From 3f653f4bc8e6a0da358665a83662b591a5ddf288 Mon Sep 17 00:00:00 2001 From: Matej Focko Date: Mon, 5 Feb 2024 00:33:11 +0100 Subject: [PATCH] blog(lts-distros): add the finished post Closes #14 Signed-off-by: Matej Focko --- blog/2024-02-07-lts-distros.md | 480 +++++++++++++++++++++++++++++++++ 1 file changed, 480 insertions(+) create mode 100644 blog/2024-02-07-lts-distros.md diff --git a/blog/2024-02-07-lts-distros.md b/blog/2024-02-07-lts-distros.md new file mode 100644 index 0000000..ef97a20 --- /dev/null +++ b/blog/2024-02-07-lts-distros.md @@ -0,0 +1,480 @@ +--- +title: LTS distributions +description: | + Shower thoughts on the LTS Linux distributions. +date: 2024-02-07 +authors: + - key: mf + title: a.k.a. small Fedora maintainer +tags: + - lts + - linux distributions + - support + - paywall +hide_table_of_contents: false +--- + +Linux distributions are a common choice for running the servers. There's a wide +variety of distributions, but on the servers majority is made by only a few. + +Some corporations also profit from the support of the “big” distributions. Let's +dive into the pros, cons and peculiarities of such _business_. + +This post is inspired/triggered by the following Mastodon post: +[![Mastodon post about Ubuntu Pro](https://cdn.pawb.social/mastodon-fe/media_attachments/files/111/864/549/106/543/961/original/f4dac207fb93ffa8.png)](https://hackers.town/@antijingoist/111864760073049505) + + + +:::caution Disclaimer + +You may take my opinion with a grain of salt, since I'm affiliated with Red Hat, +but at the same time I've also seen the other side of the fence, so I know how +it works from the perspective of the provider/maintainer. + +::: + +:::tip + +If you are not very oriented in the matters of Linux distributions and +maintaining of packages, I suggest looking at the [glossary](#glossary) at the +end to have a better grasp of the terms that are used throughout the post. + +::: + +## Point of linux distributions + +First thing I'd like to point out is the point of the Linux distributions. What +benefit do they provide? And why there are so many of them… + +As it has been brought up many times by the _rms_[^1], Linux by itself is not +enough, it's just the kernel that does the underlying work. We need more +software to utilize the hardware. That's the gap that Linux distributions bridge +by providing the Linux and much more other software that we need. + +Each distribution is unique in its own way. Some prefer different ways of +handling the software (like Gentoo that allows you to compile it yourself) and +others stable releases of software (like Debian). + +In the end it mostly boils down to the packaging. I, as a user, want to do +something like + +``` +$ sudo dnf5 install firefox +``` + +and not bother about anything else. I don't want to open browser to look the +thing up, download it and then click mindlessly 500× “Next”. I just want to run +one command and when the maintainers decide it's time to move on, another one to +upgrade the software to the newer version. + +Of course, for some use cases you want to minimize the latter. And even make +sure that it's safe to do it when you need to. You don't want to break your +production deployment just because someone decided it's time to push something +out. + +That's when the _maintainers_ come in. They take upon themselves the +responsibility of maintaining the packages. If you've ever used the Debian, you +know very well how _old_ the software is, but that's what you might need for +your servers. + +## Pain of packaging + +Packaging software _is not_ cost-free. You may as well have 80 % of packages +that don't need much care and it's rather easy to push them forward, but those +remaining, which are complicated and raise issues regularly, will make it up and +take a lot of time and also pain. + +Libraries are the most common example that might not need much work to be done. +On the other hand, Linux kernel itself is a rather complicated machinery that +is patched **a lot** and its build process is not simple either. + +Even if you consider just those _easily-maintainble_ packages, the process can +be tedious, boring and overall time consuming. + +:::tip Shameless RHEL-based ecosystem plug + +[Packit] can help tremendously with the _easily-maintainable_ packages, since it +**can** be automated. + +::: + +### Packaging whole ecosystems + +Now it's time to talk about whole ecosystems that have some kind of a packaging +by themselves. Yes, I mean Python (with its continuous stream of different +package managers), Rust, Go, etc. + +Whole point of packaging is to have some form of _gating_. In other words, you +want some kind of _quality control_ when pushing changes into the Linux distros. + +If you want to package some tool (or even