Regarding the attaching of ENI to an instance, what does ‘warm attach’ refer to?
Attaching an ENI to an instance when it is stopped.
This question doesn’t make sense.
Attaching an ENI to an instance when it is running
Attaching an ENI to an instance during the launch process
Best Practices for Configuring Elastic Network Interfaces
You can attach an elastic network interface to an instance when it’s running (hot attach), when it’s stopped
(warm attach), or when the instance is being launched (cold attach).