[systemd-devel] killmode

[Mike Gilbert]

On Fri, May 20, 2022 at 12:54 PM Pascal <patatetom at gmail.com> wrote:
>
> not really in the sense that qemu-nbd launches and immediately gives the hand back to the script that called it.
> the script ends positively and qemu-nbd is killed by systemd because it is considered to be garbage left behind by the script.
> this is not quite the case of a timeout that systemd terminates, but the result is the same.
> in this case, qemu-nbd looks more like a daemon.
>
> I was wondering if there was a way to propagate the killmode through a udev rule that starts a script (like a service)... but it seems from the documentation that the answer is no :-(
>
> """In order to activate long-running processes from udev rules, provide a service unit and pull it in from a udev device using the SYSTEMD_WANTS device property. See systemd.device(5) for details."""
> I would appreciate (and maybe I won't be the only one) a concrete example based, for example,  on my problem ;-)
>
> let's just say that my rule is :
>
> KERNEL=="sdb", RUN+="/usr/local/sbin/myscript"
>
> and my script is :
>
> #!/usr/bin/bash
> qemu-nbd -r -s -f raw -c /dev/nbd0 /dev/sdb

The most direct translation would be something like this:

qemu-nbd0-sdb.service:
[Service]
ExecStart=qemu-nbd -r -s -f raw -c /dev/nbd0 /dev/sdb

udev rule:
KERNEL=="sdb", ENV{SYSTEMD_WANTS}+="qemu-nbd0-sdb.service"