After upgrading from Rocky to Stein, nova-compute services fail to start
new instances with the following error message:
Failed to allocate the network(s), not rescheduling.
Looking in the nova-compute logs, we also see this:
Neutron Reported failure on event
network-vif-plugged-60c05a0d-8758-44c9-81e4-754551567be5 for instance
32c493c4-d88c-4f14-98db-c7af64bf3324: NovaException: In shutdown, no new
events can be scheduled
During the upgrade process, we send nova containers a SIGHUP to cause
them to reload their object version state. Speaking to the nova team in
IRC, there is a known issue with this, caused by oslo.service performing
a full shutdown in response to a SIGHUP, which breaks nova-compute.
There is a patch [1] in review to address this.
The workaround employed here is to restart the nova compute service.
[1] https://review.openstack.org/#/c/641907
Change-Id: Ia4fcc558a3f62ced2d629d7a22d0bc1eb6b879f1
Closes-Bug: #1821362
192dcd1e1b