How to start X without a terminal device

[Bud Bundy]

Hi,

I have a headless rendering application.  I'd like to start it in a 
container (LXD in this case, but I had same issue with mesos native 
containerizer) which do not map /dev/ttyX.

Is it possible to start X without a terminal?  I can specify dummy video 
driver, void keyboard/mouse drivers, a virtual/non-existent monitors, 
but I can't seem to figure out a dummy /dev/tty device for X.  Or 
perhaps someone can point to how i could create a dummy virtual terminal.

If it has any bearing, I'm using Ubuntu 16.04, Xorg 1.18.4.  I tried 
this Xdummy xorg.conf configuration: http://xpra.org/xorg.conf.  I was 
starting the server as root to sidestep permission issues if any.  The 
error when running "xinit glewinfo" or even "X :1" was

(EE) parse_vt_settings: Cannot open /dev/tty0 (No such file or directory)

Thank you.