[systemd-devel] RootImage and tmpfs on /run not always there

[Luca Boccassi]

On Mon, 2 Sept 2024 at 15:00, Thorsten Kukuk <kukuk at suse.com> wrote:
>
> Hi,
>
> after some more testing: the problem is the "+" prefix of
> ExecStartPre, this does not work together with RootImage. Is this
> supposed to work? Even if I cannot really imagine a valid use case for
> this, except enhancing existing service files instead of rewriting
> them for images.

Hi,

That's expected, see table at:

https://www.freedesktop.org/software/systemd/man/latest/systemd.service.html#Command%20lines

> On Tue, Aug 27, 2024 at 12:38 PM Thorsten Kukuk <kukuk at suse.com> wrote:
> >
> > Hi,
> >
> > When playing with soft-reboot and services running from a root image
> > (in this case btrfs subvolume), I run into something which looks like
> > a bug for me.
> > So the service files have:
> > RootImage=/dev/vda2
> > RootImageOptions=ro,subvolid=278
> >
> > If a service file has any of the following three keywords in the
> > service section (this example is from bind):
> > Type=forking
> > KillMode=process
> > ExecStartPre=+/usr/libexec/bind/named.prep
> >
> > Then /run will not be created with tmpfs. If I remove all three
> > keywords, /run will be created with tmpfs.
> >
> > Is there a special logic behind this? Or just a bug?
> >
> > With all other services I tested until now, I have in the logs:
> > Aug 27 08:11:07 microos (rsyncd)[1452]: Applying namespace mount on
> > /run/systemd/mount-rootfs/run
> > Aug 27 08:11:07 microos (rsyncd)[1452]: Mounting tmpfs (tmpfs) on
> > /run/systemd/mount-rootfs/run (0 "")...
> >
> > and it is working.  But this two lines are missing with bind and all
> > following operations will fail:
> > Aug 27 10:25:11 microos (med.prep)[2442]: Applying namespace mount on
> > /run/systemd/mount-rootfs/run/dbus/system_bus_socket
> > Aug 27 10:25:11 microos (med.prep)[2442]: Followed source symlinks
> > /run/dbus/system_bus_socket → /run/dbus/system_bus_socket.
> > Aug 27 10:25:11 microos (med.prep)[2442]: Bind-mounting
> > /run/dbus/system_bus_socket on
> > /run/systemd/mount-rootfs/run/dbus/system_bus_socket (MS_BIND|MS_REC
> > "")...
> > Aug 27 10:25:11 microos (med.prep)[2442]: Failed to mount
> > /run/dbus/system_bus_socket (type n/a) on
> > /run/systemd/mount-rootfs/run/dbus/system_bus_socket (MS_BIND|MS_REC
> > ""): No such file or directory
> > Aug 27 10:25:11 microos (med.prep)[2442]: Failed to create destination
> > mount point node
> > '/run/systemd/mount-rootfs/run/dbus/system_bus_socket', ignoring: No
> > such file or directory
> > Aug 27 10:25:11 microos (med.prep)[2442]: Failed to mount
> > /run/dbus/system_bus_socket to
> > /run/systemd/mount-rootfs/run/dbus/system_bus_socket: No such file or
> > directory
> > Aug 27 10:25:11 microos (med.prep)[2442]: bind.service: Failed to set
> > up mount namespacing: /run/dbus/system_bus_socket: No such file or
> > directory
> >
> >  Thanks,
> >    Thorsten
> >
> > --
> > Thorsten Kukuk, Distinguished Engineer, Senior Architect, Future Technologies
> > SUSE Software Solutions Germany GmbH, Frankenstraße 146, 90461
> > Nuernberg, Germany
> > Managing Director: Ivo Totev, Andrew McDonald, Werner Knoblich (HRB
> > 36809, AG Nürnberg)
>
>
>
> --
> Thorsten Kukuk, Distinguished Engineer, Senior Architect, Future Technologies
> SUSE Software Solutions Germany GmbH, Frankenstraße 146, 90461
> Nuernberg, Germany
> Managing Director: Ivo Totev, Andrew McDonald, Werner Knoblich (HRB
> 36809, AG Nürnberg)