Ubuntu Linux Jail on FreeBSD 12.2-Release • Hacker News Board

Re: Ubuntu Linux Jail on FreeBSD 12.2-Release

#71

Post by Denvercoder9 » Tue, Nov 03, 2020, 1:28 PM UTC

zrm wrote: post #52

Denvercoder9 wrote: post #46

Earlier quoted context omitted.

People keep saying it's tightly coupled, but never supply any proof for that. You can still run udev without systemd, the NTP stuff is completely optional and in separate binaries and the same is true for the network management stuff. The journal is indeed required, but any traditional syslog daemon still works, and you can trivially disable the persistent journal (I even believe that's the default on Debian).

Suppose I want to write my own competitor to systemd-resolvd. I want it to work with systemd-networkd, in the same way as systemd-resolvd does. Or just patch dnsmasq or unbound to be able to do that. Is there a stable interface for that? An RFC I can read? Any guarantee they won't change the interface and break my version, while they update both of theirs together?

Judging from the manpage and a quick look at the code, the only thing for which systemd-networkd and systemd-resolved interact is to get the DNS servers pushed over DHCP, which it does over the D-Bus interface that falls under the interface stability promise[1].

[1] https://systemd.io/PORTABILITY_AND_STABILITY/

Re: Ubuntu Linux Jail on FreeBSD 12.2-Release

#72

Post by trasz » Tue, Nov 03, 2020, 1:34 PM UTC

markstos wrote: post #11

Nice progress, but it notes that `systemd` doesn't work, which means all the things that depend on `systemd` won't work either.

The main purpose of Linuxulator is to run software that's not available natively, which basically means closed-source software, eg. Steam, or native Chrome, or Eagle. Pretty much none of it depends on systemd.

What you would need systemd for is virtual machines - and that case is better handled by just running Linux under bhyve(8).

Re: Ubuntu Linux Jail on FreeBSD 12.2-Release

#73

Post by Denvercoder9 » Tue, Nov 03, 2020, 1:41 PM UTC

arminiusreturns wrote: post #51

Denvercoder9 wrote: post #46

Earlier quoted context omitted.

People keep saying it's tightly coupled, but never supply any proof for that. You can still run udev without systemd, the NTP stuff is completely optional and in separate binaries and the same is true for the network management stuff. The journal is indeed required, but any traditional syslog daemon still works, and you can trivially disable the persistent journal (I even believe that's the default on Debian).

Please checkout the progression of Devuan if you are wanting to understand just how viral systemd is in modern linux. If it wasn't so tightly coupled, why did it take 2 years to decouple it? https://sysdfree.wordpress.com/2017/08/16/112/ https://nosystemd.org/

First of all, Devuan wants to get rid of any and all systemd code. This includes for example libsystemd-daemon0, which is a tiny library that implements the stable notification protocol and is a no-op on systems not running systemd. You can reimplement it yourself in pretty much any language, but lots of programs just link against the systemd library because it's easier and has no tangible downside, even for people not running systemd. Eliminating such dependencies isn't particulary hard but takes a lot of work. Likewise, the rest of the world has left SysV init scripts behind, so they have to write those too.

The second reason is that systemd provides features for which there simply is no alternative. Desktop environments are entangled with logind, because it's the only software providing that functionality. Before logind they had a hard dependency on ConsoleKit, which was pretty much abandoned. Reimplementing all these features takes time.

Re: Ubuntu Linux Jail on FreeBSD 12.2-Release

#74

Post by big-malloc » Tue, Nov 03, 2020, 2:30 PM UTC

takeda wrote: post #39

jdc wrote: post #23

Earlier quoted context omitted.

macOS seems to do alright

MacOS runs a VM with Linux installation on it. That's why it takes so long to start, it is slow and uses so much CPU power and memory to run.

Not to mention the unusable volume performance

Re: Ubuntu Linux Jail on FreeBSD 12.2-Release

#75

Post by nickik » Tue, Nov 03, 2020, 3:02 PM UTC

bee_rider wrote: post #14

markstos wrote: post #11

Nice progress, but it notes that `systemd` doesn't work, which means all the things that depend on `systemd` won't work either.

I've been generally OK with systemd, and think most of the complaints about it were over-dramatic, but this is exactly one of the things we were warned about, right?

systemd provides process and resource isolation. You can either have something comparable with everything or something the uses specific features of the kernel. You just can't have it all.

