Comment # 19 on bug 1156501 from Dr. Werner Fink

(In reply to Michal Koutn� from comment #18)
> IIUC, you're missing the a) the socket to session dbus daemon b) the
> enviroment variable telling the path to that socket.
> 
> The a) is realized by dbus.socket of the user systedm instance. For other
> user units b) is done also by dbus.socket. I can't find where is
> DBUS_SESSION_BUS_ADDRESS set for user sessions though (I guess somewhere in
> PAM or by display manager (ancestor of user session processes)).
> 
> Ad a) Is your user systemd instance running? And is dbus.socket active?

On this Tumbleweed I have within the local X11 session

 printenv | grep BUS

DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-ynt2mEliSD,guid=db35f32753f024fe55f960705dcab5a0

whereas on Leap I see

 printenv | grep BUS
 DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/223/bus

well ... now trying ove ssh to Tumbleweed without X11 forward

 printenv | grep DBUS

returns exactly nothing, the same with X11 fowarding.

Using a VNC dispaly on the Tumbleweed and an xterm therein
I see

 printenv | grep DBUS

DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-Q3EYajjIpk,guid=a0fb6beb58aa37222a7682c25dce4d33

but the execution of secret-tool runs into a timeout

 secret-tool lookup imaps gwmail.nue.novell.com
 secret-tool: Error calling StartServiceByName for org.freedesktop.secrets:
Timeout was reached

and indeed there is a user systemd running but only for the local X11 display.
Not for the ssh nor the VNC login.  I'm using for the VNC connection a socjet
and serive unit file where in the serivce unit file the PAMName=login and
User=werner is used.  For ssh connection the /etc/pam.d/sshd includes
common-session which starts with the line

 session optional        pam_systemd.so