From: fungal-net <fungalnet@obarun.org>
To: supervision@list.skarnet.org
Subject: Re: interesting claims
Date: Fri, 17 May 2019 11:21:00 +0000 [thread overview]
Message-ID: <5f5b6035-240b-e6d6-497d-d9bb945d135f@obarun.org> (raw)
In-Reply-To: <em557be3bb-11b8-4983-9c51-af19675020e8@elzian>
Laurent Bercot:
> I'm not sure I understand your question, but I think there are
> really two different questions here; I'll try to reformulate them,
> correct me if I'm wrong.
>
> 1. Is booting a system a linear process where every step is
> reversible?
Well, assuming it wasn't from experience I was asking if it could
possibly be reversible. The answer did help me understand that what may
be theoretically possible it is most likely unnecessary, like having
very busy one-way streets around a building block and a parking space
became available 5 car lengths behind you. It may be quicker to go
around the block (big fat luck).
> 2. Is it possible to restart a system "from scratch" without
> rebooting?
>
> The answer to both questions is "not really, but it doesn't matter".
>
>. . . .
>. . . . .
>
> Stage 1 isn't reversible; once it's done, you never touch it again,
> you don't need to "reverse" it. It would be akin to also unloading
> the kernel from memory before shutting down - it's just not necessary.
But if you can unload it you can reload it or load a different one?
> . . . . .
> . . . .
>
> - If you want to kill every process but pid 1 and have the system
> reconstruct itself from there, then yes, it is possible, and that is
> the whole point of having a supervision tree rooted in pid 1. When
> you kill every process, the supervision tree respawns, so you always
> have a certain set of services running, and the system can always
> recover from whatever you throw at it. Try it: grab a machine with
> a supervision tree and a root shell, run "kill -9 -1", see what
> happens.
Very interesting:
Runit: I've never seen anything poweroff so fast (void faster than artix)
OpenRC: Nice,
init
|_ zsh
when I exited the shell there was nothing but a dead cursor on my screen
S6/66: Goodmorning, it is like I had rebooted and was looking at my login:
sysV: init and 6 ttys with shell ... nothing can kill it that I know off.
sys.239.D: I hate to say, same behavior as s6/66
***BSD: I must research to find the equivalent to kill -9 -1 but it
seemed like openrc behavior.
>
> --
> Laurent
>
>
next prev parent reply other threads:[~2019-05-17 11:21 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-29 19:19 Jeff
2019-04-30 2:49 ` Guillermo
2019-04-30 8:22 ` Laurent Bercot
2019-05-03 0:53 ` what init systems do you use ? Jeff
2019-05-11 18:45 ` Guillermo
2019-05-13 19:13 ` multiplexd
2019-05-13 20:36 ` Laurent Bercot
2019-05-13 21:09 ` Steve Litt
2019-05-14 2:34 ` Guillermo
2019-05-13 21:16 ` Joshua Ismael Haase Hernández
2019-05-14 5:50 ` Colin Booth
2019-05-14 7:15 ` eric vidal
2019-04-30 8:47 ` interesting claims Jonathan de Boyne Pollard
2019-05-01 7:26 ` Steve Litt
2019-05-01 7:33 ` Steve Litt
2019-05-01 18:13 ` Laurent Bercot
2019-05-15 17:22 ` Steve Litt
2019-05-15 23:22 ` Oliver Schad
2019-05-16 1:07 ` Steve Litt
2019-05-16 5:36 ` fungal-net
2019-05-16 8:32 ` Laurent Bercot
2019-05-16 17:10 ` Jeff
2019-05-17 0:23 ` Dewayne Geraghty
2019-05-17 11:21 ` fungal-net [this message]
2019-05-17 22:57 ` Guillermo
2019-05-18 0:52 ` Jeff
2019-05-18 16:26 ` fungal-net
2019-05-18 20:04 ` Guillermo
2019-05-19 11:24 ` fungal-net
2019-05-19 12:57 ` killall test run Jeff
2019-05-19 17:29 ` Colin Booth
2019-05-19 20:39 ` Guillermo
2019-05-19 23:06 ` Laurent Bercot
2019-05-19 20:35 ` interesting claims Guillermo
2019-05-03 1:37 ` how to handle system shutdown ? Jeff
2019-05-03 19:25 ` Laurent Bercot
2019-05-05 0:52 ` is it required to call kill() from process #1 ? Jeff
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