Cost Savings Seen by CarRentals.com Full Move to the Cloud
Have you started your cloud migration, or heard stories about companies seeing increased spend as they’ve moved to the cloud? Perhaps you’ve read about companies, including Expedia Group, who have met with increasing infrastructure costs and wonder whether the move is worth it, financially?
Can we provide a proof point to reassure ourselves and others that the cloud can save money?
CarRentals.com is one of the smaller brand divisions within Expedia Group. Being small has some advantages — in many ways we are a microcosm of the larger company, with much of the complexity and responsibilities that the bigger brands in Expedia Group have. But our laser focus on a single line of business supported by a smaller, nimbler team, puts us in a great position to execute and share our learnings and observations.
For example, we were the first brand to move to a fully Cloud-native shopping and booking stack, with our first bookings in AWS in October 2015. There are many benefits to moving to the cloud including faster delivery, higher availability, and better resiliency; but in this post, I want to specifically share what we’ve seen from a cost perspective. With this long operating history, we can answer the question of cloud spend over time.
First, I want to set the context by giving you a history of the CarRentals.com cloud journey. We started by doing a lift and shift of a monolithic PHP backend, three different domain APIs supporting our brands, and three different UI applications. The self-contained monolith made it easier to move to AWS, but it also made it harder for us to optimize and see the real benefits of the cloud — we were still slow in our delivery and had a brittle code base. Really all that had changed was that managing our data center was easier and more in our engineering team’s control.
Earlier this year, we completed a project which allowed us to combine our brands onto a single UI application and domain, while also refactoring major parts of the monolithic backend into a set of AWS microservices. As with any major integration project, this was rolled out in phases which meant that for most of 2017 and into 2018, we had two stacks in production which increased our footprint. Only recently have we scaled back on our legacy stack.
So how have we done in terms of cloud cost breakdown? Pretty well. In 2015 our costs were mostly data center, and jumped when we first moved into the cloud. We had just done a lift and shift with no optimizations, no dynamic scaling (that’s a big one), and minimal leveraging of AWS technologies beyond EC2 instances. 2017 starts to show a different picture as we built out more of our new stack and were better able to tune our instances based on our use of microservices. This trend continued into this year, and while I can’t share specific numbers, our spend for 2018 is projected to not only be lower than it was when we first moved into the cloud, but to also show significant savings over the start of our cloud journey.
These proof points give an important lesson for the rest of Expedia Group and any organization undertaking a cloud migration. You will likely see an initial increase in costs from “blind migration” to the cloud, but it will put you in a great position to follow up with optimizations as you start to take advantage of native cloud offerings, review the sizes and usages of your instances, and ultimately come to a steady state. We have the proof point to show the promises are true, and now that we’ve launched our new stack, are looking forward to the next phase of growth and innovation in CarRentals.com!
