xenapi: remove all resources when VM fails to spawn

[Salvatore Orlando]

If a VM fails to spawn, resources such as VDIs, are not removed from the target hypervisor.
This happens when the failure occurs before the VM record is created in xenapi.
vm_ops.destroy is therefore not able to locate all the resources used by the instance of there is no record for that instance in xenapi.

Note: this is different from bug #694935. That bug fix dealt with VM that failed to boot.

[Salvatore Orlando (salvatore-orlando)]

The attached patch keeps track of the resources created on the Xen backend until the VM record is created.

If a failure occurs, the exception handler will destroy all the VDIs created so far, as well as kernel/ramdisk files stored on dom0's filesystem.

[Thierry Carrez (ttx)]

@Salvatore: still working on that ? Or should we unassign you to give someone else a chance to fix it ?

[Salvatore Orlando (salvatore-orlando)]

Branch has been updated to reflect latest changes in xenapi backend.
However, code quality can be improved.
Before proposing for merge, I would like to see if anybody has an opinion on this question: https://answers.launchpad.net/nova/+question/161496

Thanks,
Salvatore