• k8s
• StudyNotes
• NodeSelectors+NodeAffinity

k8s/StudyNotes/NodeSelectors & Node Affinity

• Example is different size nodes, with labels Large, Medium, Small

• Get labels on node

  kubectl get nodes node01 --show-labels

• (Older)nodeSelector, no logic. Ind pod-def.yaml, add to spec: nodeSelector:

  apiVersion:
  kind: Pod
  metadata:
    name: myapp-pod
  spec:
    containers:
    - name: data-processor
      image: dataproc
    nodeSelector:
      size: Large

  • label node with

    kubectl label node 
    
     2. (Newer)Node Affinity and anti affinity. 
       * Node Affinity more flexabe but complex, e.g. pick large node {{{
    spec:
      containers:
        ...
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoreDuringExecution:
            nodeSeletorTerms:
            - matchExpressions:
              - key: size
                operator: In
                values:
                - Large

  • 2x types of Node affinity
    1. requiredDuringSchedulingIgnoredDuringExecution
    2. preferredDuringSchedulingIgnoredDuringExecution
    3. future planned
       1. requiredDuringSchedulingRequiredDuringExecution
       2. preferredDuringSchedulingRequiredDuringExecution
  • Node Affinity, can have different operator's:
    • operator: In
    • operator: Exists