library) from the aforementioned +ecosystems, you need to package all of the dependencies to make sure something +doesn't get updated in the meantime (and also that you can safely reproduce the +builds, if need be). + +I've tried to package some utilities for EPEL both in Rust and Go. Dependencies +form a DAG[^2] and in case of Rust, it's _very_ similar to the way `npm` does +its packaging. + +:::danger Spoiler alert + +You get a lot of dependencies. And since it's a tree of dependencies, there may +be **a lot** of them. + +::: + +I have no clue how do the Rust maintainers operate, but I'm tipping my fedora in +their direction, since it must be a _pain in the ass_. + +## Paid distributions + +You can find few Linux distributions that are “paid”. I'm very well aware of the +fact I've used quotes around the word, cause it's not that easy and not even +same for all of the distributions that involve some kind of a payment. + +One of the first non-free distributions I've come into contact was _[Zorin OS]_ +which basically tries to be the best _transition_ solution when moving away from +the Windows or macOS. If you have a look at the _perks_ of its _Pro_ version +that's paid, you may as well decide they are rather questionable… + +It's time to move into the _Ubuntu Pro_, _RHEL_ and _SLE_ territory. What's the +point of those? They definitely offer different kind of, let's say, +_non-free experience_. + +With those you are paying mainly for the support and bug/security patches. + +:::tip Fun fact + +There's no mention of any kind of support on the Zorin page… Apart from the fact +that _you are supporting_ the Zorin development. + +::: + +## Repository structure + +As I have mentioned above, the three _services_[^3] I mentioned are providing +support with regards to bugs and security vulnerabilites. Therefore it makes +sense to have some kind of a process in place when you're pushing changes +(either updates, patches or _security_ patches) to the distribution. And yes, +these processes are _in place_. + +If you think about the amount of packages that is present in the community +distributions like _archLinux_ (14,830 packages) or _Fedora_ (74,309 packages), +it is safe to come to a conclusion that _there's no way_ to support all of them. + +:::tip archLinux + +It may seem that archLinux contains rather small set of packages, but one of the +_killer features_ of archLinux lies in the AUR (archLinux User Repository) where +you can find additional **93,283** packages. + +::: + +That's why the Linux distributions have some structure to their repositories +that contain packages. The way you go around this is rather simple, you choose +some set of _critical_ packages that you guarantee support for (like Linux +kernel, openSSL, etc.) and maintain those with all the QA processes in place. + +:::caution Unpopular opinion + +This is also one of the reasons why I'm quite against packaging anything and +everything into the Linux distribution. In my opinion it is impossible to +**properly** maintain **huge** set of packages and enforce some kind of +**quality control**. + +::: + +### Ubuntu + +Ubuntu has pretty granular structure of their repositories, namely: + +- `main` containing the “core” of the Ubuntu that is maintained by the Canonical, +- `universe` containing literally the “universe”, packages that everyone likes, + but they're not crucial, this repo is maintained mostly by the community, +- `multiverse` containing packages with some license or copyright issues, and +- `restricted` containing _proprietary_ packages like nvidia drivers and such. + +By briefly checking my Ubuntu 23.10 installation, here are stats of packages in +their respective repositories: + +- `main` with 6,128 packages, +- `universe` with 63,380 packages, +- `multiverse` with 997 packages, and finally +- `restricted` with 784 packages. + +As you can see, if we sum them up, they are relatively similar to the Fedora +numbers. + +### CentOS + +CentOS on the other hand has a bit simpler structure with BaseOS for the base +and AppStream for additional packages: + +- `baseos` with 1,058 packages, +- `appstream` with 5,646 packages, and +- `extras-common` with 42 packages. + +Overall they make up the similar number as the Ubuntu's `main` repository. And +you can also notice that there are no additional repositories. + +:::tip + +There's also a CRB (CodeReady Builder) repository with dev packages like headers +and such. + +And you can also enable EPEL (Extra Packages for Enterprise Linux) which is +community-supported and provides another 19,903 packages. + +::: + +## Ubuntu Pro + +Now it's time to get back to the Ubuntu Pro. There are multiple points that need +to be taken in account to be either positive or negative about it… + +We can start with the way