Open source has become the de facto standard for building the software that underpins the complex infrastructure that runs everything from your favorite mobile apps to your company’s barely usable expense tool. Over the course of the last few years, a lot of new software is being deployed on top of Kubernetes, the tool for managing large server clusters running containers that Google open sourced five years ago.

Today, Kubernetes is the fastest growing open-source project and earlier this month, the bi-annual KubeCon+CloudNativeCon conference attracted almost 8,000 developers to sunny Barcelona, Spain, making the event the largest open-source conference in Europe yet.

To talk about how Kubernetes came to be, I sat down with Craig McLuckie, one of the co-founders of Kubernetes at Google (who then went on to his own startup, Heptio, which he sold to VMware); Tim Hockin, another Googler who was an early member on the project and was also on Google’s Borg team; and Gabe Monroy, who co-founded Deis, one of the first successful Kubernetes startups, and then sold it to Microsoft, where he is now the lead PM for Azure Container Compute (and often the public face of Microsoft’s efforts in this area).

To set the stage a bit, it’s worth remembering where Google Cloud and container management were five years ago.