问题
I want to get the specific value of an annotation into a kubectl custom columns field. I can get all the current annotations on a resource like so:
kubectl get pvc -o custom-columns=NAME:.metadata.name,"ANNOTATIONS":.metadata.annotations -n monitoring
This returns a map:
NAME ANNOTATIONS
prometheus-k8s-db-prometheus-k8s-0 map[pv.kubernetes.io/bind-completed:yes pv.kubernetes.io/bound-by-controller:yes volume.beta.kubernetes.io/storage-provisioner:kubernetes.io/aws-ebs]
prometheus-k8s-db-prometheus-k8s-1 map[pv.kubernetes.io/bind-completed:yes pv.kubernetes.io/bound-by-controller:yes volume.beta.kubernetes.io/storage-provisioner:kubernetes.io/aws-ebs]
And considering kubectl -o custom-columns uses JSONpath to the best of my knowledge, I figured I could do this:
kubectl get pvc -o custom-columns=NAME:.metadata.name,"ANNOTATIONS":".metadata.annotations['pv.kubernetes.io/bind-completed']" -n monitoring
But it seems not. Is there a way to do this?
回答1:
Okay, I figured this out. It's easier than I thought.
Annotations is a standard JSON element when it's returned. The problem is that kubectl's JSONPath parser has problems with dots in elements, so you just have to escape them. Here's an example:
kubectl get pvc -o custom-columns=NAME:.metadata.name,"ANNOTATIONS":".metadata.annotations.pv\.kubernetes\.io/bind-completed" -n monitoring
NAME ANNOTATIONS
prometheus-k8s-db-prometheus-k8s-0 yes
prometheus-k8s-db-prometheus-k8s-1 yes
来源：https://stackoverflow.com/questions/57418535/kubectl-use-custom-columns-output-with-maps