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Assign Pods to Nodes

This page shows how to assign a Kubernetes Pod to a particular node in a Kubernetes cluster.

• Before you begin
• Add a label to a node
• Create a pod that gets scheduled to your chosen node
• What’s next

Before you begin

You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using Minikube, or you can use one of these Kubernetes playgrounds:

• Katacoda
• Play with Kubernetes

Add a label to a node

1. List the nodes in your cluster:

    kubectl get nodes
   

   The output is similar to this:

    NAME      STATUS    AGE     VERSION
    worker0   Ready     1d      v1.6.0+fff5156
    worker1   Ready     1d      v1.6.0+fff5156
    worker2   Ready     1d      v1.6.0+fff5156
   

2. Chose one of your nodes, and add a label to it:

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

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

3. Verify that your chosen node has a disktype=ssd label:

    kubectl get nodes --show-labels
   

   The output is similar to this:

    NAME      STATUS    AGE     VERSION            LABELS
    worker0   Ready     1d      v1.6.0+fff5156     ...,disktype=ssd,kubernetes.io/hostname=worker0
    worker1   Ready     1d      v1.6.0+fff5156     ...,kubernetes.io/hostname=worker1
    worker2   Ready     1d      v1.6.0+fff5156     ...,kubernetes.io/hostname=worker2
   

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

Create a pod that gets scheduled to your chosen node

This pod configuration file describes a pod that has a node selector, disktype: ssd. This means that the pod will get scheduled on a node that has a disktype=ssd label.

pod.yaml
apiVersion: v1 kind: Pod metadata: name: nginx labels: env: test spec: containers: - name: nginx image: nginx imagePullPolicy: IfNotPresent nodeSelector: disktype: ssd

1. Use the configuration file to create a pod that will get scheduled on your chosen node:

    kubectl create -f https://k8s.io/docs/tasks/configure-pod-container/pod.yaml
   

2. Verify that the pod is running on your chosen node:

    kubectl get pods --output=wide
   

   The output is similar to this:

    NAME     READY     STATUS    RESTARTS   AGE    IP           NODE
    nginx    1/1       Running   0          13s    10.200.0.4   worker0
   

What’s next

Learn more about labels and selectors.