LightDM exits immediately on NBD root

[Dachnaz]

Hi folks,

I've been struggling with getting LightDM to start consistently on my diskless nodes. The problem only happens when the root is mounted over NBD; I can mount the NBD image as a loop device on the server, export the mountpoint over NFS and boot with an NFS root and it works fine. The NBD server does allow for copy-on-write and this functionality works fine. Using a command like # startx brings up the X server with full functionality. The logs don't have a whole lot of interesting messages, but there's got to be something - maybe someone here has an idea. Pertinent logs are seen at http://bpaste.net/show/422671/ .

Thanks in advance!

Dachnaz

EDIT: Here's (http://bpaste.net/show/422771/ ) what a successful LightDM startup looks like. I got these logs from mounting the NBD as loopback, exporting the mount and mounting the root with NFS. I notice that the first divergence in lightdm.log is at line 53 in the pasted file: the failed instance catches signal 15 from the LightDM process itself, while the successful instance terminates a session. Ok, so why did the LightDM process SIGTERM iteself?