When you sign up, you give me an OpenSSH format public key. I use that to give you ssh access to a simple text-based menu that lets you turn your domain on, off, and allows you to connect to the serial console. (well, in xen, if you want to access pygrub, you need to start the domain and connect to the console at the same time, so there is a 'start the domain up with console' option as well as a 'connect to console' option.)
To login to the console from your own linux box,
ssh -i [secret key] email@example.com
where lsc is your username and tahoe.prgmr.com is your console server.
Once you log in, you see a menu (here, the domain is called lsc) looks a bit like this:
Name ID Mem(MiB) VCPUs State Time(s) lsc 495 255 1 -b---- 1584.9 Options for lsc 1. console 2. create/start 3. shutdown 4. destroy/hard shutdown 5. reboot 6. exit >
if it's not running, you want option 2 (note the unfortunate Xen nominclature. Create means 'start' and 'destroy' means 'hard shutdown' - nothing on this menu does anything directly to your disk image.
In this case, the domain is running (note the 'xm list domain' output at the top) so if this is a new domain, we want option 1, console. Like other serial consoles, often you see nothing until you hit return, at which point you should see the normal login prompt
CentOS release 5.2 (Final) Kernel 2.6.18-53.1.14.el5xen on an i686 lsc login: