What's the difference between EC2 Reserved Instance Linux/UNIX (Amazon VPC) and Linux/UNIX?

Question

My instance is running on Linux (kubernetes deployed by kops). From the billing I saw they are classified as "Linux/UNIX", but I think it is deployed in VPC via kops.

Now I want to buy reserved instance, and the choices of platform has two:

• Linux/UNIX (Amazon VPC)
• Linux/UNIX

Which one should I use? What are the difference?

BTW, once I bought a RI, do I have to wait to the next day to see the reservation coverage from billing UI? Can I see if it covers some of my running instance immediately?

Answer 1

I have access to multiple aws accounts and I found something interesting.

As of today (2020-02-26), when looking at ca-central-1 region's platforms when trying to buy reserved instances, I only see Linux/UNIX , and I don't see Linux/UNIX (Amazon VPC) in the list:

This list is the same in both older and recent AWS accounts.

When I look at us-east-1 region's platforms when trying to buy reserved instances, I see the same list as ca-central-1 when using the recent account **But when I use a much older aws account which used to have m1 ec2 instances (which can't be created anymore), here's what I see:

Note that we already reserved a plan for an m1 instance back in the days (which is now expired) so that could be related to why I see two kind platform for each of them.

Funny thing is I can only reserve Linux/UNIX (Amazon VPC) , not Linux/UNIX as you can see from the two screenshots:

Linux/UNIX list empty on older account:

Linux/UNIX (Amazon VPC) list not empty on older account:

So my assumption is if you see both, Linux/UNIX (Amazon VPC) will be the one you need, otherwise, use Linux/UNIX .

Update 2020-02-27: I did purchase them, I will verify usage once it's effective, but I'm quite sure everything is fine.

Update 2020-03-06: I confirm it works as expected. I have 100% coverage in both regions starting from 2020-02-27 in the billing dashboard.

Answer 2

Linux/UNIX is EC2-Classic which is legacy.

"The EC2-Classic platform was introduced in the original release of Amazon EC2."

AWS EC2-Classic

Use Linux/UNIX (Amazon VPC) which will spawn the instance in your own VPC.