Ubuntu is released and maintained. Ubuntu has regular +6-month release cycle and biannual LTS release. Releases are normally supported +for 9 months with the exception of the LTS releases being supported for 5 years. + +If you check out the _[Ubuntu Pro]_ website, you can find the following +statement: + +> **Ubuntu Pro** +> +> The most comprehensive subscription for open-source software security +> +> 30-day trial for enterprises. Always free for personal use. + +:::tip Personal use + +Ubuntu Pro for _personal use_ consists of 5 installations and in case of the +community _ambassadors_ 50. + +::: + +Overall if you try to find what is included in the Ubuntu Pro: + +- high and critical patches, +- 10 years of maintenance, and +- (optional) 24/7 enterprise-grade support. + +If we get back to the screenshot all the way at the beginning of the post: +[![Mastodon post about Ubuntu Pro](https://cdn.pawb.social/mastodon-fe/media_attachments/files/111/864/549/106/543/961/original/f4dac207fb93ffa8.png)](https://hackers.town/@antijingoist/111864760073049505) + +and try to look up to which repository the packages mentioned in the screenshot +belong, we will find out that they belong to `universe` repository which is +maintained by the community. Not to mention nature of the packages: multimedia. + +You may think about this as a scam, but considering repository consisting of 70k +packages, it is not an easy task to do. And with LTS releases we're talking +about 5+ years of support. + +:::info Fedora + +Try to compare this state to Fedora. It also has a 6-month release cycle, but +there are no LTS releases and each release is supported only for a year. + +::: + +Common strategy, at this point, is to pull out the _open-source_. Yes, we are +still dealing with the open-source, but keep in mind that you're trying to patch +some issue in a version that's 5 years old, upstream definitely doesn't care +anymore[^4], the development didn't stop 5 years ago, it's going on and fixing +this issue in a release from 5 years is not the same as fixing it in the current +release. At this point, if you are paying for such support, you are actually +paying for someone to do _software archaeology_ which **can be** _non-trivial_ +to do. + +In the case of Ubuntu Pro we're talking about community support and best-effort +support by Canonical for the paying customers. And that makes sense to me, +running LTS distro for 5+ years on a desktop seems like an odd choice, even +with the help of _[podman]_ and _[distrobox]_ or _[toolbx]_ that allow us to use +stable or LTS distro as a base and containerized development environments on top +of that. + +## RHEL ecosystem + +RHEL ecosystem is much more complicated in this matter. However it's very +similar to the way SUSE operates with few exceptions. + +You can see a flow diagram here: + +```mermaid +flowchart LR; + U[upstream] --> FR[Fedora Rawhide]; + FR --> F[Fedora release]; + F --> C[CentOS Stream]; + C --> R[RHEL]; +``` + +Key things to take and not to take from the flow diagram: + +- getting from one upstream to its respective downstream is not as simple as the + presence of an arrow and it's not the same process for all of them +- lengths of the arrows are not proportional, specifically: + - Fedora Rawhide is _supposed to_ consume updates as soon as possible, + - depending on the decision of the maintainer they can, but _don't have to_ be + included in the currently supported Fedora releases (you can take [Emacs] as + an example of such package), but Rawhide eventually becomes the next Fedora + release, + - CentOS Stream gets branched off a specific Fedora release, and then + - ultimately CentOS Stream becomes the next **minor** release of RHEL. +- this diagram is simplified by **a lot** + +:::tip SUSE flow for comparison + +I'll also include a SUSE flow, so you can compare: + +```mermaid +flowchart LR; + U[upstream] --> T[openSUSE Tumbleweed]; + T --> L[openSUSE Leap]; + L --> S[SUSE Linux Enterprise]; + S --> L; +``` + +You can notice, as opposed to the RHEL ecosystem, some changes are being +backported to the openSUSE Leap. + +However this is subject to change as there is a new [ALP] project arising which +is, more than likely, going to replace the Leap. + +::: + +### Change in the model + +The flow I've shown above is in effect since late ‘20 and early ‘21. I hope you +can see that it is quite similar to the way SUSE operates too. Before late ‘20 +the flow was following: + +```mermaid +flowchart LR; + U[upstream] --> FR[Fedora Rawhide]; + FR --> F[Fedora release]; + F --> R[RHEL]; + R --- C[CentOS]; +``` + +CentOS was the last distribution in that “chain”. This provides some benefits +and some negatives. + +#### Before the change + +From the point of a developer, unless you have some kind of an