09-Node-Affinity

Node Affinity

• Take me to the Video Tutorial

In this section, we will talk about “Node Affinity” feature in kubernetes.

The primary feature of Node Affinity is to ensure that the pods are hosted on particular nodes.

• With Node Selectors we cannot provide the advance expressions.

  apiVersion: v1
  kind: Pod
  metadata:
   name: myapp-pod
  spec:
   containers:
   - name: data-processor
     image: data-processor
   nodeSelector:
    size: Large
  

  

  apiVersion: v1
  kind: Pod
  metadata:
   name: myapp-pod
  spec:
   containers:
   - name: data-processor
     image: data-processor
   affinity:
     nodeAffinity:
       requiredDuringSchedulingIgnoredDuringExecution:
          nodeSelectorTerms:
          - matchExpressions:
            - key: size
              operator: In
              values: 
              - Large
              - Medium
  

  

  apiVersion: v1
  kind: Pod
  metadata:
   name: myapp-pod
  spec:
   containers:
   - name: data-processor
     image: data-processor
   affinity:
     nodeAffinity:
       requiredDuringSchedulingIgnoredDuringExecution:
          nodeSelectorTerms:
          - matchExpressions:
            - key: size
              operator: NotIn
              values: 
              - Small
  

  

  apiVersion: v1
  kind: Pod
  metadata:
   name: myapp-pod
  spec:
   containers:
   - name: data-processor
     image: data-processor
   affinity:
     nodeAffinity:
       requiredDuringSchedulingIgnoredDuringExecution:
          nodeSelectorTerms:
          - matchExpressions:
            - key: size
              operator: Exists
  

  

Node Affinity Types

• Available
  • requiredDuringSchedulingIgnoredDuringExecution
  • preferredDuringSchedulingIgnoredDuringExecution
• Planned
  • requiredDuringSchedulingRequiredDuringExecution
  • preferredDuringSchedulingRequiredDuringExecution
  

Node Affinity Types States

K8s Reference Docs

• https://kubernetes.io/docs/tasks/configure-pod-container/assign-pods-nodes-using-node-affinity/
• https://kubernetes.io/blog/2017/03/advanced-scheduling-in-kubernetes/