Among other things, each instance will need to have a growing number of hosts as bindings in IIS. There are additional OS-configurations that will need to be made outside of what Beanstalk's intentions are, but I believe the answer to the question will be the same.
So my question is simply, how are the new instances created? Are they as basic as just spinning up a new default instance with just my application, or do the new instances appear with all of the same custom IIS binding/OS configuration as others (my minimum instances) have?
Elastic beanstalk create new instances in the following way: 1. Create new instance based on ami defined in the environment configuration. On the created instance: 2. When instance created run bootstrap scripts on instance in order to setup it one. 3. Downloads from s3 current version of the application bundle. 4. Runs elastic beanstalk hooks which runs configuration files from .ebextentions and perform deploy of application. 5. Application up and running:)