systemd init 0 vs poweroff

czezz · 02-06-2019, 07:10 AM

Hi everyone,
before systemd I used to use "init 0" to gracefully shutdown the the system.
Although recently I have heard that in systemd I should not use "init commands" anymore and to shutdown the system gracefully use "poweroff" command.

That is a surprise to me as up to now "poweroff" ment to me cut-off power immediately.
Any comments on that/your opinions & experience ?

michaelk · 02-06-2019, 07:27 AM

Since systemd does not have runlevels init 0 if it works at all would be a shortcut to systemctl command.

poweroff, shutdown and halt are all shortcuts to systemctl and I think that in the old days poweroff actually called shutdown which would be the preferred way.

BW-userx · 02-06-2019, 07:48 AM

I know I just push my power button (laptop here) and it shuts down gracefully, with systemd and systemV, runit (void linux). I do remember seeing/reading in one of them ("scripts") how this was tied to the 'shutdown now' command.

GazL · 02-06-2019, 09:07 AM

Quote:

Originally Posted by BW-userx

I know I just push my power button (laptop here) and it shuts down gracefully, with systemd and systemV, runit (void linux).

That's how I've always done it too.

hazel · 02-06-2019, 10:20 AM

In sysvinit, Poweroff always meant "Shutdown, then switch off via ACPI (soft off)", whereas Halt meant "Shutdown and wait for instructions". I assume systemd uses the same conventions.

If you can get a graceful shutdown by pressing the power button, this must work via ACPI. If you look in /etc/acpi, you should find a script for handling the power button press event. Because it's an ACPI thing, it shouldn't be affected by what kind of init system you have, as long as that system recognises the shutdown command which the script uses.

syg00 · 02-06-2019, 11:03 AM

Things are rarely that cut-and-dried - more true with systemd. FWIW I have always used "poweroff" command; never had an issue.
First place to look for power control options might be "man logind.conf"

GazL · 02-06-2019, 11:06 AM

@hazel, I don't know for certain as I avoid it like the plague, but I wouldn't be surprised to hear that acpid is one of the daemons that systemd has "assimilated".

czezz · 02-07-2019, 06:11 AM

So I understand that nowadays (under systemd based OS) the right way to gracefully shutdown system is:

Code:

# systemctl poweroff

ehartman · 02-07-2019, 11:05 AM

Quote:

Originally Posted by czezz

That is a surprise to me as up to now "poweroff" ment to me cut-off power immediately.

In my system (Slackware) halt, reboot and poweroff are all the same executable and do a "gracefull" shutdown, optionally followed by a poweroff or reboot

Code:

-rwxr-xr-x 1 root root   12312 2013-08-17 05:24:42 halt
lrwxrwxrwx 1 root root       4 2015-10-05 09:09:44 poweroff -> halt
lrwxrwxrwx 1 root root       4 2015-10-05 09:09:44 reboot -> halt

PS: Slackware is still systemd free!

czezz · 02-07-2019, 03:20 PM

Quote:

PS: Slackware is still systemd free!

And hope it will stay this way forever

Under Slack I would keep useing: init 0
However, in systemd OS'es - I understand I must not use init 0 anymore and use: systemctl poweroff

Can anyone confirm that?

michaelk · 02-07-2019, 03:53 PM

Yes, I use shutdown or poweroff which are symlinks to systemctl

scasey · 02-07-2019, 03:59 PM

I haven't switched to the systemd commands yet...I still use init 0 or init 6...but I should. /sbin/init is a link to systemd and could go away in some future release.

BTW the commands are

Code:

shutdown 
or 
poweroff

NOT

Code:

systemctl poweroff

michaelk · 02-07-2019, 04:14 PM

Again since /sbin/shutdown and /sbin/poweroff commands are symlinks to systemctl and both work fine (i.e. poweroff or systemctl poweroff). I use poweroff since its easier to type.

I have not used init 0 command in a very long time and it is symlinked to /lib/systemctl. I just tried it on a CentOS and it still stops the system.