Automatic merge from submit-queue
Kubelet can retrieve host IP even when apiserver has not been contacted
fixes https://github.com/kubernetes/kubernetes/issues/26590, fixes https://github.com/kubernetes/kubernetes/issues/6558
Right now the kubelet expects to get the hostIP from the kubelet's local nodeInfo cache. However, this will be empty if there is no api-server (or the apiServer has not yet been contacted).
In the case of static pods, this change means the downward api can now be used to populate hostIP.