates the worst aspects of systemd. It gets rid of that that /etc/systemd /lib/systemd symlink "cleverness" for overriding/enabling units. Being functional makes it so that when systemd mysteriously breaks - for example if there is a loop in dependencies - it's easy to track down the change that caused it. And rather than splaying the config out in a bunch of random "unit" files, it's all contained in the nix config. About the worst thing I can say is that defining your own service is a bit more obtuse that it needs to be, with the arbitrary terms of the systemd unit format carrying over into the Nix config.
- md8z 5y ago
  The symlinking is one of the things systemd actually gets right on traditional distros. The files in /usr/lib are immutable data files shipped by the packages that you're not supposed to edit. The symlinks to them in /etc are configuration that you can change.
  - mindslight 5y ago
    I get the rationale. it just makes for one more layer of indirection that you have to overcome when trying to figure out what the configuration actually looks like.
    - md8z 5y ago
      Well I think you are supposed to just use systemctl to see what the configuration looks like.
    - 5e92cb50239222b 5y ago
      Why would you do this manually? You also have to remember to check multiple configuration paths (e.g. override units), all of which can have an additional `.d` include directory. This is the price you pay for the flexibility systemd provides (and I argue it's much better than random System V-style shell scripts that can include anything at all, maybe even some remote scripts piped from curl to sh if developers was mad enough). Just use `systemctl cat`, it prints the whole effective configuration.
steve-chavez 5y ago
Not yet AFAICT. I've been following the nix-processmgmt[1] project, which looks it could make NixOS independent of the init system. [1]: https://github.com/svanderburg/nix-processmgmt https://github.com/svanderburg/nix-processmgmt
- mrobot 5y ago
  This is great, thank you. I was gonna start on something like this myself, glad i did not duplicate effort with it yet.
Ericson2314 5y ago
I haven't bothered to have a beef with systemd, but some of us have discussed https://github.com/InitWare/InitWare https://github.com/InitWare/InitWare to support non-Linux kernels. That would be really fun.
ayushnix 5y ago
I doubt GuixSD would work on most modern hardware considering it uses the Linux-libre kernel. Using the Guix package manager itself sounds useful though.
- rekado 5y ago
  Guix System works fine on modern hardware. I've been using it on new servers for the build farm at ci.guix.gnu.org and on laptops. Linux-libre has not been a problem. The biggest recurring issue is with graphic cards that have poor support in Linux and require firmware blobs and with WiFi cards that have no free drivers / firmware. It is trivial to use vanilla Linux with these machines as Guix System lets you use any other package for the `kernel` field in the configuration. The "nonguix" channel (hosted on Github) provides packages for vanilla Linux ("linux") in various versions, and also includes firmware packages that you can use in your config file. If that's the only thing keeping you from using Guix System then I'm happy to say that it's a hurdle that is very easy to overcome.
  - ayushnix 5y ago
    > The biggest recurring issue is with graphic cards that have poor support in Linux and require firmware blobs and with WiFi cards that have no free drivers / firmware. Intel, AMD, and Nvidia GPUS - all of them need firmware blobs to work as expected. Intel and AMD offer free drivers but not free firmware. And if you want to WiFi 5 (ac) or WiFi 6 (ax), chances are that you'll need non-free drivers/firmware as well. > The "nonguix" channel (hosted on Github) provides packages for vanilla Linux ("linux") in various versions, and also includes firmware packages that you can use in your config file. Ah, that's good to know. I'll probably give the Guix package manager a shot some day.

Can you do NixOS without systemd? If not, I'd look elsewhere for the distro. Maybe Guix?

jeppesen-io 5y ago

Just take the time to learn systemd. Once you do, like nix, it saves so much time

