Scheduling

Kubernetes has a built-in scheduler that runs as part of the control plane. It uses advanced logic to schedule pods to the right worker nodes.

Scheduling starts when Kubernetes is asked to run a new pod. This might be you sending a new manifest file to the API server that asks for a new pod, it might be the result of an autoscaling event, or it might even be a self-healing action replacing a failed pod. Either way, as soon as a new pod is requested, it goes into the pending state while the scheduler picks the best node to run it. As soon as a node is identified the pod is scheduled. However, if the scheduler can’t find a suitable node, the pod will stay pending.

Consider the following example. You’re running a Kubernetes cluster with 6 worker nodes and all of your pods have been configured with resource requests and resource limits – resource requests tell the scheduler the minimum amount of CPU and memory a container needs in order to run, whereas...