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Message #84142
[Bug 1882521] Re: Failing device detachments on Focal
Reviewed: https://review.opendev.org/755799
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=dd1e6d4b0cee465fd89744e306fcd25228b3f7cc
Submitter: Zuul
Branch: master
commit dd1e6d4b0cee465fd89744e306fcd25228b3f7cc
Author: Lee Yarwood <lyarwood@xxxxxxxxxx>
Date: Fri Oct 2 15:11:25 2020 +0100
libvirt: Increase incremental and max sleep time during device detach
Bug #1894804 outlines how DEVICE_DELETED events were often missing from
QEMU on Focal based OpenStack CI hosts as originally seen in bug
#1882521. This has eventually been tracked down to some undefined QEMU
behaviour when a new device_del QMP command is received while another is
still being processed, causing the original attempt to be aborted.
We hit this race in slower OpenStack CI envs as n-cpu rather crudely
retries attempts to detach devices using the RetryDecorator from
oslo.service. The default incremental sleep time currently being tight
enough to ensure QEMU is still processing the first device_del request
on these slower CI hosts when n-cpu asks libvirt to retry the detach,
sending another device_del to QEMU hitting the above behaviour.
Additionally we have also seen the following check being hit when
testing with QEMU >= v5.0.0. This check now rejects overlapping
device_del requests in QEMU rather than aborting the original:
https://github.com/qemu/qemu/commit/cce8944cc9efab47d4bf29cfffb3470371c3541b
This change aims to avoid this situation entirely by raising the default
incremental sleep time between detach requests from 2 seconds to 10,
leaving enough time for the first attempt to complete. The overall
maximum sleep time is also increased from 30 to 60 seconds.
Future work will aim to entirely remove this retry logic with a libvirt
event driven approach, polling for the the
VIR_DOMAIN_EVENT_ID_DEVICE_REMOVED and
VIR_DOMAIN_EVENT_ID_DEVICE_REMOVAL_FAILED events before retrying.
Finally, the cleanup of unused arguments in detach_device_with_retry is
left for a follow up change in order to keep this initial change small
enough to quickly backport.
Closes-Bug: #1882521
Related-Bug: #1894804
Change-Id: Ib9ed7069cef5b73033351f7a78a3fb566753970d
** Changed in: nova
Status: In Progress => Fix Released
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https://bugs.launchpad.net/bugs/1882521
Title:
Failing device detachments on Focal
Status in Cinder:
New
Status in OpenStack Compute (nova):
Fix Released
Bug description:
The following tests are failing consistently when deploying devstack
on Focal in the CI, see https://review.opendev.org/734029 for detailed
logs:
tempest.api.compute.servers.test_server_rescue_negative.ServerRescueNegativeTestJSON.test_rescued_vm_detach_volume
tempest.api.compute.volumes.test_attach_volume.AttachVolumeMultiAttachTest.test_resize_server_with_multiattached_volume
tempest.api.compute.servers.test_server_rescue.ServerStableDeviceRescueTest.test_stable_device_rescue_disk_virtio_with_volume_attached
tearDownClass (tempest.api.compute.servers.test_server_rescue.ServerStableDeviceRescueTest)
Sample extract from nova-compute log:
Jun 08 08:48:24.384559 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: DEBUG oslo.service.loopingcall [-] Exception which is in the suggested list of exceptions occurred while invoking function: nova.virt.libvirt.guest.Guest.detach_device_with_retry.<locals>._do_wait_and_retry_detach. {{(pid=82495) _func /usr/local/lib/python3.8/dist-packages/oslo_service/loopingcall.py:410}}
Jun 08 08:48:24.384862 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: DEBUG oslo.service.loopingcall [-] Cannot retry nova.virt.libvirt.guest.Guest.detach_device_with_retry.<locals>._do_wait_and_retry_detach upon suggested exception since retry count (7) reached max retry count (7). {{(pid=82495) _func /usr/local/lib/python3.8/dist-packages/oslo_service/loopingcall.py:416}}
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall [-] Dynamic interval looping call 'oslo_service.loopingcall.RetryDecorator.__call__.<locals>._func' failed: nova.exception.DeviceDetachFailed: Device detach failed for vdb: Unable to detach the device from the live config.
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall Traceback (most recent call last):
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall File "/usr/local/lib/python3.8/dist-packages/oslo_service/loopingcall.py", line 150, in _run_loop
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall result = func(*self.args, **self.kw)
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall File "/usr/local/lib/python3.8/dist-packages/oslo_service/loopingcall.py", line 428, in _func
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall return self._sleep_time
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall File "/usr/local/lib/python3.8/dist-packages/oslo_utils/excutils.py", line 220, in __exit__
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall self.force_reraise()
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall File "/usr/local/lib/python3.8/dist-packages/oslo_utils/excutils.py", line 196, in force_reraise
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall six.reraise(self.type_, self.value, self.tb)
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall File "/usr/local/lib/python3.8/dist-packages/six.py", line 703, in reraise
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall raise value
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall File "/usr/local/lib/python3.8/dist-packages/oslo_service/loopingcall.py", line 407, in _func
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall result = f(*args, **kwargs)
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall File "/opt/stack/nova/nova/virt/libvirt/guest.py", line 453, in _do_wait_and_retry_detach
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall raise exception.DeviceDetachFailed(
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall nova.exception.DeviceDetachFailed: Device detach failed for vdb: Unable to detach the device from the live config.
Jun 08 08:48:24.388855 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: ERROR oslo.service.loopingcall
Jun 08 08:48:24.390684 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: WARNING nova.virt.block_device [None req-8af75b5f-2587-4ce7-9523-d2902eb45a38 tempest-ServerRescueNegativeTestJSON-1578800383 tempest-ServerRescueNegativeTestJSON-1578800383] [instance: 76f86b1f-8b11-44e6-b718-eda3e7e18937] Guest refused to detach volume 6b0cac03-d6d4-48ae-bf56-06de389c0869: nova.exception.DeviceDetachFailed: Device detach failed for vdb: Unable to detach the device from the live config.
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