gigatexal 5y ago
Yeah no point in fighting it. It’s the standard. Learn to love SystemD.
rollcat 5y ago
systemd is so complex, I've come to a conclusion, that it no longer fits my definition of free software. We allow runaway complexity to obscure the inner workings of an important software package, to the point, where having source access no longer makes a practical difference to a "casual" power-user or even a software engineer. I can source-dive runit, s6, OpenBSD's rc, or OpenRC and within a weekend, have a pretty OK understanding, fix a bug, or add a feature. Having software as complex as systemd taking so many roles, and making itself so ubiquitous and irreplaceable, makes me feel that I no longer have any control or understanding of my system, bugs or misfeatures just become things you live with, or you riddle yourself with arcane workarounds. Portability suffers, monoculture takes root. I've lost faith in "mainstream" Linux distros. I use macOS and OpenBSD for workstations, and Alpine where I need e.g. Docker. It must either be simple enough to understand, or provide enough utility/convenience that the lack of (practical) source access is compensated. systemd fits neither category.
- candiddevmike 5y ago
  Yes, systemd has a ton of surface area and options. Yes, the man pages are long. No, you don't need to read them--the beauty of systemd is you control how much of the complexity you use. Unit files can be 10 lines or 30. Most of the extra options are for security and hardening, when you need them you'll be glad they're easy to turn on. For the other components, I think have a stable, familiar, and consistent set of core services (boot, ntp, logging, networking) is glorious
- viraptor 5y ago
  Have you actually tried to dive into the part you're interested in? Where did you find the complexity? I've done it a few times for different components and found them pretty well separated and the source pretty straightforward. I have other issues with them, but complexity/obscurity of the is was not one of them.
  - Aeolun 5y ago
    Looking at using systemd to just run a binary automatically on boot (which some smart person on HN told me was the easiest way). Just looking at the systemd landing page overwhelms me. Boot Loader Interface, Discoverable Partitions Specification, etc. I’m sure the implementation details are very interesting. But where is the “Configure and Start a Service” option? Which is arguably the most important.
    - md8z 5y ago
      The man pages are the reference manual. You might want to search for "systemd service tutorial" or something like that, there's a lot of blogs that explain how to make a simple service.
    - viraptor 5y ago
      Their frontpage sucks, but that's not related to the code really :) For a quick intro to new services, see the examples here: https://www.freedesktop.org/software/systemd/man/systemd.service.html#Examples https://www.freedesktop.org/software/systemd/man/systemd.ser... (they should cover most basic needs) then read above for the details on the parameters. You stick the file in /etc/systemd/system/your_thing.service and enable/start it.
    - markstos 5y ago
      I'm not sure why this comment was downvoted. I've read all the systemd documentation and this comment is spot on. System is lacking good documentation along the lines of "the least you need to know to setup and manage a service". No, it's not as easy as "man systemd.service". What's probably most useful in that documentation is the "hello world" example, which is buried at the bottom of the documentation. Also, key details are elsewhere, in "man systemd.exec" and "man systemd.unit". The systemd docs a great comprehensive reference, but the man pages are poor introductory documentation. Some useful tips that are hard to find: * man systemd.directives documents every directory and will tell you which man page as the full documentation for it. * man systemd.index lists every man page related to systemd.
- ben0x539 5y ago
  That's an interesting line to draw! Do you think this also extends to stuff like firefox or java vm, or are you only focusing on "system" software with that analysis?
  - rollcat 5y ago
    I'm trying to balance between idealism and pragmatism. Source access is pragmatic only in a situation where you feel confident to dive it. I admire projects like suckless, Alpine, or Netsurf, because they prove this kind of balance can be maintained. But I'm still posting this from Safari ;)
  - josephcsible 5y ago
    The key is how necessary the complexity is. The existence of simpler alternatives to systemd (that work just as well to run a system with) prove that its complexity is unnecessary. For things like Web browsers, the complexity is necessary, for better or worse.
drran 5y ago
Good parts of SystemD are good, bad parts are bad. SystemD is easy to use when it fits your needs, but pain to use otherwise. For example, `systemd-analyze` is a good tool for boot performance analysis, so + for systemd, but if I want/need to use perf for boot performance analysis, then systemd stands in my way, while for initd it's just yet another boot mode.
- md8z 5y ago
  What's the limitation stopping you from using perf in the same way as you would before? I've never had the need to try to do that.
josephcsible 5y ago
Responding to "I don't like this" with "just learn it" is effectively saying "anyone who disagrees with me that this thing is awesome only does so because they know less than me." I'm very familiar with systemd, and I make use of its features on systems I can't avoid it on, but I still hate it.
daptaq 5y ago
Can you recommend any links or literature to learn more about systemd, beyond the basics?

xyzzyz 5y ago

What would you prefer to have in Nix instead of systemd?

