2006/08/25

The Ultimate P2V

There's been a lot of talk about the "Blue Pill" trick where a hypothetical virus would use the new x86 virtualization features (VT or pacifica) to move a running OS under a hypervisor (where the virus would run undetectably) It would be very interesting to extend this into a positive technology...

Imagine a program that uses Blue Pill to move the OS under a hypervisor. That's fine, but the OS is still coupled to the physical devices (network cards, disks, etc). Now have the hypervisor generate a virtual (hotplug) PCI bus and attach it to the running OS. And have it hotplug a vmnic and an emulated scsi controller. The OS notices the new redundant paths to the disks (standard multipathing software) and fails over all the network connections onto the virtual card. Then the hypervisor virtually unplugs the real PCI bus, and we're left with a completely virtualized (i.e. VMotion-able) machine. Without a downtime.

That would be really cool.

This would require:

  • A bluepill-compatible hypervisor that can create virtual hotplug PCI buses, and that can transport running VMs across physical machines
  • An OS that supports PCI hotplug, dynamic disk multipathing, and transparent network failover
  • All the disks on the physical system being on a SAN or otherwise multihosted
--Joe

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