Re: Ubuntu Linux Jail on FreeBSD 12.2-Release

#76

Post by trasz » Tue, Nov 03, 2020, 3:04 PM UTC

dddddaviddddd wrote: post #10

jxy wrote: post #8

This wiki page does not tell you how to setup a jail for the linux OS, so the name is bogus.

Yeah, I'm not sure what the exec.start command would be for systemd-based Ubuntu.

Depends on what you want from the jail. If you want to be able to ssh into it, then make it start ssh ("service ssh start") and that's it.

Re: Ubuntu Linux Jail on FreeBSD 12.2-Release

#77

Post by darthrupert » Tue, Nov 03, 2020, 3:31 PM UTC

nix23 wrote: post #69

darthrupert wrote: post #58

Earlier quoted context omitted.

That’s what systemd is giving the Linux world, though. A carefully designed system for a lot of very essential things, so that distros will need to apply less glue.

>carefully designed system Ehm...really? Are you making fun of us?

In this case, no.

Re: Ubuntu Linux Jail on FreeBSD 12.2-Release

#78

Post by zrm » Tue, Nov 03, 2020, 3:40 PM UTC

Denvercoder9 wrote: post #71

zrm wrote: post #52

Earlier quoted context omitted.

Suppose I want to write my own competitor to systemd-resolvd. I want it to work with systemd-networkd, in the same way as systemd-resolvd does. Or just patch dnsmasq or unbound to be able to do that. Is there a stable interface for that? An RFC I can read? Any guarantee they won't change the interface and break my version, while they update both of theirs together?

Judging from the manpage and a quick look at the code, the only thing for which systemd-networkd and systemd-resolved interact is to get the DNS servers pushed over DHCP, which it does over the D-Bus interface that falls under the interface stability promise[1]. [1] https://systemd.io/PORTABILITY_AND_STABILITY/

That is not the only thing for which they interact, see e.g. systemd.network(5). The systemd-resolved.service itself reads the systemd.network config files. This is what people mean by tightly coupled. But more importantly, you're telling me what it does currently, not what it's going to do tomorrow.

Suppose it did currently only interact through a stable D-Bus interface. What stops them from adding some new interaction and supplementing or replacing the existing one with it? You're left with a guarantee that systemd-resolved will continue to support the old API that systemd-networkd may stop using.

Re: Ubuntu Linux Jail on FreeBSD 12.2-Release

#79

Post by arminiusreturns » Tue, Nov 03, 2020, 4:31 PM UTC

Denvercoder9 wrote: post #73

arminiusreturns wrote: post #51

Earlier quoted context omitted.

Please checkout the progression of Devuan if you are wanting to understand just how viral systemd is in modern linux. If it wasn't so tightly coupled, why did it take 2 years to decouple it? https://sysdfree.wordpress.com/2017/08/16/112/ https://nosystemd.org/

First of all, Devuan wants to get rid of any and all systemd code. This includes for example libsystemd-daemon0, which is a tiny library that implements the stable notification protocol and is a no-op on systems not running systemd. You can reimplement it yourself in pretty much any language, but lots of programs just link against the systemd library because it's easier and has no tangible downside, even for people n…

If you are referring to the lack tight coupling being the ability to remove journald, time sync, etc, then you are correct. I should have been more clear I was talking about systemd as a whole, and not just those other subsystems, but I'll assume you meant the latter, in which case, yeah, it's possible to stop using lots of the systemd subsystems without too much pain (which I have done quite frequently, and found great stability improvements.) To be frank, I just really don't like the handwaiving away of valid criticisms people have (on any topic), with such dismissive language as "People keep saying ... but never supply any proof for that." This to me reeks of intellectual dishonesty, but again, that was my response because I probably misunderstood you to say that about systemd as a whole instead of how you meant it which was focused on gp's comment about subsystems.

One note: many people pretend sysv init has been dead and left behind, but I've seen production systems in major places still using it (not just embedded either). It's not nearly as dead as people might like to think.

Re: Ubuntu Linux Jail on FreeBSD 12.2-Release

#80

Post by yjftsjthsd-h » Tue, Nov 03, 2020, 7:38 PM UTC

mulmen wrote: post #59

yjftsjthsd-h wrote: post #56

Earlier quoted context omitted.

Nobody uses just the kernel alone, so I think it's fair to consider the other required components when looking at the system.

But FreeBSD is an operating system. The userland and kernel are developed together, in the same source tree AFAIK. With Linux you have to glue a user land on to use the kernel, which is a "distribution" which is actually an operating system.

Agreed? I thought we were talking about Linux