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Comment by cthalupa | Hacker News Reader

Amazon doesn't know how many resources you're going to spin up and how many ENIs they will need, so it's hard to really tell you how big of a subnet to create.

You can also use the AWS NAT Gateway which doesn't require you run your own NAT instance

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Annoyingly, the VPC NAT Gateway is more expensive than running your own nat instance. If your traffic is low enough to be handled by a t2.small or lower, it's cheaper to run your own. Most of my NATs are nanos or micros.

AWS also double-dips on the traffic charges for the VPC NAT - you're charged for the traffic it transfers, but you're also charged for the same traffic in the general bill, from what I've been able to glean. Given that traffic is where AWS is not competitively priced, it's something to be cautious of.

NAT Gateway support bursts up to 10 Gbps[1] and t2.small something like 125-200 Mbps [2]. For production use cases this can make a huge difference.

[1] http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/vpc-na...

[2] https://stackoverflow.com/questions/18507405/ec2-instance-ty...

Sure, but you also don't need a big NAT Gateway if you're doing the majority of your external chatter via an ELB. Our setup is basically production load goes through an ELB, and incidental traffic goes through the default route (the NAT), so the NAT really only handles traffic like me ssh'ing in and wanting to install a tool, or config management setting up a new server.

But yes, if you're going to be sending big traffic through the NAT, a t2.small doesn't have the network performance.

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