Credentials error with Kubernetes

[smondet]

By installing/configuring gcloud a bit manually, on a GCE node I had coclobas refusing to start jobs:

Error from kubernetes:

error: You must be logged in to the server (the server has asked for the client to provide credentials)

(cf. issue kubernetes/kubernetes#30617)

I ran that:

gcloud config set container/use_client_certificate True

and then the gcloud container clusters get-credentials $CLUSTER needs to
happen (make sure by restarting Coclobas).

I'm not sure if my config of gcloud was the problem, or if we should investigate this further.