Issue 1:
https://k8s-gubernator.appspot.com/build/kubernetes-jenkins/logs/kubernetes-e2e-gke/12566/

Failed: [k8s.io] Kubectl client [k8s.io] Update Demo should create and stop a replication controller [Conformance] {Kubernetes e2e suite}

/go/src/k8s.io/kubernetes/_output/dockerized/go/src/k8s.io/kubernetes/test/e2e/kubectl.go:210
Expected error:
<*errors.errorString | 0xc820381c10>: {
s: "Error running &{/workspace/kubernetes/platforms/linux/amd64/kubectl [kubectl --server=https://104.198.218.12 --kubeconfig=/workspace/.kube/config get pods update-demo-nautilus-e438n -o template --template={{if (exists . \"status\" \"containerStatuses\")}}{{range .status.containerStatuses}}{{if (and (eq .name \"update-demo\") (exists . \"state\" \"running\"))}}true{{end}}{{end}}{{end}} --namespace=e2e-tests-kubectl-vpkad] [] <nil> failed to find client for version v1: error: google: could not find default credentials. See https://developers.google.com/accounts/docs/application-default-credentials for more information.\n [] <nil> 0xc820938680 exit status 1 <nil> true [0xc820de2710 0xc820de2728 0xc820de2740] [0xc820de2710 0xc820de2728 0xc820de2740] [0xc820de2720 0xc820de2738] [0xabd2f0 0xabd2f0] 0xc820e038c0}:\nCommand stdout:\n\nstderr:\nfailed to find client for version v1: error: google: could not find default credentials. See https://developers.google.com/accounts/docs/application-default-credentials for more information.\n\nerror:\nexit status 1\n",
}
Error running &{/workspace/kubernetes/platforms/linux/amd64/kubectl [kubectl --server=https://104.198.218.12 --kubeconfig=/workspace/.kube/config get pods update-demo-nautilus-e438n -o template --template={{if (exists . "status" "containerStatuses")}}{{range .status.containerStatuses}}{{if (and (eq .name "update-demo") (exists . "state" "running"))}}true{{end}}{{end}}{{end}} --namespace=e2e-tests-kubectl-vpkad] [] <nil> failed to find client for version v1: error: google: could not find default credentials. See https://developers.google.com/accounts/docs/application-default-credentials for more information.
[] <nil> 0xc820938680 exit status 1 <nil> true [0xc820de2710 0xc820de2728 0xc820de2740] [0xc820de2710 0xc820de2728 0xc820de2740] [0xc820de2720 0xc820de2738] [0xabd2f0 0xabd2f0] 0xc820e038c0}:
Command stdout:

stderr:
failed to find client for version v1: error: google: could not find default credentials. See https://developers.google.com/accounts/docs/application-default-credentials for more information.

error:
exit status 1

not to have occurred
/go/src/k8s.io/kubernetes/_output/dockerized/go/src/k8s.io/kubernetes/test/e2e/framework/util.go:2006

Previous issues for this test: #28565 #29072 #29390 #29659

Issue 2:
error: google: could not find default credentials. See https://developers.google.com/accounts/docs/application-default-credentials for more information. appears in a lot of flakes. Speculation is that the metadata server is slow to respond.

So far, these are the issues where this message has popped up:

#28569

#28565

#28523

#28507

#28493

#28439

#28437

#28429

#28426

#28420

#28293

#27976

#27839

#27715

#27156

#26715

#26490

Sample failed run: https://k8s-gubernator.appspot.com/build/kubernetes-jenkins/logs/kubernetes-e2e-gke/10664

@cjcullen since this is dealing with auth, I'm initially assigning to you. Feel free to reassign to someone more appropriate.