devops-exercises/topics/kubernetes/exercises/node_selectors/solution.md

Node Selectors

Objectives

1. Apply the label "hw=max" on one of the nodes in your cluster
2. Create and run a Pod called some-pod with the image redis and configure it to use the selector hw=max
3. Explain why node selectors might be limited

Solution

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1. kubectl label nodes some-node hw=max

kubectl run some-pod --image=redis --dry-run=client -o yaml > pod.yaml

vi pod.yaml

spec:
  nodeSelector:
    hw: max

kubectl apply -f pod.yaml

3. Assume you would like to run your Pod on all the nodes with with either hw set to max or to min, instead of just max. This is not possible with nodeSelectors which are quite simplified and this is where you might want to consider node affinity.