This tests the PDB status update path in DisruptionController and
asserts that conflicting writes (with eviciton handler) are handled
gracefully.
This adds the client-go fake.Clientset into our tests, because that is
the layer required for injecting update failures.
This also adds a TestMain so that DisruptionController logs can be
enabled during test. e.g.,
go test ./pkg/controller/disruption -v -args -v=4
The race test is interested only if all volumes are mounted and pod is
started, it does not need any special CPU.
It de-flakes the test when running on a tight node.
Without this it fails after deployments were switched from
extensions to apps with
```
E0902 11:25:51.197420 1 reflector.go:283] github.com/kubernetes-incubator/cluster-proportional-autoscaler/pkg/autoscaler/k8sclient/k8sclient.go:96: Failed to watch *v1.Node: unknown (get nodes)
E0902 11:25:53.118490 1 reflector.go:283] github.com/kubernetes-incubator/cluster-proportional-autoscaler/pkg/autoscaler/k8sclient/k8sclient.go:96: Failed to watch *v1.Node: unknown (get nodes)
E0902 11:25:54.997493 1 reflector.go:283] github.com/kubernetes-incubator/cluster-proportional-autoscaler/pkg/autoscaler/k8sclient/k8sclient.go:96: Failed to watch *v1.Node: unknown (get nodes)
E0902 11:25:57.097423 1 reflector.go:283] github.com/kubernetes-incubator/cluster-proportional-autoscaler/pkg/autoscaler/k8sclient/k8sclient.go:96: Failed to watch *v1.Node: unknown (get nodes)
E0902 11:25:59.097417 1 reflector.go:283] github.com/kubernetes-incubator/cluster-proportional-autoscaler/pkg/autoscaler/k8sclient/k8sclient.go:96: Failed to watch *v1.Node: unknown (get nodes)
I0902 11:25:59.697325 1 k8sclient.go:221] Falling back to extensions/v1beta1, error using apps/v1: deployments.apps "calico-typha" is forbidden: User "system:serviceaccount:kube-system:typha-cpha" cannot get resource "deployments/scale" in API group "apps" in the namespace "kube-system"
E0902 11:25:59.699833 1 autoscaler_server.go:120] Update failure: the server could not find the requested resource
```
Ref. https://github.com/kubernetes/test-infra/pull/13709
Work around Linux kernel bug that sometimes causes multiple flows to
get mapped to the same IP:PORT and consequently some suffer packet
drops.
Also made the same update in kubelet.
Also added cross-pointers between the two bodies of code, in comments.
Some day we should eliminate the duplicate code. But today is not
that day.
