To appreciate what has changed, it’s important to understand how cloud services are built. The vast majority of cloud services have two major components: 1) a “control plane” which is comprised of the API, provisioning system, database, etc; and 2) a “data plane” which is the actual resources that get provisioned via the control plane – in this case, cloud servers. (If you have a networking background, control and data planes may sound familiar.)
These components have different availability characteristics. It’s quite possible for the control plane to be down while the data plane is up (e.g. you can’t add servers because the API is down but your hosted web site is still up) as well as the data plane be down and the control plane up (e.g. the host running your web server crashes but you can create a replacement cloud server via the API).
Historically we have only guaranteed the Cloud Servers data plane and the new SLA adds control plane guarantee as well. This is meaningful for a couple of reasons:
- Apps are increasingly integrating with infrastructure APIs to make dynamic adjustments and thus take on a large dependency on API availability. A control plane guarantee means you can rely on the Cloud Servers API to be there when you need it.
- OpenStack has proven itself and we are ready to guarantee it. Since its launch in the fall of 2012, Cloud Servers has handled approximately 650 million API requests with an overall uptime of 99.95%. At this time, we are guaranteeing a 99.9% control plane availability but have every intention of pushing it higher over time. Note also that we don’t cheat. We count all server side HTTP 5xx errors as unavailability, maintenance is not excluded, and we measure availability monthly.
- Having both control and data plane guarantees means you can build apps the way you want. If you want to build a more traditional static app that doesn’t need to work around data plane failure, you can do that. The data plane guarantee is there. If you want to build an elastic app that integrates with the API to autoscale, you can do that as well. The control plane guarantee is there. No forced complexity. The choice is yours.
While SLAs are important, they are more than legalese to us. They are promises we make to our customers. It’s part of how we deliver Fanatical Support. We hate downtime and we work hard every day to keep our promises and provide you with a powerful and reliable platform so you can do what you do great. Thanks for being a customer, and we hope the new SLA gives you even more confidence in Cloud Servers and OpenStack.