In search of an appropriate RLIMIT_MEMLOCK default

Posted Nov 24, 2021 8:53 UTC (Wed) by nilsmeyer (guest, #122604)
In reply to: In search of an appropriate RLIMIT_MEMLOCK default by NYKevin
Parent article: In search of an appropriate RLIMIT_MEMLOCK default

I'm just describing what I've seen in the wild. Of course having the cattle approach and an orchestration system and competent admin/SRE teams is better(tm), but that's just not the reality for a lot of organizations I've seen from the inside - granted that's usually why I'm asked to take a look in the first place.

In search of an appropriate RLIMIT_MEMLOCK default

Posted Nov 25, 2021 9:44 UTC (Thu) by NYKevin (subscriber, #129325) [Link] (5 responses)

I entirely agree. In fact, that's actually my whole point - defaults are used by lots of sysadmins, most of whom are not really in a position to come up with their own settings (at least, not without a lot of manual profiling and other busywork that most sysadmins frankly are not going to get around to doing). When the kernel developers say "I dunno, let's just make it the sysadmin's problem," in practice this actually means that many systems will be poorly configured, unless or until the misconfiguration gets so egregiously bad that someone with the authority to do so actually files a P1 ticket (or Urgent, or whatever label your ticketing system uses for "we actually care about this one").

The cattle people, by contrast, don't care about rlimit defaults in the first place, because they just ingest the dimension into their existing resource management system and automate the whole problem away. So in a sense, these defaults are a pets-only affair, and you need to take a realistic view of what a pet-shop sysadmin can plausibly do in terms of tuning arcane system parameters that they likely have never even heard of. Of course, plenty of pets are actually workstations, or laptops, or other such non-server devices,* in which case the sysadmin is probably either a SWE or the IT department, and might not even speak fluent bash, let alone know what an "rlimit" is supposed to be.

* I'm ignoring Android and Android-like devices because I assume that Google or whoever will extensively customize absolutely everything, and pick sane defaults (or at least, defaults that are not obviously ridiculous). Also, it would not really make sense for Linus and co. to try and guess how to tune Linux to perform well on a smartphone.

In search of an appropriate RLIMIT_MEMLOCK default

Posted Nov 25, 2021 13:03 UTC (Thu) by Wol (subscriber, #4433) [Link] (4 responses)

> The cattle people, by contrast, don't care about rlimit defaults in the first place, because they just ingest the dimension into their existing resource management system and automate the whole problem away. So in a sense, these defaults are a pets-only affair, and you need to take a realistic view of what a pet-shop sysadmin can plausibly do in terms of tuning arcane system parameters that they likely have never even heard of. Of course, plenty of pets are actually workstations, or laptops, or other such non-server devices,* in which case the sysadmin is probably either a SWE or the IT department, and might not even speak fluent bash, let alone know what an "rlimit" is supposed to be.

And you're forgetting people like me, who run a home server, so just like MS pisses me off with the error message "contact your system administrator", you're doing the same telling me to "contact yourself to fix the problem", WITHOUT giving me any clues as to what the problem is, or how to solve it.

So the equivalence "pet-shop admin == end user without a clue" is largely true. You're just throwing these people under the bus, but the reality is these people are also VERY IMPORTANT in the PR war. We run linux from choice, and our contribution is political, not technical ...

Cheers,
Wol

In search of an appropriate RLIMIT_MEMLOCK default

Posted Nov 26, 2021 0:25 UTC (Fri) by NYKevin (subscriber, #129325) [Link] (3 responses)

While I'm quite sure that YOU speak fluent bash, since you read and comment on LWN articles, there are plenty of SWEs who can barely function in a non-GUI environment. It's actually kind of terrifying to me, but in a creeping existential dread sort of way.

In search of an appropriate RLIMIT_MEMLOCK default

Posted Nov 26, 2021 11:16 UTC (Fri) by farnz (subscriber, #17727) [Link] (1 responses)

I went along to my employer's optional internal training on being productive with the command line, and was surprised by how much of what my fellow attendees thought was "amazing information" was stuff I considered basic CLI knowledge.

CLIs just aren't the normal form of interaction for modern programmers, most of the time, and thus the basics aren't being learnt (or taught).

In search of an appropriate RLIMIT_MEMLOCK default

Posted Nov 30, 2021 16:32 UTC (Tue) by nix (subscriber, #2304) [Link]

This has, of course, been true for decades. The stuff at the start of Charlie Stross's _The Atrocity Archive_ involving a necromantic summoning training course in which our protagonist has exactly the same realisation was drawn directly from, er, life -- and that was written in the year 2000...

In search of an appropriate RLIMIT_MEMLOCK default

Posted Nov 26, 2021 13:07 UTC (Fri) by Wol (subscriber, #4433) [Link]

Actually, I *DON'T* speak fluent bash. My scripting language of choice would be an obsolete language called CPL (Command Procedure Language). I think there are a few Pr1mates here who would recognise it :-)

sed, grep, awk, etc are all power tools I have never really got to grips with, because I've never been in an envioronment where they were either (a) the goto tools, or (b) my colleagues were familiar with them.

And while I've forgotten most of my CPL, it had a lot of power capabilites that were the equivalent.

But yes, I did grow up and cut my computing teeth in a time before guis like X and Windows. It just wasn't in a nix environment, which is why I'm so damning of (li)nux sometimes - I feel it's a case of "Unix won because it was good enough and cheap enough". Doesn't stop it being crap :-)

Cheers,
Wol