Advanced scheduling
One of the strongest suits of Kubernetes is its powerful yet flexible scheduler. The job of the scheduler, put simply, is to choose nodes to run newly created pods. In theory the scheduler could even move existing pods around between nodes, but in practice it doesn’t do that at the moment and instead leaves this functionality for other components.
By default, the scheduler follows several guiding principles, including:
- Split pods from the same replica set or stateful set across nodes
- Schedule pods to nodes that have enough resources to satisfy the pod requests
- Balance out the overall resource utilization of nodes
This is pretty good default behavior, but sometimes you may want better control over specific pod placement. Kubernetes 1.6 introduced several advanced scheduling options that give you fine-grained control over which pods are scheduled or not scheduled on which nodes as well as which pods are to be scheduled together or separately.
Let’s review...
