[dm-devel] [PATCH] multipathd.service: add dependency on systemd-udevd-kernel.socket

[Benjamin Marzinski]

On Thu, Dec 02, 2021 at 11:48:12AM +0100, mwilck at suse.com wrote:
> From: Martin Wilck <mwilck at suse.com>
> 
> Since f42d918 ("multipathd: Remove dependency on
> systemd-udev-settle.service"), multipathd has no dependencies on
> udev any more. In reality, multipathd depends quite heavily on udev.
> 
> multipathd startup succeeds indeed if udevd isn't running. Connecting to the
> udev monitor netlink socket works, too, and if udevd is started later on,
> multipathd will receive events over this socket. multipathd doesn't connect to
> the udev control socket, but it does attempt to trigger uevents using
> sysfs. For these events to be processed, the udev kernel socket must be
> listening. For that, it's sufficient to depend on systemd-udevd-kernel.socket,
> which will start udevd on demand if it isn't running.
> 
> Signed-off-by: Martin Wilck <mwilck at suse.com>
Reviewed-by: Benjamin Marzinski <bmarzins at redhat.com>
> 
> ---
> Note: I'd like to get this merged into the current upstream PR.
> ---
>  multipathd/multipathd.service | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/multipathd/multipathd.service b/multipathd/multipathd.service
> index 87cb534..1919b38 100644
> --- a/multipathd/multipathd.service
> +++ b/multipathd/multipathd.service
> @@ -2,6 +2,8 @@
>  Description=Device-Mapper Multipath Device Controller
>  Before=iscsi.service iscsid.service lvm2-activation-early.service
>  Before=local-fs-pre.target blk-availability.service shutdown.target
> +Wants=systemd-udevd-kernel.socket
> +After=systemd-udevd-kernel.socket
>  After=multipathd.socket systemd-remount-fs.service
>  DefaultDependencies=no
>  Conflicts=shutdown.target
> -- 
> 2.34.0