12-NODEAFFINITY

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NODEAFFINITY

the limitions of nodeSelectors are solved using nodeAffinity

yaml file to launch a pod on node with label size( what we did above) using nodeAffinity - (cat >pod-definition.yaml)

apiVersion: v1
 kind: Pod
 metadata:
    name:webapp-pod
	labels:
	   user: hari
spec:
   containers:
      - name: hari-container
        image: nginx
   affinity	
      nodeAffinity:
         requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
               - key: size
                 operator: In 
                 values:
                 - large	 
                 - medium	(if we want to add	two valuess this is how we do it, if we want only one remove medium)  
			  
other operators available area
NotIn (opposite of In)
Exists (if we use exits we dont need to give values field, it just checks if key exists and if it exists then it deploys the pod)

types of node affinity - 
requiredDuringSchedulingIgnoredDuringExecution - if we use this and then the node doesnt have label, then pod is not scheduled 
preferredDuringSchedulingIgnoredDuringExecution - if we use this and then the node doesnt have label, then pod is placed on some other node

after deploying pod , id node label is removed then it doesnt affect the running pod 

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