The Linux Questions Thread: a bunch of pitfalls, but technically it's possible

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > The Linux Questions Thread: a bunch of pitfalls, but technically it's possible

«‹›1024 »

taqueso: Mar 8, 2004

D. Ebdrup posted:

Huh, that's quite impressive.

As far as I know, the non-snapshot volume continues to work though

# ? May 10, 2020 21:52

Adbot: ADBOT LOVES YOU

# ? Apr 19, 2024 18:49

Antigravitas: Dec 8, 2019; Die Rettung fuer die Landwirte:

quote:

Would you like to merge these packages? [Yes/No] y
Sorry, response 'y' not understood. [Yes/No] y
>>> Verifying ebuild manifests
>>> Running pre-merge checks for acct-group/lpadmin-0
�

# ? May 11, 2020 15:39

Combat Pretzel: Jun 23, 2004; No, seriously... what kurds?!

Just trying to update my Pi Hole VM running ubuntu 18.10 to the latest release, and it's not loving supported. Well, thank you Ubuntu! Now I have to hack some dumb poo poo on UpdateManager to make it work.

# ? May 11, 2020 17:01

BlankSystemDaemon: Mar 13, 2009

quote:

If the snapshot logical volume becomes full it will be dropped (become unusable)

It gets even better, because there's the almost undocumented /etc/lvm/lvm.conf:snapshot_autoextend_threshold variable which appears to default to 100, and even if you change it, it's buggy (for all Ubuntu forks, and maybe all Debian forks?).

# ? May 11, 2020 19:37

Powered Descent: Jul 13, 2008; We haven't had that spirit here since 1969.

I've just realized I missed the opportunity to make a chmod joke on page 777.

# ? May 11, 2020 19:49

MrPablo: Mar 21, 2003

fletcher posted:

Trying to write a little bash script that will ssh to a remote server, switch to the postgres user, and then run psql with some command.

I got as far as:
code:
ssh -t my-db-server "sudo su postgres -c 'cd /var/lib/pgsql; psql'"
That works and gets me to the psql command prompt at least

So now I need to change it to feed the command I want to run with psql -c

The command I want to run is:
code:
\copy (SELECT schema_name FROM information_schema.schemata WHERE schema_name LIKE '\_%' ORDER BY schema_name) TO '/tmp/whatever.csv' WITH CSV HEADER
I'm getting lost in a mess of trying to escape quotes though, can't help but think there's another way to go about this?

I'm a few months late here, but for that particular query I wouldn't even bother SSHing into the database server; instead, I would do the following:

Create a database role with a password that can log in to the postgres database (example: "CREATE ROLE schema_dumper WITH LOGIN PASSWORD 'gah8soo:X2AL';")
Add an entry to pg_hba.conf that allows the database role to connect via TCP from the IP address of the source machine.
Use psql from the source machine to connect to the database server and execute the query (example: "psql -h my-db-server -U schema_dumper postgres <<EOF ...")

(The general idea here is to limit the attack surface, and a read-only database account that's only accessible remotely from a single IP address is a smaller attack surface than an SSH account).

Another tip: The information_schema schema in postgres is a series of views and they are notoriously slow; if you just need a list of schema names that begin with an underscore, then it's faster to query pg_namespace directly, like this:

code:

SELECT nspname
  FROM pg_namespace
 WHERE nspname LIKE '_%'
 ORDER BY nspname

# ? May 11, 2020 21:15

BlankSystemDaemon: Mar 13, 2009

Powered Descent posted:

I've just realized I missed the opportunity to make a chmod joke on page 777.

What a terrible night to have such a curse!

# ? May 11, 2020 22:25

trilobite terror: Oct 20, 2007; BUT MY LIVELIHOOD DEPENDS ON THE FORUMS!

Can somebody recommend me a desktop OS? I�m using the 4gb rPi4. So far I�ve looked at raspbian, Ubuntu, and manjaro but I�m a bit confused by KDE vs XFCE, Ubuntu vs LUbuntu/etc, and so on. It also seems like the only version of Ubuntu supported by canonical on rpi is Ubuntu Server, am I going to see a practical difference? Should I just stick to Raspbian?

# ? May 13, 2020 20:13

MrPablo: Mar 21, 2003

Ok Comboomer posted:

Can somebody recommend me a desktop OS? I�m using the 4gb rPi4. So far I�ve looked at raspbian, Ubuntu, and manjaro but I�m a bit confused by KDE vs XFCE, Ubuntu vs LUbuntu/etc, and so on. It also seems like the only version of Ubuntu supported by canonical on rpi is Ubuntu Server, am I going to see a practical difference? Should I just stick to Raspbian?

