Comment 3 for bug 1761405

One thing I think you can do as a workaround is to set the notification driver to 'noop':

https://docs.openstack.org/nova/latest/configuration/config.html#oslo-messaging-notifications

So:

[oslo_messaging_notifications]
driver = noop

in nova.conf; if you set that, nova will still do the work of generating the payload but it won't actually go over RPC.