If I buy a Reserved CDS instance, how do I know I’m only using that purchase and not more instances than I’ve paid for upfront?
Reserved CDS is measured on an hourly basis with an average of 730 hourly units in a monthly cycle, but does not commit to concurrent or parallel consumption of that purchase. As an example:
You purchase one Reserved CDS m5.4xlarge for the Amazon AWS Region US-East. You then use two m5.4xlarge instances simultaneously for 365 hours each in a given monthly billing period.
Only one of these two instances will count toward the Reserved CDS unit previously purchased; the subsequent instance will be charged under the Pay-as-you-go pricing.