** Description changed: * SRU DESCRIPTION BELOW * Nova has a race condition between resize_instance() compute manager call and the update_available_resources periodic job. If they overlap at the right place, when resize_instance calls finish_resize, then periodic job will not track the migration nor the instance on the source host. It causes that the PCPU allocation on the source host is dropped in the resource tracker (not in placement). Then when the resize is confirmed nova tries to free the pinned cpus again on the source host and fails with CPUUnpinningInvalid as they are already freed. I've pushed a reproduction test: https://review.opendev.org/c/openstack/nova/+/810763 It is reproducible at least on master, xena, wallaby, and victoria =============== SRU DESCRIPTION =============== [Impact] Due to a race condition the tracking of pinned CPU resources can go off- sync causing "No valid host" errors while being unable to create new instances with CPU pinning, as the previous pinned CPUs were not marked as freed. Part of the reason is addressed in the fix for LP#1953359 where a migration context is not pointing to the proper node during the race condition window, resulting in a CPUPinningInvalid error. This fix complements LP#1953359 by addressing the improper tracking of resources that happens only when the resource tracker periodic job runs in the source node while the flavor registered corresponds to the one of the destination. That is solved by setting the instance.old_flavor so the CPU pinning resources are tracked properly. [Test case] The test case for this was already implemented on non-live functional tests upstream: in nova/tests/functional/libvirt/test_numa_servers.py: - test_resize_dedicated_policy_race_on_dest_bug_1953359 - test_resize_confirm_bug_1944759 - test_resize_revert_bug_1944759 As this is a race condition it is very difficult to validate, even upstream, so the functional tests mock certain parts of the code to simulate the entire scope of the workflow. It is a non-live functional test, so it is more akin to a broader unit test. + The test case that will be run for this SRU is running the charmed- + openstack-tester [1] against the environment containing the upgraded + package (essentially as it would be in a point release SRU) and expect + the test to pass. Test run evidence will be attached to LP. + [Regression Potential] The code is considered stable today in newer releases and the scope of the code affected is fairly limited. Given that it is a race condition that it is difficult to validate, despite the non-live functional tests, the regression potential is moderate. [Other Info] None. + + [1] https://github.com/openstack-charmers/charmed-openstack-tester
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1944759 Title: [SRU] confirm resize fails with CPUUnpinningInvalid To manage notifications about this bug go to: https://bugs.launchpad.net/cloud-archive/+bug/1944759/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
