How do I use kubectl to get K8S nodes which do not have any labels? Also , how do I fetch K8S pods which do not have any labels?
There is no specific way to check for no labels in general without listing every possible label. You would have to do this client side.
there is no way to check the nodes/pods that dont have labels. Instead what you can do is check for nodes/pods for specific label
follow the below steps
add label mylabel=k8s
master $ kubectl get no
NAME STATUS ROLES AGE VERSION
master Ready master 51m v1.11.3
node01 Ready <none> 50m v1.11.3
master $
master $
master $ kubectl label nodes node01 mylabel=k8s
node/node01 labeled
master $
master $ kubectl get no -L mylabel
NAME STATUS ROLES AGE VERSION MYLABEL
master Ready master 52m v1.11.3
node01 Ready <none> 52m v1.11.3 k8slist nodes that has label mylabel=k8s
master $ kubectl get no -l mylabel=k8s
NAME STATUS ROLES AGE VERSION
node01 Ready <none> 53m v1.11.3
master $list the nodes that doesnt have label mylabel=k8s
master $ kubectl get no -l mylabel!=k8s
NAME STATUS ROLES AGE VERSION
master Ready master 53m v1.11.3You have to leverage kubectl -o flag and go-template output:
kubectl get nodes -o go-template='{{range .items }}{{if .metadata.labels }}{{else}}{{printf "%s\n" .metadata.name}}{{ end }}{{end}}This command will show only nodes which do not have any labels. The same can be used for pods:
kubectl get pods --all-namespaces -o go-template='{{range .items }}{{if .metadata.labels }}{{else}}{{printf "%s\n" .metadata.name}}{{ end }}{{end}}'according to the official documentation I dont think there is a way of doing that, but you can do something like that with the negation of equality:
kubectl get nodes --selector=kubernetes.io/hostname!=node_host_namebasically you can select everything that doesn't have a particular label, you can also chain selectors
More reading: https://kubernetes.io/docs/concepts/overview/working-with-objects/field-selectors/