<p><a href="https://www.linkedin.com/in/sean-bastille">Sean Bastille</a>, Chief Architect, Verizon Media<br/></p><p>Effectively using Reserved Instances (RIs) is a cornerstone component for managing costs in AWS. Proper evaluations of RIs can be challenging. There are many tools, each with their own nuances, that help evaluate RI needs.<br/></p><p>At Verizon Media, we built a tool to help manage our RIs, called <a href="https://github.com/yahoo/ariel.git">Ariel</a>, and today we are pleased to announce that we have open-sourced Ariel so that you can use and customize it for your own needs.<br/></p><p><b>Why We Built Ariel</b><br/></p><p><b></b></p><p>The main reason we chose to build Ariel was due to the limitations of currently available solutions. Amazon provides RI recommendations, both as an executive service, and through Cost Explorer, however, these tools:</p><p><b></b></p><ul><li>Target break-even RI Utilization, without the flexibility to tune</li><li>Evaluate per-account RI need, or company-wide RI need, but are not capable of combining the views<br/></li></ul><p>Additionally, Ariel has a sophisticated configuration allowing for multiple passes of RI evaluations targeting usage slope based thresholds and allowing for simultaneous classic and convertible RI recommendations. Whereas there are 3rd party vendor tools that help optimize RI utilization, we did not find an open source solution that was free to use and could be expanded upon by a community.<br/></p><p><b></b></p><p><b>How Ariel Reduces EC2 Costs</b></p><p><b></b></p><p>RIs are a core component of cost management at Verizon Media. By using RIs, we reduce EC2 costs in some workloads by as much as 70%, which in turn reduces our AWS bill by about 25%.  </p><p>Ariel helps us evaluate RI purchases by determining:</p><ul><li>What our current RI demand is, taking into consideration existing RIs</li><li>Floating RIs, which are not used in the purchasing account, but are available to the company</li><li>Which specific accounts to make purchases in so the costs can be more closely aligned with P&amp;Ls</li></ul><p><b></b></p><p><b>Explore and Contribute</b></p><p><b></b></p><p>We invite you to use <a href="https://github.com/yahoo/ariel.git">Ariel</a> and join our community by developing more features and contributing to the code. If you have any questions, feel free to <a href="mailto:ariel-support@verizonmedia.com">email my team</a>.</p>