Kubectl: Cannot fetch multi-container pod logs by selector

Created on 22 Jun 2017 · 6Comments · Source: kubernetes/kubectl

kubectl version:

$ kubectl version
Client Version: version.Info{Major:"1", Minor:"6", GitVersion:"v1.6.1", GitCommit:"b0b7a323cc5a4a2019b2e9520c21c7830b7f708e", GitTreeState:"clean", BuildDate:"2017-04-03T20:44:38Z", GoVersion:"go1.7.5", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"6", GitVersion:"v1.6.1", GitCommit:"b0b7a323cc5a4a2019b2e9520c21c7830b7f708e", GitTreeState:"clean", BuildDate:"2017-04-03T20:33:27Z", GoVersion:"go1.7.5", Compiler:"gc", Platform:"linux/amd64"}

What happened:

When attempting to fetch the logs of a pod using a selector kubectl seems to demand a container name, but then does not allow a container name to be passed.

$ kubectl logs --selector app=kube-dns
Error from server (BadRequest): a container name must be specified for pod kube-dns-2325730542-99bh1, choose one of: [kubedns dnsmasq dnsmasq-metrics healthz]
$ kubectl logs --selector app=kube-dns --container  kubedns
error: a container cannot be specified when using a selector (-l)

What you expected to happen:

With kubectl logs --selector app=kube-dns I expected to see the logs for all containers in all my kube-dns labeled pods.
With kubectl logs --selector app=kube-dns --container kubedns I expected to see the logs for all the kubedns containers in all my pod kube-dns labeled pods.

Also acceptable would be if one of those two commands failed with one of the above errors, but then the other command worked.

How to reproduce it:

Attempt to get logs for a multi-pod container using a selector.

Source