yahoo-eng-team team mailing list archive

[Thierry Carrez <thierry.carrez+lp@xxxxxxxxx>]

** Changed in: nova
       Status: Fix Committed => Fix Released

-- 
You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to OpenStack Compute (nova).
https://bugs.launchpad.net/bugs/1240542

Title:
  libvirt: the None value for the 'os_type' property is passed to glance
  when doing a snapshot

Status in OpenStack Compute (Nova):
  Fix Released

Bug description:
  This change: https://review.openstack.org/42877 introduced the ability
  to pass os_type property to glance when we are doing a snapshot, but
  the change doesn't manage correctly the None value for this property.

  The result of that is that we have a porperty called 'os_type': None associated with the snapshotted image.
  That is a problem as this property is used when we create the backing file for the ephemeral disks.

  From nova/virt/libvirt/driver/py:
   # Lookup the filesystem type if required
   os_type_with_default = instance['os_type']
   if not os_type_with_default:
       os_type_with_default = 'default'

  and then we create the ephemeral file name using this rule:

  fname = "ephemeral_%s_%s" % (ephemeral_gb, os_type_with_default)

  Now consider an instance with a flavor with an ephemeral disk of 50 G and without the os_type defined, the resulting backing file will be:
  "ephemeral_50_default"
  At this point if we create a snapshot from that instance and we boot from it we will have another backing file created and called:
  "ephemeral_50_None"

  That is bad for at least two reasons:
  1 performance issue: we need to create a new backing file which is not actually necessary
  2 resources leaking: those backing files consume disk capacity on the host

To manage notifications about this bug go to:
https://bugs.launchpad.net/nova/+bug/1240542/+subscriptions