Assign Pods to Nodes using Node Affinity [page]deterministic

tasks

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

## 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 <none> 1d v1.13.0 ...,kubernetes.io/hostname=worker0 worker1 Ready <none> 1d v1.13.0 ...,kubernetes.io/hostname=worker1 worker2 Ready <none> 1d v1.13.0 ...,kubernetes.io/hostname=worker2 ``` 1. Choose one of your nodes, and add a label to it:

```shell kubectl label nodes <your-node-name> disktype=ssd ``` where `<your-node-name>` 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 <none> 1d v1.13.0 ...,disktype=ssd,kubernetes.io/hostname=worker0 worker1 Ready <none> 1d v1.13.0 ...,kubernetes.io/hostname=worker1 worker2 Ready <none> 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.

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.

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 ```

Learn more about [Node Affinity](/docs/concepts/scheduling-eviction/assign-pod-node/#node-affinity).

Sources

tasks/configure-pod-container/assign-pods-nodes-using-node-affinity.md · doc — “Assign Pods to Nodes using Node Affinity”

Related (6)

part_of {{% heading "prerequisites" %}} — describes conf=1

part_of Add a label to a node — describes conf=1

part_of Schedule a Pod using required node affinity — describes conf=1

part_of Schedule a Pod using preferred node affinity — describes conf=1

part_of {{% heading "whatsnext" %}} — describes conf=1

api_for Affinity — documents API object conf=1

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