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Node Selectors

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In this section, we will take a look at Node Selectors in Kubernetes

We add new property called Node Selector to the spec section and specify the label.

• The scheduler uses these labels to match and identify the right node to place the pods on. ``` apiVersion: v1 kind: Pod metadata: name: myapp-pod spec: containers:
  • name: data-processor image: data-processor nodeSelector: size: Large ```

• To label nodes

  Syntax

  $ kubectl label nodes <node-name> <label-key>=<label-value>
  

  Example

  $ kubectl label nodes node-1 size=Large
  

• To create a pod definition ``` apiVersion: v1 kind: Pod metadata: name: myapp-pod spec: containers:
  • name: data-processor image: data-processor nodeSelector: size: Large

    $ kubectl create -f pod-definition.yml ```

Node Selector - Limitations

• We used a single label and selector to achieve our goal here. But what if our requirement is much more complex.

• For this we have Node Affinity and Anti Affinity

K8s Reference Docs

• https://kubernetes.io/docs/concepts/scheduling-eviction/assign-pod-node/#nodeselector