early access to +RHEL, you don't see the changes until they land and are already released. This +impairs your ability to test and verify your software before shipping it to your +clients that use RHEL. + +From the point of a user, there is one positive, you basically get “free RHEL” +without the support. This also allowed you to report bugs against the RHEL, +since they were 1:1 distros (minus the branding and support). So you'd +technically get RHEL free of charge. + +Benefit of such project, except for the cost, is questionable. The main issue, +which actually became even more apparent after changing the flow, is someone +else repackaging your own product and selling it again. + +#### After the change + +First of all, the current flow counters the issue mentioned above. You can test +your projects against the _next minor RHEL release_. CentOS Stream is free, so +you can freely incorporate it into your CI pipelines. + +:::tip Shameless plug pt. 2 + +Again, [Packit] can help you on upstream to verify that you're not breaking your +RPM builds and on top of that you can also use [Testing Farm] to run tests on a +specific Fedora or CentOS Stream releases. + +> Green tests may not be green everywhere and catching such issues as soon as +> possible costs much less than catching them further down the chain. + +::: + +There are many people thinking that RHEL has become closed-source. It is not. +The development happens _out in the open_, it's more open that it was before. +However with the cost of not getting the exact same thing for free. You can get +the next minor RHEL, not the same that's normally paid for. [Packit] is an +example of a service that is deployed on the CentOS 9 Stream and even used to be +deployed on Fedora, but the regular 6-month release cycle caused some minor +issues here and there. + +_Production-ready_ is something that heavily depends on the context… + +:::tip Free “clones” + +After this change so-called _free “clones”_ emerged. I have to admit that in +case of _[AlmaLinux]_ I can see some benefits e.g., pushing for live images and +support of various desktop environments, Raspberry Pi support or even WSL images +being present in the M$ Store and easy to install. + +::: + +## Open-source and paid support + +Overall I don't think that paying for the support of 5 years old _non-critical_ +packages is going against the open-source. It is a non-trivial work that, in +majority of cases, cannot be included in the upstream, therefore the benefit is +reapt only by the paying customers. I have to admit that in the case of the +Ubuntu Pro it may seem a bit weird (hiding patches behind the paywall). However +we're still talking about rather big set of packages that will affect a minority +of server workloads, if any. + +## Glossary + +- _rolling release_ - continuously released without “significant milestones” + + :::tip + + As an example of rolling distribution you can take archLinux, openSUSE + Tumbleweed, Fedora Rawhide, or even CentOS 9 Stream. + + As en example of **not** rolling distribution you can take Ubuntu, openSUSE + Leap or Fedora. + + ::: + +- _bleeding edge_ - contains the latest versions as they are released on the + upstream + + :::tip + + As an example you can take archLinux, openSUSE Tumbleweed or Fedora Rawhide. + You can also notice how common it is to combine _rolling release_ with + _bleeding edge_. + + ::: + +- _upstream_ & _downstream_ + + You're most likely to meet these terms in the meaning of upstream being the + project itself and downstream being the packaging of said project in some + distribution. + + However this can also apply to distributions like _openSUSE Tumbleweed_ with + _openSUSE Leap_, _Fedora_ with _CentOS Stream_, or even _CentOS Stream_ with + _RHEL_. This basically means that the packages/software is being released into + the upstream (Tumbleweed, Fedora, or even CentOS) and then after being tested + is taken further down into their respective downstreams (Leap, CentOS, RHEL). + +[almalinux]: https://almalinux.org/ +[alp]: https://susealp.io/ +[distrobox]: https://distrobox.it/ +[emacs]: https://src.fedoraproject.org/rpms/emacs/ +[packit]: https://packit.dev/ +[podman]: https://podman.io/ +[testing farm]: https://docs.testing-farm.io/Testing%20Farm/0.1/index.html +[toolbx]: https://containertoolbx.org/ +[ubuntu pro]: https://ubuntu.com/pro/ +[zorin os]: https://zorin.com/os/pro/ + +[^1]: Richard Stallman +[^2]: directed acyclic graph +[^3]: + Ubuntu Pro is technically a service whereas the RHEL and SLE are distros + with the support included. + +[^4]: + There are upstream projects that keep LTS branches, such as Linux kernel, + but even in the case of the kernel itself, they're planning on ending it, + since the cost outweighs the benefits at this point.