Charm doesn't allow setting cpu-shared-set and cpu-dedicated-set without vcpu_pin_set set

[Nikolay Vinogradov]

I'm deploying OpenStack Ussuri on Bionic using the charm cs:nova-compute-kvm-320 with Juju 2.8.3 and MAAS 2.8.1.

In my bundle.yaml vcpu-pin-set option was not set for nova-compute-kvm charm. I had all-green Juju deployment when I attempted to set Nova's cpu_shared_set and cpu_dedicated_set using corresponding charm options cpu-shared-set and cpu-dedicated-set:

$ juju config nova-compute-kvm-critical -m openstack cpu-shared-set="8-23"
$ juju config nova-compute-kvm -m openstack cpu-dedicated-set="24-63"

config-changed hook would fail after the second command with a traceback like this: https://pastebin.ubuntu.com/p/pFRs6thHqC/

Nova's vcpu_pin_set option has been being deprecated since Train: [1]

[1] https://docs.openstack.org/releasenotes/nova/train.html#deprecation-notes

[Nikolay Vinogradov (nikolay.vinogradov)]

It looks like the workaround is to just set vcpu-pin-set to any value:

$ grep 'vcpu_pin_set\|cpu_shared_set\|cpu_dedicated_set' /etc/nova/nova.conf
cpu_shared_set = 8-23
cpu_dedicated_set = 24-63

[Edward Hope-Morley (hopem)]

Going to get this fixed since the workaround is resulting in a fair amount of confusion

[Edward Hope-Morley (hopem)]

Patch: https://review.opendev.org/c/openstack/charm-nova-compute/+/774629