One of the questions in my CKA exam was how to display taints with kubectl. While you can use kubectl describe, it creates a lot of other information too.

Then I found out about jsonpath and it’s similarity to jq

You can display the taints with something like

[code lang=text] for a in $(kubectl get nodes –no-headers | awk ‘{print $1}') do echo $a – $(kubectl get nodes/$a -o jsonpath='{.spec.taints[].key}{":"}{.spec.taints[].effect}') done

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Sample output

[code lang=text] ip-10-10-10-147.eu-west-2.compute.internal – node-role.kubernetes.io/master:NoSchedule ip-10-10-10-159.eu-west-2.compute.internal – :

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So the first one has a taint (it’s the master node) and the second one doesn’t. (maybe I need to hack this a bit more when I have multiple taints but I’ll do that when I have some multi-tainted nodes to play with)

EDIT: Another way as provided by tdodds81

[code lang=text] $ kubectl get nodes -o=custom-columns=NAME:.metadata.name,TAINTS:.spec.taints NAME TAINTS ip-10-10-10-148.eu-west-2.compute.internal [map[effect:NoSchedule key:node-role.kubernetes.io/master]] ip-10-10-10-218.eu-west-2.compute.internal ip-10-10-10-239.eu-west-2.compute.internal ip-10-10-10-249.eu-west-2.compute.internal ip-10-10-10-51.eu-west-2.compute.internal [/code]

And with multi-taints, it looks like this (on a GKE cluster)

[code lang=text] $ kubectl get nodes -o custom-columns=NAME:.metadata.name,TAINTS:.spec.taints NAME TAINTS gke-test-cluster-k8s-n1-highmem-2-nod-589548dd-3z1v [map[effect:NoSchedule key:key1 timeAdded:<nil> value:value1] map[value:value2 effect:NoSchedule key:key2 timeAdded:<nil>]] gke-test-cluster-k8s-n1-highmem-2-nod-7a33f13b-9lwk <none> gke-test-cluster-k8s-n1-highmem-2-nod-7a33f13b-lnvl <none> gke-test-cluster-k8s-n1-highmem-2-nod-7a33f13b-nt49 <none> gke-test-cluster-k8s-n1-highmem-2-nod-7a33f13b-xgbd <none> [/code]