Ask for step-by-step instructions to connect between local X server and remote display manager via XDMCP

[Christopher Barry]

On Tue, 30 Dec 2014 21:05:18 -0500
Heng Zhou <hzhou1 at cs.uml.edu> wrote:

>I want set up an environment in which a local X server is connecting a
>remote display manager via XDMCP protocol, just like the second
>picture in the wikipedia item "X display manager" (
>http://en.wikipedia.org/wiki/X_display_manager_%28program_type%29)
>shows. The specific configuration is described in the following.
>
>A computer is running ubuntu 14.04 LTS in front of me. Call it "local
>machine".
>
>A headless server is running ubuntu 14.04 LTS at another geographical
>place. Call it "remote machine". The remote machine has no graphics
>card, no attached monitor, but I have full control over it.
>Concretely, it is an Amazon EC2 ubuntu instance.
>
>The local machine has a physical graphics card and an attached
>monitor. It is running ordinary ubuntu desktop so the X Window System
>-- X.Org Server -- is running after boot, presumably.
>
>The remote machines has installed LightDM, the display manager of
>ubuntu. And I am sure it is running over there by checking the results
>returned by command ps aux|grep lightdm.
>
>That's the configuration of the local and remote machines. Now I need
>to follow the steps in the wikipedia item "X display manager" (please
>see the link above) to try to connect the local X server with the
>remote display manager LightDM. What I wish to happen should be,
>according to my understanding of the wikipedia webpage, as follows:
>
>(1) The local machines run a XDMCP Chooser program to select the
>display manager running now on the remote machine to connect.
>
>(2) The X server on the local machine uses XDMCP protocol to shake
>hands with the remote display manager LightDM.
>
>(3) The remote display manager LightDM should respond as expected:
>
>a) it connects to the local X server as a client
>
>b) display a login GUI on the local machine, with the assistance of the
>local X server
>
>c) start an X session after I log in
>
>d) run X applications like xterm in the session as directed; display
>its graphical output on the local machine, using the local X display
>server.
>
>e) If possible, I hope in addition to show the unity desktop on the
>local machine, just like a normal ubuntu desktop, but the executable
>code is actually running on the remote machine.
>
>That's all I want. But I have no idea how all these can be done. I
>searched the internet and found something like
>http://wiki.ubuntu.com/xdmcp and
>http://danilodellaquila.com/blog/how-to-remote-login-via-xdmcp-in-ubuntu,
>but they are either too old or too too old, and therefore useless for
>my configuration. So I wonder if anyone familiar with XDMCP and having
>a workable experience could please share his/her ideas on how to
>setting up this environment. Please be specific. Thanks a lot. If you
>need any other info, please ask.
>
>PS: The display manager on the remote machine doesn't have to be
>LightDM. I specifies it just because it's light weight and I'm
>familiar with ubuntu desktop. You can use other option, say, GDM, if
>you are working or once worked with it, to set up the environment.
>
>Looking forward to any workable instructions. Thanks.


See: http://ltsp.org/

--
-C