This is probably a better question for the Raspberry Pi thread, but my recommendation would be to stick with Raspbian.

Raspbian comes with a desktop environment out of the box, has a large selection of packages, and it will make it far easier for you to find answers to any questions you might have than any other distribution.

# ? May 13, 2020 21:01

Chilled Milk: Jun 22, 2003; No one here is alone,
satellites in every home

Ok Comboomer posted:

Can somebody recommend me a desktop OS? I�m using the 4gb rPi4. So far I�ve looked at raspbian, Ubuntu, and manjaro but I�m a bit confused by KDE vs XFCE, Ubuntu vs LUbuntu/etc, and so on. It also seems like the only version of Ubuntu supported by canonical on rpi is Ubuntu Server, am I going to see a practical difference? Should I just stick to Raspbian?

I would stick with Raspbian until you know you have a good reason not to.

# ? May 13, 2020 21:05

a dmc delorean: Jul 2, 2006; Live the dream

I've been using Solus (MATE) for a couple of months and whilst I quite liked it, I didn't like the lacking repos.

Switched to Pop!_OS, installed KDE, and it seems really good, despite its silly name

# ? May 13, 2020 23:22

Severing: Aug 26, 2017

Antigravitas posted:

If you want a personal RHEL you use CentOS, which is RHEL with the branding replaced.

Is there a reason one would do this over say just running Fedora these days?

Just curious what the difference would be aside from branding and being more bleeding edge.

# ? May 17, 2020 18:30

minato: Jun 7, 2004; cutty cain't hang, say 7-up.; Taco Defender

Fedora updates to a new major version every 6 months and go end-of-life after about a year. CentOS and RHEL update far less frequently and go end-of-life after a Very Long Time.

# ? May 17, 2020 19:48

Matt Zerella: Oct 7, 2002; Norris'es are back baby. It's good again. Awoouu (fox Howl)

Fedora in the streets (desktop) RHEL/CentOS in the sheets (server)

# ? May 17, 2020 19:56

nem: Jan 4, 2003; panel.dev
apnscp: cPanel evolved

Great for servers so you don�t have to play upgrade hopscotch every 18 months when a vulnerability drops that isn�t patchable in that release of Fedora. As a secondary benefit, each CentOS release ages and picks up a ton of very specific fixes you can quickly Google. Stuck on Fedora 30 and stumbled across some very specific kernel bug? It�s much easier to find someone else with that specific scenario on CentOS x than an ephemeral Fedora release.

# ? May 17, 2020 19:59

Antigravitas: Dec 8, 2019; Die Rettung fuer die Landwirte:

Also, Fedora is where all the exciting new stuff happens.

Excitement is the last thing I want in my infrastructure. I want boring, dependable.

# ? May 17, 2020 21:27

Chilled Milk: Jun 22, 2003; No one here is alone,
satellites in every home

Matt Zerella posted:

Fedora in the streets (desktop) RHEL/CentOS in the sheets (server)

☝☝☝

# ? May 17, 2020 22:56

Severing: Aug 26, 2017

I see through a bit of research Fedora does not offer an LTS version, so that makes sense.

# ? May 18, 2020 11:09

xtal: Jan 9, 2011; by Fluffdaddy

I imagine Fedora, RHEL and CentOS are objectively the best distributions because they are backed by Red Hat who effectively privatized Linux. You're gonna use systemd anyway, might as well use the OS it was made for. That scope creep didn't stop there.

xtal fucked around with this message at 11:24 on May 18, 2020

# ? May 18, 2020 11:22

Matt Zerella: Oct 7, 2002; Norris'es are back baby. It's good again. Awoouu (fox Howl)

Ive played around with Fedora on the desktop on my t460s laptop and its pretty drat good.

And yeah, through work I've definitely come to appreciate Centos/RHEL on the server side. The only other distro I'd consider server side would be Debian stable, and even then it would only be if for some reason something has better support on Deb based distro (for example I run docker on Debian now since Centos8 basically dropped it).

# ? May 18, 2020 15:30

Hollow Talk: Feb 2, 2014

xtal posted:

I imagine Fedora, RHEL and CentOS are objectively the best distributions because they are backed by Red Hat who effectively privatized Linux. You're gonna use systemd anyway, might as well use the OS it was made for. That scope creep didn't stop there.

