How do I get logs from all pods of a Kubernetes replication controller?

Running kubectl logs shows me the stderr/stdout of one Kubernetes container.

How can I get the aggregated stderr/stdout of a set of pods, preferably those created by a certain replication controller?

Solution 1:

You can use labels

kubectl logs -l app=elasticsearch

I've created a small bash script called kubetail that makes this possible. For example to tail all logs for pods named "app1" you can do:

kubetail app1

You can find the script here.

You can get the logs from multiple containers using labels as Adrian Ng suggested:

kubectl logs --selector app=yourappname

In case you have a pod with multiple containers, the above command is going to fail and you'll need to specify the container name:

kubectl logs --selector app=yourappname --container yourcontainername

Note: If you want to see which labels are available to you, the following command will list them all:

kubectl get pod <one of your pods> -o template --template='{{.metadata.labels}}'

...where the output will look something like

map[app:yourappname controller-revision-hash:598302898 pod-template-generation:1]

Note that some of the labels may not be shared by other pods - picking "app" seems like the easiest one