It seems that profile.d is used in some distros that use some shells that parse that folder for application specifics setups.

In my devuan installation:

/etc/profile.d$ ls
bash_completion.sh       flatpak.sh  gawk.sh      vte.csh  gawk.csh    vte-2.91.sh

But that wont work in a case like mine but only if libvirtd was reading some shell enviroment
variable to determine what net setup to enable when started.

So i guess profile.d is one way to setup an 'enviroment' for applications that would look to certain env variables.
If an app looks only to a config file profile.d it's not needed.

In my case i found first here  about a command that fixes
a network error in virt-manager. Now as @xinomilo told me that can be set either with a terminal command or a gui setting   that changes a relative setting.

I propably was unlucky finding only the first 'solution'  that make me understand that a command fixes an error . But now it seems it's just an application
setting that propably sitting in a config file and there are two ways to change that 'file' and propably to edit it by a text editor.
And maybe virt-manager shouldnt either report it as an error! That small detail could have put me into a different fix mentality and not in the 'config' mentality.

To sum it up. It was a setting issue masqueraded as a  pseudo 'correct functioning' issue.

chomwitt wrote:

From where ? From general options or a VM options ? I didnt find anything.

Connection Options.
if you already connected virt-manager to local libvirtd : choose that (qemu:///system) connection and :
(menu) Edit -> Connection Details -> Virtual Networks tab -> choose network, and check "Autostart On Boot"  on network Details.

I found it. Thanks!

From where ? From general options or a VM options ? I didnt find anything.

Connection Options.
if you already connected virt-manager to local libvirtd : choose that (qemu:///system) connection and :
(menu) Edit -> Connection Details -> Virtual Networks tab -> choose network, and check "Autostart On Boot"  on network Details.

.. (you can also change this from virt-manager/GUI).

From where ? From general options or a VM options ? I didnt find anything.

Head_on_a_Stick wrote:

Was the script executable?

Sorry, that was a stupid question. Files in /etc/profile.d/ are sourced rather than executed. D'oh!

That explains why other scripts in profile.d werent executable.

Generaly i realized that profile.d is for preparing the system wide enviroment (of bash only or more generally ?)
So a more sound approach would be to start libvirtd and then make sure the default networking is enabled .

Was the script executable?

Sorry, that was a stupid question. Files in /etc/profile.d/ are sourced rather than executed. D'oh!

virsh is a libvirt client, so yes, libvirtd must be started in order for virsh to work..
although this https://dev1galaxy.org/viewtopic.php?pid=36441#p36441 makes your command unnecessary.. (you can also change this from virt-manager/GUI).

Yes i understand that. But i was curious to see if indeed a 'root' command can be executed in profile.d
So i could make the script wait and poll the processes and when libvirt is executed then to execute the command!

The test var is changed but not the net default state.
I suspect that virt-manager and libvirtd process must have started first.

Have you tried

# virsh net-autostart default

^ I think that should enable it to auto start without having to run your command.

Reference: https://libvirt.org/sources/virshcmdref … start.html

Are you familiar with cron jobs? That's one way to do it.

I know it's purpose, not familiar but i'll manage.

I tried that so far:

$ less /etc/profile.d/enableqemunetworking.sh
#!/bin/sh
virsh net-start default   &

but didnt work..
@HeadonStick i try to enable qemu networking but the command only works with sudo.

I want to run a 'sudo' command at login.

Why do you want to do that? What are you trying to achieve?

See also https://xyproblem.info/