Xen or KVM VPS "rescue" best practices?
Let's suppose I have upgraded a kernel in my VPS, and there is a problem with the new kernel, so that the OS no longer boots. What are my options to recover at this point. With the two Xen providers I used so far, the only option seemed to be "File a ticket and ask them to change back Default=value in /boot/grub/grub.conf for you". Does pyGrub even show any sort of a kernel selection menu to Serial Console? I don't think it does.
So are there any providers with support for booting your VPS into a rescue ISO? I know some KVM providers had that (which ones?), but what about Xen?