After upgrading OSP9->OSP10->OSP11 Cinder API service is not working properly. In order to fix it we need to following on the nodes where cinder api services is running:
sed -i s/cinder.api.middleware.sizelimit/oslo_middleware.sizelimit/ /etc/cinder/api-paste.ini
systemctl restart httpd
Assigning to Dan for review.
Dan, this one might be best covered by using this bug to add a 'Known Issue' in the Release Notes that we can remove when the dependent bug is fixed, or in the 'Post Upgrade Notes' of your working document.