When it comes to a cluster of machines the job of scheduling applications becomes an exercise for the operations team. Today for many organizations scheduling is handled by the fine folks running that team. Yet, unfortunately the use of a human scheduler requires humans to keep track of where applications are running. Sometimes this means using complicated error-prone spreadsheets or a configuration management tool with Puppet. Either way these tools don’t really offer the robust scheduling that is necessary to react to these real time events. This is where Kubernetes fits in.
If you think of the datacenter in this way then Kubernetes would be it’s datacenter operating system.