When attempting to set the 'CMDB Item' field in a Knowledge Bank template as mandatory, we found that it could not be done.
I'd like to suggest that the ability to make the CMDB Item (Service) field mandatory be implemented, as the Service Window (quick-searching) functonality relies on it as a type of matching. I've also seen many instances where the CMDB Item field has not been populated, which adds no value to the knowledge bank articles or tickets for that matter.
Without a 'Service' or 'CI' linked to a Knowledge Article, searching is severely hampered and we're unable to provide a services list for customers to search and match on using Knowledge As You Log.