SONOMA, Calif., March 6, 2018 – Open Source Leadership Summit – The Cloud Native Computing Foundation® (CNCF®), which sustains and integrates open source technologies like Kubernetes® and Prometheus™, today announced that Kubernetes is the first project to graduate. To move from incubation to graduate, projects must demonstrate thriving adoption, a documented, structured governance process, and a strong commitment to community success and inclusivity.

https://www.cncf.io/announcement/2018/03/06/cloud-native-computing-foundation-announces-kubernetes-first-graduated-project/

Great news :) shows that Kubernetes is now considered more mature than previously and it definitely shows.