Question / Problem:
How does a separate KTA web server communicate with the rest of the installation?
Answer / Solution:
KTA web servers do not connect directly to the database. Instead all work is performed through calls to the core services on the app server. When a KTA web server is installed (without installing a combined web/app server), the installer prompts for the fully qualified address to an existing KTA app server:
This ends up setting the CoreServicesLocation setting in the web.config, seen here in the Configuration Utility:
This location can be either a single KTA app server, or a load balancer that has several app servers.
If the components of the app servers have been customized, this setting should point to app servers that have the WCF/Core Services installed: