There IS a way to get rid of those GUID names for the application pools, and it works, too, although this is a hacky way of doing it; I don't know if anyone else does this, and you certainly do it at your own risk.
Most of the time, these GUID names are created by Sharepoint's managed services. If you look in IIS, you will see under "Sites" a site called "Sharepoint Web Services". These Web Applications all have GUIDs, too.
First thing is to figure out what service they are used by:
How to Know What GUID Goes To What
In IIS, go through the "Sites" and find one that has a GUID name. Most of them will be in the "Sharepoint Web Services" site (which should be running, by the way). Select the Web Application and choose "Advanced". You will see something like this:
Three things of note here:
- Application Pool: you see the GUID of the app pool this Web Application is using.
- Physical Path: If you look at the tail end of the physical path, you can see what service the Application is really using. In the screenshot above, you see it is "SearchService", and it is, indeed, one of those managed Sharepoint Web Services.
- Virtual Path: This is the GUID name for this Web Application (the site itself).
How to Change the Application Pool
- Okay, now create a new application pool to be used by your Search Service, and assign it the proper login account (something like spsearch or whatever you call yours).
- In "Application Pools", select the GUID for the Search Service (which you now know) and click on "View Applications".
- Here you will see a list of Web Applications that are using that particular app pool (there may be more than one). Locate the GUID for the Web Application under "Virtual Path" and select it.
- Look over in the right panel under "Actions" and choose "Change Application Pool".
- Now choose the Application Pool that you created (with a nice name) from the dropdown box.
If the login account has proper credentials, it should begin working immediately.
However, if you create a new web application in SCA, it will create another GUID-named application pool. That's how it works, but you can always change it.