New Post: How to Add New Servers in sharepoint 2013 farm with Autospinstaller

Why not simply use the same approach you used for the first install? Add your new servers to the XML in the required areas, and run AutoSPInstaller on each new server to assign its role. For example, if you previously provisioned, say, Excel Services on your first App server APPSERV1, to provision it on the new app server APPSERV2 as part of its role, you would modify the corresponding element like this:

Provision="APPSERV1,APPSERV2"

BTW, how do you consider a "search/index" server to be different than a "crawl" server?

Brian