Cloned from launchpad blueprint https://blueprints.launchpad.net/nova/+spec/xen-support-for-hypervisor-versions.

Description:

Ensure that the image lands on a hypervisor version that is equal or newer to the Xen tools version. This is to prevent an instance with newer tools from landing on an older host.
approach:
add xenapi tools version to image metadata, which would be copied over to the instance as well
advertise the prominent XS version within a cell to the parent through capabilities
add a cell-scheduler-filter to filter cells with compatible xen version hosts

Specification URL (additional information):

None