Plugin does not seem to support private GKE clusters through a proxy

[mzwennes]

We have a setup with a private GKE cluster and a bastion through which we connect to the GKE cluster. In order to make this work we set the proxy-url value in the Kubeconfig.

The Kubeconfig looks something like this:

- cluster:
    certificate-authority-data: XXX
    proxy-url: http://localhost:8884
    server: https://172.11.0.6
  name: cluster

This works fine for default kubectl commands:

➜ k get ns
NAME               STATUS   AGE
bsr                Active   301d
cert-manager       Active   342d
cluster-health     Active   342d
default            Active   343d

However the kubectl outdated command seems to throw a timeout error:

➜ k outdated
  Searching for images ⠴failed to list namespaces: Get "https://172.11.0.6/api/v1/namespaces": dial tcp 172.11.0.6:443: i/o timeout

What I have tried so far:

• Test on a cluster with public access (works)
• Manually passing the --kubeconfig param (does not work)

Any ideas if this is related to the oudated plugin not properly handling proxies?