AWS AMI multiple instances

Question

If I have an AMI (EBS backed) from which I launch two instances, would both instances be entirely separate from each other? How does the underlying infrastructure work?

I find it a little overwhelming to get the entire idea to picture. Yes, I'm new to this whole AWS thing.

Answer 1

Yes, they're essentially like "twins" - both are made from the same genetic material (AMI) but each one is an individual person (server). Each instance must be completely decoupled from each other and able to survive on it's own without any knowledge or dependency on it's "twins" (other instances), otherwise you're heading into "conjoined twins" territory in the case of this metaphor!

Assuming each of these instances is for a web server, the thing that binds all of your instances together in the infrastructure is a "Load balancer". This is what will receive the requests to your application and pass it on to one of the web server instances - typically the one that is the least busy.

e.g.

Obviously there's much more to it than this, but this is the general idea.

Answer 2

Just an addition that if you have ip/DNS specific things in your AMI instance that yes, you would have to edit those after the new EC2 was created.