Redhat or SuSE are the way to go, imho, since they both are very active upstream (or are upstream). They also collaborate on a bunch of cloud native and container things, and people there generally know what they are doing (cf. OBS).

One of the customers I work for has a mixed Debian/Ubuntu infrastructure, and I can't fathom why one would want to do that.

# ? May 21, 2020 21:24

CaptainSarcastic: Jul 6, 2013

Hollow Talk posted:

Redhat or SuSE are the way to go, imho, since they both are very active upstream (or are upstream). They also collaborate on a bunch of cloud native and container things, and people there generally know what they are doing (cf. OBS).

One of the customers I work for has a mixed Debian/Ubuntu infrastructure, and I can't fathom why one would want to do that.

Yeah, I've been really happy with OpenSUSE for years now.

I developed a (probably semi-irrational) preference for RPM distros back in the days of Mandrake, and mostly stuck with it since.

# ? May 21, 2020 21:59

Antigravitas: Dec 8, 2019; Die Rettung fuer die Landwirte:

Mixed infra is terrible, but pure Debian is fine. It's what I've inherited, it does the job.

Mixing really is hell though. We had one CentOS VM for a while and I could finally get rid of it. It had a fork of our Ansible repo just for itself but I had to do a lot of work to make it run, and it still didn't run all that well because we rely heavily on distro defaults and only put modifications on top. RHEL and Debian have some interesting differences.

One fun difference is that Debian does not trust the kernel keyring for the Kerberos credential cache and everything uses file-based ccache, but RHEL uses the keyring, and it broke tgt ticket renewal on that single VM�

I don't like diagnosing Kerberos issues.

# ? May 21, 2020 23:03

Computer viking: May 30, 2011; Now with less breakage.

Antigravitas posted:

I don't like diagnosing Kerberos issues.

Oh god no.
Extra fun if the server is AD, and you don't have any access to it except enough rights to add and modify accounts.

# ? May 22, 2020 00:20

Antigravitas: Dec 8, 2019; Die Rettung fuer die Landwirte:

Oh yes, I only have access to an OU in AD. We used to have our own domain but that's even more tedious.

In my case though pam_krb5.so came before pam_winbind.so in the pam stack, so pam_krb5.so would authenticate an account, create a credential cache (in keyring), and pam_winbind.so was just called for session init etc.

So for 4 hours, everything would work, and then all NFS mounts became inaccessible to users because the tgt ran out and didn't get renewed by winbind�while renewal worked fine on all Debian hosts�

Another fun one: Some knucklehad decided to put the student group into one of their own groups. I.e. all students are automatically in a group of one of the institutes.

That means if you try to resolve all nested groups of a student you get a few groups that contain all students.

Now if you know your POSIX you are probably cringing already, but to spell it out: The syscall to get a group returns an array of all members.

We have close to 100 000 users in AD, mostly students.

Luckily, you can break with POSIX in this case, but cripes�

# ? May 22, 2020 09:22

Computer viking: May 30, 2011; Now with less breakage.

Yup, that all sounds unpleasantly familiar. Except the groups, I did fortunately not run into that.

# ? May 22, 2020 12:28

mystes: May 31, 2006

Is anyone using GPU passthrough with Looking Glass? I'm thinking of trying consolidating from a linux computer and a windows computer with multiple monitors and barrier for keyboard/mouse sharing to one 4k monitor attached to a linux computer with windows running in a vm.

# ? May 24, 2020 16:45

BlankSystemDaemon: Mar 13, 2009

I discovered and documented how to get rid of pulseaudio for video-conferencing on FreeBSD, including how to do multi-device mixing using FreeBSDs in-kernel sound mixing and sndiod, for when you've got microphone and speakers on separate devices.
FreeBSD has apparently been capable of this for over a decade.

# ? May 25, 2020 20:35

other people: Jun 27, 2004; Associate Christ

what's a bsd?

# ? May 25, 2020 21:43

trilobite terror: Oct 20, 2007; BUT MY LIVELIHOOD DEPENDS ON THE FORUMS!

Ok Comboomer posted:

a big sexy dad

ah see this makes sense to me

# ? May 25, 2020 21:58

BlankSystemDaemon: Mar 13, 2009

Ok Comboomer posted:

a big sexy dad

Holy gently caress, I love it!
Mods, Admins? Anyone? Please change my name to Big Sexy Dad!

