Comment 1 for bug 1882521

There are also some warnings like this

Jun 08 08:37:13.280300 ubuntu-focal-rax-dfw-0017012548 nova-compute[82495]: DEBUG oslo_concurrency.processutils [None req-bc4635cd-81f9-435d-b60b-fdd64dffa958 None None] Running cmd (subprocess): /usr/bin/python3 -m oslo_concurrency.prlimit --as=1073741824 --cpu=30 -- env LC_ALL=C LANG=C qemu-img info /opt/stack/data/nova/instances/001ba6d1-94e8-4108-9b2c-5ee92df425b9/disk --force-share --output=json {{(pid=82495) execute /usr/local/lib/python3.8/dist-packages/oslo_concurrency/processutils.py:371}}
Jun 08 08:37:13.288934 ubuntu-focal-rax-dfw-0017012548 nova-compute[91401]: Exception ignored in: <function _after_fork at 0x7f0fb37e3b80>
Jun 08 08:37:13.288934 ubuntu-focal-rax-dfw-0017012548 nova-compute[91401]: Traceback (most recent call last):
Jun 08 08:37:13.288934 ubuntu-focal-rax-dfw-0017012548 nova-compute[91401]: File "/usr/lib/python3.8/threading.py", line 1454, in _after_fork
Jun 08 08:37:13.288934 ubuntu-focal-rax-dfw-0017012548 nova-compute[91401]: assert len(_active) == 1
Jun 08 08:37:13.288934 ubuntu-focal-rax-dfw-0017012548 nova-compute[91401]: AssertionError:

but I'm not sure whether they might be related, something different, or just purely cosmetical. They also appear for other services like c-vol, so not nova-specific. See also https://bugs.launchpad.net/bugs/1863021