This is the page where I can buy a Reserved Instance:
I can click Add to Cart, but then how do I know in which region/AZ is the RI?
This is the page where I can buy a Reserved Instance:
I can click Add to Cart, but then how do I know in which region/AZ is the RI?
The instances are reserved in whichever region your console was set to when you initiated the purchase:
You can also click on the "Only show offerings that reserve capacity" (shown) if you want to purchase Zonal-scoped RIs.
Before you click on "Purchased Reserved Instances" you are in the EC2 console under a specific region and this is the region you are buying in. If you want to select a different region, change your region by clicking the Region name in the top-right banner of the AWS console.
Normally, reserved instances can be used in any AZ. If you want to reserve capacity in an AZ and lock in the RI into a specific AZ, click the checkbox labeled "Only Show Offerings that reserve capacity" in top-right of the Purchase Reserved Instance dialogue/search box and you will see listing for specific AZs.