# ? May 25, 2020 23:36

CaptainSarcastic: Jul 6, 2013

Has the audio thing been a problem in Linux? I've had to run Zoom videoconferences for work and had no problem changing microphones and speakers in pulseaudio.

# ? May 26, 2020 00:07

BlankSystemDaemon: Mar 13, 2009

CaptainSarcastic posted:

Has the audio thing been a problem in Linux? I've had to run Zoom videoconferences for work and had no problem changing microphones and speakers in pulseaudio.

PulseAudio (and to a lesser degree ALSA) is an absolute pain to work with when you're doing complicated audio stuff. OSS or sndio aren't.

# ? May 26, 2020 00:56

taqueso: Mar 8, 2004

Pulseaudio is really nice to work with in my experience, and complex setups are kinda it's thing

And audio has been fine in Linux for years, the alsa pulse switch had some issues but that was like a decade ago

# ? May 26, 2020 01:03

Varkk: Apr 17, 2004

taqueso posted:

Pulseaudio is really nice to work with in my experience, and complex setups are kinda it's thing

And audio has been fine in Linux for years, the alsa pulse switch had some issues but that was like a decade ago

Yes but Lennart and systemd you see and furthermore Reeeeeeeeee!

I thought that pulseaudio was created to overcome issues with oss and alsa in regards to more complex setups etc. A couple of distros pushed it before it was ready so it didn�t have a great introduction. From memory Fedora used it as default before the developers said it was ready to be used.

# ? May 26, 2020 01:27

CaptainSarcastic: Jul 6, 2013

Aside from having to remember to install the pulseaudio mixer I really haven't had Linux audio problems in years. I definitely remember having to deal with way more fuckery using ALSA.

# ? May 26, 2020 01:37

ewe2: Jul 1, 2009

Varkk posted:

Yes but Lennart and systemd you see and furthermore Reeeeeeeeee!

This is stupid and unhelpful, grow up.

quote:

I thought that pulseaudio was created to overcome issues with oss and alsa in regards to more complex setups etc. A couple of distros pushed it before it was ready so it didn�t have a great introduction. From memory Fedora used it as default before the developers said it was ready to be used.

It's not a bad API but there was no idea how to integrate it at a system level, it was basically left to users to guess how to integrate it with applications, which is why its adoption has been so loving painful. That's why developers like Lennart are both a blessing and a curse if they don't have good management making the best use of their output, and Lennart hasn't been served well by his employers. I think they did a better job with systemd but it's a second-system effect and they've gone overboard, leading to a backlash.

It doesn't matter whether you think that's deserved or not, its just what happened and it's a reason why companies are closing in and demanding a piece of the Linux pie to integrate because there's been no effective leadership from the distros which could have averted a lot of this.

Until I started using Reaper, I didn't think it was possible to use pulseaudio in a serious way because every other application half-assed the job of integration, forcing you to either use alternate configs (Discord and some mixer requirements) or choosing to drop back to ALSA entirely (Audacity was a big culprit for a long time and it still can't manage latency intelligently) or forced restart/reloading (VLC). Still a long way to go.

# ? May 26, 2020 02:21

Nostalgia4Butts: Jun 1, 2006; WHERE MY HOSE DRINKERS AT

ive got an old powerbook g5 thats still running, kinda was thinking about replacing OSX with something lightweight that can handle youtube, internet browsing, and discord (browser mode is fine).

I have no other uses or needs for the system, just wanted something i can throw next to me when im playing games online to chat or play videos. Any recommendations?

# ? May 26, 2020 05:31

Adbot: ADBOT LOVES YOU

# ? Apr 19, 2024 18:49

CaptainSarcastic: Jul 6, 2013

It's been years since I played with a PPC-based system. About 10 years ago I had good luck with the PPC spin of openSUSE (I think that might have actually been the first time I actually ran openSUSE at all).

At this point I'm not sure what distros have PPC versions available, be they official or unofficial.

If memory serves the biggest thing it was missing was Flash, but that's so deprecated it doesn't seem like a big issue compared to how much of a problem it was at the time.

You could always scrounge up an old image of Yellow Dog. I never had a good experience with Yellow Dog even when it was current.

Fake edit: I did a quick search and it looks Ubuntu doesn't have a recent PPC build, but it looks like openSUSE does.

https://en.opensuse.org/Portal:PowerPC

I'm not sure, but it might be possible to find a BSD to install on PPC, too, but I didn't look extensively.

# ? May 26, 2020 05:52

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > The Linux Questions Thread: a bunch of pitfalls, but technically it's possible

«‹›1024 »