• How to count the amount of labels on a node: 
    kubectl describe node <node_name>
  • What is the value set to a particular label?
    • Again checking via the kubectl describe command.
  • How to apply a label to a node: 
    kubectl label node node01 color=blue
  • How to create a new deployment called blue and 3 replicas: 
    kubectl create deployment blue --image=nginx --replicas=3
  • How to check for taints: 
    kubectl describe node <node_name> | grep Taints
  • Therefore the pods can be scheduled on the node if there are no Taints.
  • How set Node Affinity to place pods on particular deployment: 
    kubectl edit deployment blue

    Check under the pod specification: ``` spec: containers:

    • images: nginx imagePullPolicy: Always name: nginx resources: () terminationMessagePath: /dev/termination-log terminationMessagePolicy: File dnsPolicy: ClusterFirst restartPolicy: Always schedulerName: default-scheduler securityContext: () terminationGracePeriodSeconds: 30 
      Then we add the Affinity Spec:

      spec: affinity: nodeAffinity: requiredDuringSchedulingIgnoredDuringExecution: nodeSelectorTerms:

      • matchExpressions:
        • key: color operator: In values:
          • blue containers:
    • images: nginx imagePullPolicy: Always name: nginx resources: () terminationMessagePath: /dev/termination-log terminationMessagePolicy: File dnsPolicy: ClusterFirst restartPolicy: Always schedulerName: default-scheduler securityContext: () terminationGracePeriodSeconds: 30 ```
  • Save the file and the pod should then be edited.
  • Find out which nodes pods are placed on: 
    kubectl get pod -o wide
  • Create a new deployment called red and apply it to the controlplane node only. First we need the yaml file. 
    kubectl create deployment red --image=nginx --replicas=2 --dry-run=client -o yaml > <yaml_file_name>

    Edit the file so it looks like this: ``` spec: affinity: nodeAffinity: requiredDuringSchedulingIgnoredDuringExecution: nodeSelectorTerms: - matchExpressions: - key: node-role.kubernetes.io/master operator: Exists values: - blue containers:

    • images: nginx imagePullPolicy: Always name: nginx resources: () status() ```
  • Then create the deployment with kubectl create -f red.yaml

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