Exploring K8s Scheduling

Scheduling: Control plane component that handles scheduling. KubeScheduler: Control plane component that handles scheduling.

Scheduling Process

The Kubernetes scheduler selects a suitable Node for each Pod. It takes into account things like:

Resource requests vs. available node resources.

Various configurations that affect scheduling using node labels.

nodeSelector

You can configure a nodeSelector for your Pods to limit which Node(s) the Pod can be scheduled on. Node selectors use node labels to filter suitable nodes.


kubectl label nodes k8s-worker2 key=value

apiVersion: v1
kind: Pod
metadata:
  name: nodeselector-pod
spec:
  nodeSelector: 
    special: "true"  #It is written in quotes so that it should not interpert it as 
	  containers:      # Boolean
    - name: nginx
      image: nginx:1.19.1

nodeName

You can bypass scheduling and assign a Pod to a specific Node by name using nodeName.


apiVersion: v1
kind: Pod
metadata:
  name: nodename-pod
spec:
  nodeName: <node name>
  containers:
    - name: nginx
      image: nginx:1.19.1