nova-compute can't perform any actions during waiting response from Ceph

[Leontii Istomin]

In case when Ceph performance is slow, nova-compute can't even poll status to nova-api.

Here we can see that nova-compute tried to resize disk and hanged on connection to Ceph backend. During the time nova-compute didn't report about its status:
http://paste.openstack.org/show/412683/

api: '1.0'
astute_sha: 34e0493afa22999c4a07d3198ceb945116ab7932
auth_required: true
build_id: 2015-07-27_09-24-22
build_number: '98'
feature_groups:
- mirantis
fuel-agent_sha: 2a65f11c10b0aeb5184247635a19740fc3edde21
fuel-library_sha: 39c3162ee2e2ff6e3af82f703998f95ff4cc2b7a
fuel-ostf_sha: 94a483c8aba639be3b96616c1396ef290dcc00cd
fuelmain_sha: 921918a3bd3d278431f35ad917989e46b0c24100
nailgun_sha: d5c19f6afc66b5efe3c61ecb49025c1002ccbdc6
openstack_version: 2015.1.0-7.0
production: docker
python-fuelclient_sha: 58c411d87a7eaf0fd6892eae2b5cb1eff4190c98
release: '7.0'

[Leontii Istomin (listomin)]

Way to solve the issue from Roman Podoliaka: http://paste.openstack.org/show/412686/

[Fuel Devops McRobotson (fuel-devops-robot)]

Fix proposed to branch: openstack-ci/fuel-7.0/2015.1.0
Change author: Roman Podoliaka <email address hidden>
Review: https://review.fuel-infra.org/10379

[Dina Belova (dbelova)]

Roman, if the fix will be included to 7.0, please update the bug status for 7.0.x

[Roman Podoliaka (rpodolyaka)]

We no longer fixing medium bugs in 7.0, moving to 8.0

[Fuel Devops McRobotson (fuel-devops-robot)]

Change abandoned by Roman Podoliaka <email address hidden> on branch: openstack-ci/fuel-7.0/2015.1.0
Review: https://review.fuel-infra.org/10379

[Roman Podoliaka (rpodolyaka)]

All calls to rados lib are done in threads - https://github.com/ceph/ceph/blob/master/src/pybind/rados.py#L202-L235 - and *should not* block a python eventlet process.

Marking this as Incomplete. Let's see if we can reproduce this ever again (I believe, we haven't seen this in 8.0).

[Roman Podoliaka (rpodolyaka)]

No new repros and #6 summaries why this must not be a problem anymore.