IIS 7 and Above
Application Initialization Module
How To: Using Application Initialization for Multi-Server Environment...
Re: How To: Using Application Initialization for Multi-Server Environ...
Dec 11, 2014 08:28 AM|Perkinsville|LINK
You will need to install it on all the servers.
You can make requests only to http: // localhost:80. Requests to any other hostname:Port will not work, so if your sites run from any other place, use a different port or cannot be reached via LOCALHOST, then you need to find another solution.