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

[Thorsten Kukuk]

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.

 Thanks,
    Thorsten

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)