Kubernetes - How to list all pods running in a particular instance group?

Question

How can I list, using command line, all the pods running in the nodes of a particular instance group?

For example, if I have instancegroup "Foo", which has let's say three nodes, N1, N2, and N3, that in turn have pods A and B running on N1, pods C, D and E running on N2, and pod F running on N3.... how can I, using kops/kubectl, make query with input "Foo" and output "A, B, C, D, E, F"?

I know that you can query a particular node and list all the pods in it, but I want to query an instancegroup, with many nodes, and get all the pods across all the nodes, with no namespace constraint.

Thanks!

Answer 1

One way would be to assign labels to the nodes in your InstanceGroup, perhaps with the name of the instance group (for simplicity) and then use a combination of kubectl commands to query.

So in your InstanceGroup spec set nodeLabels to be ig: Foo (see https://github.com/kubernetes/kops/blob/master/docs/instance_groups.md#adding-taints-or-labels-to-an-instance-group) for details and then run:

kubectl get pods -o wide --all-namespaces | grep -F -f <(kubectl get nodes -l ig=Foo --no-headers | awk '{print $1}')