If a Node name in the cluster is already taken and this Node is Ready,
prevent TLS bootsrap on "kubeadm join" and exit early.
This change requires that a new ClusterRole is granted to the
"system:bootstrappers:kubeadm:default-node-token" group to be
able get Nodes in the cluster. The same group already has access
to obtain objects such as the KubeletConfiguration and kubeadm's
ClusterConfiguration.
The motivation of this change is to prevent undefined behavior
and the potential control-plane breakdown if such a cluster
is racing to have two nodes with the same name for long periods
of time.
The following values are validated in the following precedence
from lower to higher:
- actual hostname
- NodeRegistration.Name (or "--node-name") from JoinConfiguration
- "--hostname-override" passed via kubeletExtraArgs
If the user decides to not let kubeadm know about a custom node name
and to instead override the hostname from a kubelet systemd unit file,
kubeadm will not be able to detect the problem.
In output of "kubeadm init", there are two strings for meaning of
bootstrap token which are "bootstraptoken" and "bootstrap-token".
This changes `[bootstraptoken]` to `[bootstrap-token]`.
This follows the pattern `kubectl` uses for logging.
There are two remaining glog.Infof call that cannot be removed easily.
One glog call comes from kubelet validation which calls features.SetFromMap.
The other comes from test/e2e during kernel validation.
Mostly fixeskubernetes/kubeadm#852
Signed-off-by: Chuck Ha <ha.chuck@gmail.com>
As of 1.8.0 kubelet in kubeadm configuration ships with enabled feature
of node certificate autorotation, it makes sense to enable automatic
certificate rotation csr signing. It will help to avoid issues like
described in #53231 and #53237.
