Google open-sourced Kubernetes in 2014, it is a platform for managing containers and services.
Ranked in these QuestionsQuestion Ranking
Pro Very in-depth documentation
The Kubernetes documentation is very detailed and well organized.
Explanations are easy to understand/follow.
Pro Supports high availability deployment on a cluster
Allows zero downtime deployment of new releases on a cluster of machines. So your service can scale, resist even if there is a hardware failure, recover from them, etc.
Con Not specifically a Docker learning resource
While learning about Kubernetes will give you a better understanding of Docker, it's not specifically a learning resource.
This is a better route for someone who already has some Docker experience.
Con Harder to set up
Kubernetes configuration and set up requires some more work than just Docker. Using cloud solutions (like Google Container Engine) simplify this, but it's still a bit harder to learn than let's say