I hesitate to bring this point to your attention, because Mike you’re truly awesome in your videos (and that’s not nearly enough)!
Any rate, the diagram at around 3:30 shows 1 EC2 instance with multiple ENIs attached to it, and that’s all good, except the subnets of the ENIs must be in the same AZ, you cannot have one instance that is present in multiple AZs. Multiple ENIs are ok, as long as they are in different subnets within the SAME AZ and same VPC.
You are correct.
I will review this and write up update the slides and lecture.
FYI, you can actually attach multiple ENIs to the same subnet, however it can cause unpredictable effects. but it can be done. http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-eni.html
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