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.