Start Xserver without Monitors

[weaponfire]

Dear all:
I'm working on a cluster server, and there are no monitors attached to nodes of the cluster. Each node of the cluster equipped with two Nvidia video cards, and I want to start a xserver for each node to create a OpenGL context for 3D off-screen rendering. but the "xinit" was failed because monitors are needed.
Is there a solution to setup a virtual monitor or something for each video card so the OpenGL context could be created?
many thanks for your help

[Rubberman]

Have you installed the framebuffer interface? You don't need a monitor, but you do need a framebuffer.

[weaponfire]

Have you installed the framebuffer interface? You don't need a monitor, but you do need a framebuffer.

Thanks but I'm a newer for linux, would you tell me how to install framebuffer interface? and what do I need to do? thanks a lot

[Rubberman]

Actually, you only need an X server running on your client, and the X libraries installed on the server machines. Then you can easily run an Xterm via an SSH connection (with X tunneling enabled) on each, displaying them on your client. That's what I would do. Alternatively, you can install the framebuffer package (called directfb and found in the epel repositories on Red Hat distributions) on the server and the VNC package on the servers as well as your client. Then you configure VNC to connect to a virtual console on each server, which would in effect be an X login session with local display on your client.

As you might see, the first option, just running an X application on the server via SSH with it's window output back on your client is probably a lot simpler. I have used both approaches in the past, and prefer to use the SSH tunneling one as it has much less impact on the health of the servers, not to mention that it is a lot simpler to configure.