b9be520d93286 5y ago
I would prefer OpenRC, runit or something similar.
- md8z 5y ago
  Those would probably be not so great matches for NixOS because they don't support the container stuff that systemd does, you would be throwing all that out.
  - NewJazz 5y ago
    Some people don't care. Some people want their boot ordering software and container runtime software to live in different code bases.
    - md8z 5y ago
      With cgroupsv2 there seems to be very little benefit to doing that since the container runtime needs to sit at the top of the process tree anyway, so I'm not sure I understand what the purpose of that would be or why you would want that. If you were using containers to run services then I can't really think of a situation where you wouldn't also want it as part of the boot ordering process, so your services will just have it working immediately upon boot.
      - NewJazz 5y ago
        That is not true at all about cgroup2. Also think outside the box. Not everyone is using cgroups and namespaces. Some people are out there using gvisor, or KVM, or FreeBSD jails.
        5y ago

mindslight 5y ago

NixOS is based on systemd. But it also seems like NixOS would be a great foundation to use something besides systemd. It would take some work of course, but it feels like you'd be mostly working with the OS rather than fighting it. However having used it, NixOS seems like it mitigates the worst aspects of systemd. It gets rid of that that /etc/systemd /lib/systemd symlink "cleverness" for overriding/enabling units. Being functional makes it so that when systemd mysteriously breaks - for example if there is a loop in dependencies - it's easy to track down the change that caused it. And rather than splaying the config out in a bunch of random "unit" files, it's all contained in the nix config. About the worst thing I can say is that defining your own service is a bit more obtuse that it needs to be, with the arbitrary terms of the systemd unit format carrying over into the Nix config.

md8z 5y ago
The symlinking is one of the things systemd actually gets right on traditional distros. The files in /usr/lib are immutable data files shipped by the packages that you're not supposed to edit. The symlinks to them in /etc are configuration that you can change.
- mindslight 5y ago
  I get the rationale. it just makes for one more layer of indirection that you have to overcome when trying to figure out what the configuration actually looks like.
  - md8z 5y ago
    Well I think you are supposed to just use systemctl to see what the configuration looks like.
  - 5e92cb50239222b 5y ago
    Why would you do this manually? You also have to remember to check multiple configuration paths (e.g. override units), all of which can have an additional `.d` include directory. This is the price you pay for the flexibility systemd provides (and I argue it's much better than random System V-style shell scripts that can include anything at all, maybe even some remote scripts piped from curl to sh if developers was mad enough). Just use `systemctl cat`, it prints the whole effective configuration.

steve-chavez 5y ago

Not yet AFAICT. I've been following the nix-processmgmt[1] project, which looks it could make NixOS independent of the init system. [1]: https://github.com/svanderburg/nix-processmgmt https://github.com/svanderburg/nix-processmgmt

mrobot 5y ago
This is great, thank you. I was gonna start on something like this myself, glad i did not duplicate effort with it yet.

Ericson2314 5y ago

I haven't bothered to have a beef with systemd, but some of us have discussed https://github.com/InitWare/InitWare https://github.com/InitWare/InitWare to support non-Linux kernels. That would be really fun.

ayushnix 5y ago

I doubt GuixSD would work on most modern hardware considering it uses the Linux-libre kernel. Using the Guix package manager itself sounds useful though.

rekado 5y ago
Guix System works fine on modern hardware. I've been using it on new servers for the build farm at ci.guix.gnu.org and on laptops. Linux-libre has not been a problem. The biggest recurring issue is with graphic cards that have poor support in Linux and require firmware blobs and with WiFi cards that have no free drivers / firmware. It is trivial to use vanilla Linux with these machines as Guix System lets you use any other package for the `kernel` field in the configuration. The "nonguix" channel (hosted on Github) provides packages for vanilla Linux ("linux") in various versions, and also includes firmware packages that you can use in your config file. If that's the only thing keeping you from using Guix System then I'm happy to say that it's a hurdle that is very easy to overcome.
- ayushnix 5y ago
  > The biggest recurring issue is with graphic cards that have poor support in Linux and require firmware blobs and with WiFi cards that have no free drivers / firmware. Intel, AMD, and Nvidia GPUS - all of them need firmware blobs to work as expected. Intel and AMD offer free drivers but not free firmware. And if you want to WiFi 5 (ac) or WiFi 6 (ax), chances are that you'll need non-free drivers/firmware as well. > The "nonguix" channel (hosted on Github) provides packages for vanilla Linux ("linux") in various versions, and also includes firmware packages that you can use in your config file. Ah, that's good to know. I'll probably give the Guix package manager a shot some day.