For those “oh poop” moments
I was in a situation where I had a running Xen guest, but the config file that defined the DomU was missing.
Fortunately, the listing command (
xl list) has a long option,
xl list -l, which prints out domain information in JSON format. This includes config information, from which the DomU configuration can be rebuilt.
Update: I hit a snag three months later when the config of one of the DomU’s wasn’t quite right, resulting in an “Unable to find partition containing kernel” error, but that was fixable