I have a bit of a problem with Xen. Each time I try to run xm create I get the following error:
dom0:~# xm create -c staros.xm
Using config file "./staros.xm". Started domain StarOS-3 xenconsole: Could not read tty from store: No such file or directory
Is this familiar to anyone?
I believe my config is in order. At first I suspected the path to qemu-dm wasn't set correctly.
The error you are describing could mean two things:
It is documenting a well known race in xenstore
The psuedo TTY needed to attach to a domain's console is stored in xenstore in several places. The Xen console client establishes an inotify style watch on that value, so that it can reconnect to the console if the backing file descriptor happens to change. However, takes a few seconds for that information to be populated in xenstore from the time that the domain is initially created.
If you post the output of xm info, it would be easy to see if you are dealing with a well known race.
The backing psuedo terminal can't be created
Common reasons for this would be /dev/pts not being mounted. If you run xenstore-ls /local/domain/{domain_id} after starting the domain without the -c option, you will see the contents of the store for that domain. Look for the line (near the bottom) that says
tty="/dev/pts/{pty}"
Verify that the pty does, in fact, exist.
The xen console daemon uses two actual file descriptors to make it happen. The first is a psuedo file descriptor (obtained via xs_fileno()) on that specific piece of information in the node, so it can poll() to see if that information changes. The second is a real FD returned from open() (yes, O_NONBLOCK is passed) which actually reads/writes to the psuedo tty.
It looks like it's not even finding the psuedo FD from xenstore, which means the backing pty is likely existentially challenged.
