Re: [gentoo-user] systemd and kernel developers cooperating to turn it into a global cgroup manager?

[Samuli Suominen]

On 20/10/13 13:47, Daniel Campbell wrote:
> On 10/20/2013 04:55 AM, Samuli Suominen wrote:
>> On 20/10/13 12:24, Daniel Campbell wrote:
>>> On 10/20/2013 02:37 AM, Samuli Suominen wrote:
>>>> On 20/10/13 09:34, Daniel Campbell wrote:
>>>>> On 10/19/2013 06:35 PM, Volker Armin Hemmann wrote:
>>>>>> Am 19.10.2013 17:02, schrieb Daniel Campbell:
>>>>>>> On 10/17/2013 11:27 PM, Mark David Dumlao wrote:
>>>>>>>> https://www.linux.com/news/featured-blogs/200-libby-clark/733595-all-about-the-linux-kernel-cgroups-redesign
>>>>>>>>
>>>>>>>> Not sure if I read that just right... but since nobody is doing cgroup
>>>>>>>> management besides systemd, in practice the cgroups implementation in
>>>>>>>> Linux wasn't very consistent. So since systemd is doing it, their work
>>>>>>>> is helping shape the kernel's cgroups api?
>>>>>>>>
>>>>>>>> Interesting...
>>>>>>>>
>>>>>>> >From my perspective it looks like systemd developers are trying to push
>>>>>>> their ideas into the kernel, almost like they intend to merge systemd
>>>>>>> *with* the kernel.
>>>>>> from what I read in the article cgroups are a mess and are cleaned up
>>>>>> anyway. The only real user of cgroups at the moment is systemd.
>>>>>> Others are welcome to make use of cgroups too. But in the current state
>>>>>> nobody blames them for not jumping in.
>>>>> No complaints here in improving something, but consider the source is
>>>>> all I'm saying.
>>>>>
>>>>>>> If systemd is the only implementation of cgroups and
>>>>>>> their developers are working on cgroup support in the kernel, it spells
>>>>>>> calamity given their history of evangelism and zealotry.
>>>>>> well, going over some old ml threads on fedora mailing lists all I could
>>>>>> find was that Poettering and Sievers DID listen and DID make changes if
>>>>>> the demand was high enough.
>>>>>>
>>>>>> Sure, I dislike systemd. Sure what happened with udev was a dick move.
>>>>>> But their 'zealotry' is a lot less developed than the zealotry of those
>>>>>> who exploded about using an 'init-thingy' in the future.
>>>>>>
>>>>> I'd say their zealotry is less loud and more persistent. Their way is
>>>>> best, UNIX (and its philosophy) is outmoded, people are thinking 30
>>>>> years behind where we are, etc etc etc. Those who have separate /usr and
>>>>> blame systemd for pushing them to use an initramfs aren't seeing the
>>>>> real problem (upstreams not putting things where they belong, FHS no
>>>>> longer *really* being worked on, generally just the filesystem being
>>>>> played with like a toy)
>>>>>
>>>>>>> I truly wish I understood why a single userland program and its
>>>>>>> developers are being given the keys to an entire subsystem of the
>>>>>>> kernel.
>>>>>> they aren't.
>>>>> Of the people who have committed to the cgroup subsystem of the kernel,
>>>>> how many are not members of the systemd, GNOME, or Red Hat projects?
>>>>> I'll let that speak for itself.
>>>>>
>>>>>>> Their changes to udev have proven to be a headache for users,
>>>>>> yes? which ones?
>>>>> Persistent NIC naming, for starters. The former maintainer's idea to
>>>>> merge with systemd (which was influenced by Mr. Poettering in the first
>>>>> place) when the two are completely separate pieces of software that do
>>>>> two completely different jobs, and various other troubles with udev >
>>>>> 175 that one can Google for and find tons of results.
>>>> I can't find anything that would be true. Can you point out some?
>>>> A lot of FUD[1] and outright lies coming from people, who, for example,
>>>> don't like systemd.
>>>>
>>>> [1] http://en.wikipedia.org/wiki/Fear,_uncertainty_and_doubt
>>>>
>>>> I know for a fact udev-208 is a full replacement for udev-171 in terms
>>>> that both work on same kernels, same libcs, and so forth. That's why
>>>> 171 is no longer in Portage, because it's completely useless from users
>>>> (and developers) point of view.
>>>>
>>>> Adjusting some configs and enabling some kernel options that have been
>>>> around for a long time is just part of normal maintenance process,
>>>> that's what we have admins for.
>>>>
>>> Do you know the design consequences of opt-in versus opt-out? I'll keep
>>> this short: When evolving a codebase, new behavior for core parts of the
>>> system should not be pushed or forced on users. If you must, keep the
>>> old behavior around as a default and allow users to try the new thing by
>>> explicitly opting in. The new naming in whichever udev started the mess
>>> did it the exact opposite (and wrong) way.
>>
>> It's not forced upon you. You received a news item that had instructions
>> on howto assign names you want, like lan0, internet1, wireless3, and so
>> forth.
>> And it also described howto turn off udev from completely renaming the
>> devices, to keep kernel assigned names.
>> What they did was they dropped the *broken* feature called 'persistent
>> rule_generator' which never worked correctly, and in
>> race conditions still flipped eth0 <-> eth1 around -- that was a
>> *security* flaw that *needed* to go.
>> It would have gone even without providing the alternative of providing
>> biosdevname -like new name optionality to the users.
>> Kernel and kernel drivers are designed in a way it's not supported to
>> flip in-place kernel names and udev tried to workaround that.
>>
>> https://www.kernel.org/doc/htmldocs/device-drivers/API-device-rename.html
>>
> Like I mentioned in a prior e-mail, the change didn't affect me when it
> was pushed, and doesn't affect me now. I did recently have to reinstall
> Gentoo, however (note, going from testing to stable isn't fun ;p), and
> noticed it when I found Gentoo ships with systemd-udev instead of eudev.

