The Book of Xen

Use of the XenStore for Fun and Profit

The XenStore is the configuration database in which Xen stores information on the running domUs. Although Xen uses the XenStore internally for vital matters like setting up virtual devices, you can also write arbitrary data to it from domUs as well as from dom0. Think of it as some sort of interdomain socket.

This opens up all sorts of possibilities. For example, domains could, in theory, negotiate among themselves for access to shared resources. Or you could have something like the talk system on the shared UNIX machines of yore—multiuser chat between people running on the same host. You could use it to propagate host-specific messages, for example, warning people of impending backups or migration. For the ...