This configuration view gives you the possibility of associating a web application with an Application Pool.
Application Pools are available only for IIS 6 or newer. For previous versions of IIS, any application pool related settings are ignored.
Container Application Pool
Inherit parent item application pool
By selecting this option you do not explicitly specify an associated application pool, and the parent entity application pool (from schema) will be used. This is the default option.
Use installed application pool
Associate this web application with one of the application pools configured in your project.
Use existing application pool
You can associate this web application with an existing application pool on the target IIS server. If you want to place your application in the "DefaultAppPool", just enter DefaultAppPool in this field, but be aware that this pool may not exist on the server.
If the application pool you specify here is not found on the IIS server at install time, the web application will fall-back on the default option of inheriting the parent item pool.
Recycle application pool
When deploying your web application into an existing application pool, you may want to recycle that pool to make sure that the associated worker process is healthy and all the memory is collected, so that your application would start fresh.
You can see a list of all the web applications in a project application pool by selecting that pool in the tree and navigating to the Pool Content tab.