  Cloud users can significantly reduce their cost (by up to 60\%) by reserving
virtual machines (VMs) for long periods (1 or 3 years) rather than acquiring
them on demand. Unfortunately, reserving VMs exposes users to \emph{demand
risk} that can increase cost if their expected future demand does not
materialize. Since accurately forecasting demand over long periods is
challenging, users often limit their use of reserved VMs. To mitigate demand
risk, Amazon operates a Reserved Instance Marketplace (RIM) where users may
publicly list the remaining time on their VM reservations for sale at a price
they set. The RIM enables users to limit demand risk by either selling VM
reservations if their demand changes, or purchasing variable- and shorter-term
VM reservations that better match their demand forecast horizon. Clearly, the
RIM's potential to mitigate demand risk is a function of its price
characteristics. However, to the best of our knowledge, historical RIM prices
have neither been made publicly available nor analyzed. To address the problem,
we have been monitoring and archiving RIM prices for 1.75 years across all 69
availability zones and 22 regions in Amazon's Elastic Compute Cloud (EC2). This
paper provides a first look at this data and its implications for
cost-effectively provisioning cloud infrastructure.