Yep, no plans on changing the default sys-fs/udev to anything else, no
reason to.

> I got the new naming and had to do some work to go back to what should
> be normal behavior. My `kernel` line remains with that switch in effect,
> but I'm not sure if eudev requires that flag to keep default behavior.
> Had udev's defaults been left alone, I wouldn't have had to go through
> any trouble to migrate back to eudev beyond the unmerge and emerge
> that's expected as part of a switch. That's where the design flaw rears
> its ugly head. I could see opposition to my view if I was trying to do
> something that the software simply wasn't designed to do, like cook my
> breakfast for me. Regardless, I was speaking purely from a design
> perspective; I succeeded in solving the problem (mostly) on my own, so
> no issues there.
>
> Perhaps the next time I need to install Gentoo, I'll find a way to get
> eudev on there before even the first proper boot and avoid the problem
> altogether.

It's true that sys-fs/eudev restored the *broken* rule_generator from
old sys-fs/udev, you can get it by USE="rule-generator".
But it's lot saner to keep using sys-fs/udev and just write custom rules
to rename interfaces based on MACs to like lan*, internet*
so all in all, currently, using sys-fs/eudev doesn't make sense unless
you are experimenting/developing for it.
For single NIC system, as you mentioned, you can just keep using
sys-fs/udev and use the kernel net.ifnames=0 parameter to keep
the interface at eth0.
Maybe there will be some differences in future that makes eudev
worthwhile, but that remains to be seen.

>>> *multi-NIC* use that wasn't as predictive and needed the fix, not
>>> *single*. It's basically using poor design/defaults decisions to smear
>>> existing technology dishonestly. Technical propaganda, so to speak.
>>>
>>> My beef with that decision is separate from my disdain for the decision
>>> to merge it with systemd, which is only mildly related to why I dislike
>>> systemd, but that's irrelevant.
>>>
>>> As for FUD, I see no reason to get personal. If you insist, we can take
>>> a look at which Gentoo package(s) you maintain that are related to the
>>> topic and ask ourselves if you are any less biased.
>>>
>> If you are hinting I'm someway favouring systemd, or udev for that
>> matter, you couldn't be more wrong. I use OpenRC, and I maintain
>> ConsoleKit/udev
>> out of necessity (because someone has to). I deal with facts, I have no
>> favouritism to any direction.
>> In contrast, I also maintain a bunch of software that allows people to
>> *skip* whole freedesktop.org stack (ConsoleKit, PolicyKit and so forth)
>> like pmount,
>> pmount-gui and such for minimal systems.
>>
> So you maintain them, but don't necessarily follow or agree with their
> goals/sentiments/designs? Does that ever create problems for you when
> trying to test systemd/udev on revbumps and whatnot? Do systemd
> proponents wonder why you don't use what you maintain? Honestly curious;
> I assumed that if you maintain something, you use it. Perhaps I was wrong.

Well, there is also the difference of liking something and using it for
myself at home and then using something
at work because it's just the quickest and cleanest way of achieving
something.
But of course I test everything boot related before committing them to
users. ;-)
There is really no conflict, I'm luckily in a position where I have
access to hundreds of systems.
But also that, what you said, it's possible to maintain something
without using it, that is to be determined package-by-package basis.