kubeadm during initialization of master and slave nodes need to make
several API calls directly to the node where it is running or master.
In environments with http/https proxies, user might accidentally
have configuration where connections to API would go over proxy instead
of directly.
User can re-run kubeadm with corrected NO_PROXY variable. Example:
$ NO_PROXY=* kubeadm join ...
ce9a13ef13