** Summary changed:

- (libvirt) KeyError updating resources for some node, guest.uuid is not in BDM 
list
+ [SRU] (libvirt) KeyError updating resources for some node, guest.uuid is not 
in BDM list

** Description changed:

+ [Impact]
+ 
+ There currently exists a race condition whereby the compute
+ resource_tracker periodic task polls extant instances and checks their
+ BDMs which can occur prior to any mappings having yet been created e.g.
+ root disk mapping for new instances. This patch ensures that instances
+ without any BDMs are skipped.
+ 
+ [Test Case]
+   * deploy Openstack Mitaka with debug logging enabled (not essential but 
helps)
+ 
+   * create an instance
+ 
+   * delete its BDMs - pastebin.ubuntu.com/24287419/
+ 
+   * watch /var/log/nova/nova-compute.log on hypervisor hosting instance
+ and wait for next resource_tracker tick
+ 
+   * ensure that exception mentioned in LP does not occur (happens after
+ "Auditing locally available compute resources for node")
+ 
+ [Regression Potential]
+ 
+ The resource tracker information is used by the scheduler when deciding
+ which compute hosts are able to have an instances scheduled to them. In
+ this case the resource tracker would be skipping instances that would
+ contribute to disk overcommit ratios. As such it is possible that that
+ scheduler will have momentarily skewed information about resource
+ consumption on that compute host until the next resource_tracker tick.
+ Since the likelihood of this race condition occurring is hopefully slim
+ and provided that users have a reasonable frequency for the
+ resource_tracker, the likelihood of this becoming a long term problem is
+ low since the issue will always be corrected by a subsequent tick
+ (although if the compute host in question were saturated that would not
+ be fixed until an instances was deleted or migrated).
+ 
+ --------
+ 
  2016-07-12 09:54:36.021 10056 ERROR nova.compute.manager 
[req-d5d5d486-b488-4429-bbb5-24c9f19ff2c0 - - - - -] Error updating resources 
for node controller.
  2016-07-12 09:54:36.021 10056 ERROR nova.compute.manager Traceback (most 
recent call last):
  2016-07-12 09:54:36.021 10056 ERROR nova.compute.manager   File 
"/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 6726, in 
update_available_resource
  2016-07-12 09:54:36.021 10056 ERROR nova.compute.manager     
rt.update_available_resource(context)
  2016-07-12 09:54:36.021 10056 ERROR nova.compute.manager   File 
"/usr/lib/python2.7/site-packages/nova/compute/resource_tracker.py", line 500, 
in update_available_resource
  2016-07-12 09:54:36.021 10056 ERROR nova.compute.manager     resources = 
self.driver.get_available_resource(self.nodename)
  2016-07-12 09:54:36.021 10056 ERROR nova.compute.manager   File 
"/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 5728, in 
get_available_resource
  2016-07-12 09:54:36.021 10056 ERROR nova.compute.manager     
disk_over_committed = self._get_disk_over_committed_size_total()
  2016-07-12 09:54:36.021 10056 ERROR nova.compute.manager   File 
"/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 7397, in 
_get_disk_over_committed_size_total
  2016-07-12 09:54:36.021 10056 ERROR nova.compute.manager     
local_instances[guest.uuid], bdms[guest.uuid])
  2016-07-12 09:54:36.021 10056 ERROR nova.compute.manager KeyError: 
'0a5c5743-9555-4dfd-b26e-198449ebeee5'
  2016-07-12 09:54:36.021 10056 ERROR nova.compute.manager

** Patch added: "lp1602057-xenial-mitaka.debdiff"
   
https://bugs.launchpad.net/nova/+bug/1602057/+attachment/4851346/+files/lp1602057-xenial-mitaka.debdiff

** Tags added: sts-sponsor

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https://bugs.launchpad.net/bugs/1602057

Title:
  [SRU] (libvirt) KeyError updating resources for some node, guest.uuid
  is not in BDM list

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