# Assign Pods to Nodes using Node Affinity LLMS index: [llms.txt](/llms.txt) --- This page shows how to assign a Kubernetes Pod to a particular node using Node Affinity in a Kubernetes cluster. ## Before you begin

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 kubectl version.

## Add a label to a node 1. List the nodes in your cluster, along with their labels: ```shell kubectl get nodes --show-labels ``` The output is similar to this: ```shell NAME STATUS ROLES AGE VERSION LABELS worker0 Ready 1d v1.13.0 ...,kubernetes.io/hostname=worker0 worker1 Ready 1d v1.13.0 ...,kubernetes.io/hostname=worker1 worker2 Ready 1d v1.13.0 ...,kubernetes.io/hostname=worker2 ``` 1. Choose one of your nodes, and add a label to it: ```shell kubectl label nodes disktype=ssd ``` where `` is the name of your chosen node. 1. Verify that your chosen node has a `disktype=ssd` label: ```shell kubectl get nodes --show-labels ``` The output is similar to this: ``` NAME STATUS ROLES AGE VERSION LABELS worker0 Ready 1d v1.13.0 ...,disktype=ssd,kubernetes.io/hostname=worker0 worker1 Ready 1d v1.13.0 ...,kubernetes.io/hostname=worker1 worker2 Ready 1d v1.13.0 ...,kubernetes.io/hostname=worker2 ``` In the preceding output, you can see that the `worker0` node has a `disktype=ssd` label. ## Schedule a Pod using required node affinity 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.

    pods/pod-nginx-required-affinity.yaml
    
apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
        nodeSelectorTerms:
        - matchExpressions:
          - key: disktype
            operator: In
            values:
            - ssd            
  containers:
  - name: nginx
    image: nginx
    imagePullPolicy: IfNotPresent

1. Apply the manifest to create a Pod that is scheduled onto your chosen node: ```shell kubectl apply -f https://k8s.io/examples/pods/pod-nginx-required-affinity.yaml ``` 1. Verify that the pod is running on your chosen node: ```shell 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 ``` ## Schedule a Pod using preferred node affinity 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
    
apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  affinity:
    nodeAffinity:
      preferredDuringSchedulingIgnoredDuringExecution:
      - weight: 1
        preference:
          matchExpressions:
          - key: disktype
            operator: In
            values:
            - ssd          
  containers:
  - name: nginx
    image: nginx
    imagePullPolicy: IfNotPresent

1. Apply the manifest to create a Pod that is scheduled onto your chosen node: ```shell kubectl apply -f https://k8s.io/examples/pods/pod-nginx-preferred-affinity.yaml ``` 1. Verify that the pod is running on your chosen node: ```shell 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 [Node Affinity](/docs/concepts/scheduling-eviction/assign-pod-node/#node-affinity).