[systemd-devel] Synchronization Between Services at Shutdown

[Dan Williams]

On Thu, 2015-04-02 at 16:31 +0200, Martin Pitt wrote:
> Lennart Poettering [2015-04-02 15:31 +0200]:
> > You need to order wpa_supplicant and NM Before=remote-fs-pre.target
> > and pull it it via Wants=remote-fs-pre.target. With that in place
> > during shutdown the mounts will be unmounted first, and NM/wpa only
> > shut down after that.
> 
> wpa_supplicant and NM already have Before=network.target which is even
> stronger. But that doesn't help -- it's D-Bus which we need to leave
> running longer, as dbus going down early tears down all dbus clients as well
> prematurely, thus rendering the above dependencies useless.

At least on the NM side, NM shouldn't be doing anything when dbus-daemon
exits, except logging something and trying to reconnect.  It shouldn't
touch network interfaces except those that require a management daemon,
like wpa_supplicant or Bluetooth or teamd, provided you use the internal
DHCP client.  But ethernet, bridge/bond/vlan/infiniband/etc should be
fine.  Obviously if the supplicant goes down, WiFi goes down, but
running something like NFS over WiFi is kinda asking for trouble, given
that NFS doesn't handle network dropouts well in the first place.

Dan