Assign Pods to Nodes using Node Affinity

    You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:

    Your Kubernetes server must be at or later than version v1.10. To check the version, enter .

    1. List the nodes in your cluster, along with their labels:

      The output is similar to this:

      1. NAME STATUS ROLES AGE VERSION LABELS
      2. worker0 Ready <none> 1d v1.13.0 ...,kubernetes.io/hostname=worker0
      3. worker1 Ready <none> 1d v1.13.0 ...,kubernetes.io/hostname=worker1
      4. worker2 Ready <none> 1d v1.13.0 ...,kubernetes.io/hostname=worker2
    2. Chose one of your nodes, and add a label to it:

      1. kubectl label nodes <your-node-name> disktype=ssd

      where <your-node-name> is the name of your chosen node.

      1. kubectl get nodes --show-labels

      The output is similar to this:

      In the preceding output, you can see that the worker0 node has a disktype=ssd label.

    This manifest describes a Pod that has a requiredDuringSchedulingIgnoredDuringExecution node affinity,disktype: ssd. This means that the pod will get scheduled only on a node that has a disktype=ssd label.

    1. apiVersion: v1
    2. kind: Pod
    3. metadata:
    4. spec:
    5. nodeAffinity:
    6. requiredDuringSchedulingIgnoredDuringExecution:
    7. nodeSelectorTerms:
    8. - matchExpressions:
    9. - key: disktype
    10. operator: In
    11. values:
    12. - ssd
    13. containers:
    14. - name: nginx
    15. image: nginx
    16. imagePullPolicy: IfNotPresent
    1. Apply the manifest to create a Pod that is scheduled onto your chosen node:

      1. kubectl apply -f https://k8s.io/examples/pods/pod-nginx-required-affinity.yaml
    2. Verify that the pod is running on your chosen node:

      1. kubectl get pods --output=wide

    This manifest describes a Pod that has a preferredDuringSchedulingIgnoredDuringExecution node affinity,disktype: ssd. This means that the pod will prefer a node that has a disktype=ssd label.

    pods/pod-nginx-preferred-affinity.yaml Assign Pods to Nodes using Node Affinity - 图2

    1. apiVersion: v1
    2. metadata:
    3. name: nginx
    4. spec:
    5. affinity:
    6. nodeAffinity:
    7. preferredDuringSchedulingIgnoredDuringExecution:
    8. - weight: 1
    9. preference:
    10. matchExpressions:
    11. - key: disktype
    12. operator: In
    13. values:
    14. - ssd
    15. containers:
    16. - name: nginx
    17. image: nginx
    18. imagePullPolicy: IfNotPresent
    1. Apply the manifest to create a Pod that is scheduled onto your chosen node:

      1. kubectl apply -f https://k8s.io/examples/pods/pod-nginx-preferred-affinity.yaml

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