CODEWITHSUNDEEP
kubectl
Jason
Jason

Reputation: 5027

How can I work with arrays using `kubectl` with `custom-columns`?

In the reference docs, they say you can print the image of a container like so.

kubectl get pod test-pod -o custom-columns=CONTAINER:.spec.containers[0].name,IMAGE:.spec.containers[0].image

However, when I try any command that has brackets, I get an error message and no output.

no matches found: custom-columns=CONTAINER:.spec.containers[0].name,IMAGE:.spec.containers[0].image

if I just specify something like .spec.containers it will output the entire array similar to this:

  [map[image:weaveworksplugins/scope-traffic-control:latest imagePullPolicy:Always name:weavescope-traffic-control-plugin resources:map[requests:map[cpu:100m]] securityContext:map[privileged:true procMount:Default] terminationMessagePath:/dev/termination-log terminationMessagePolicy:File volumeMounts:[map[mountPath:/var/run/docker.sock name:docker-sock] map[mountPath:/var/run/scope/plugins name:scope-plugins]
...

Kubectl version information

Client Version: version.Info{Major:"1", Minor:"15", GitVersion:"v1.15.2", GitCommit:"f6278300bebbb750328ac16ee6dd3aa7d3549568", GitTreeState:"clean", BuildDate:"2019-08-05T16:54:35Z", GoVersion:"go1.12.7", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"14", GitVersion:"v1.14.2", GitCommit:"66049e3b21efe110454d67df4fa62b08ea79a19b", GitTreeState:"clean", BuildDate:"2019-05-16T16:14:56Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"linux/amd64"}

Upvotes: 2

Views: 1071

Answers (1)

coderanger
coderanger

Reputation: 54251

That's a shell (probably ZSH?) error message, not related to kubectl. You need to quote the string that contains the [ and ] so they don't get interpreted as shell metachars.

kubectl get pod test-pod \
  -o custom-columns='CONTAINER:.spec.containers[0].name,IMAGE:.spec.containers[0].image'

Upvotes: 7

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