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.
The reason for the bump is the new functionality of the
k8s.io/utils/exec package which allows
- to get a hold of the process' std{out,err} as `io.Reader`s
- to `Start` a process and `Wait` for it
This should help on addressing #70890 by allowing to wrap std{out,err}
of the process to be wrapped with a `io.limitedReader`.
It also updates
- k8s.io/kubernetes/pkg/probe/exec.FakeCmd
- k8s.io/kubernetes/pkg/kubelet/prober.execInContainer
- k8s.io/kubernetes/cmd/kubeadm/app/phases/kubelet.fakeCmd
to implement the changed interface.
The dependency on 'k8s.io/utils/pointer' to the new version has also
been bumped in some staging repos:
- apiserver
- kube-controller-manager
- kube-scheduler
The kubelet allows you to set `--pod-infra-container-image`
(also called `PodSandboxImage` in the kubelet config),
which can be a custom location to the "pause" image in the case
of Docker. Other CRIs are not supported.
Set the CLI flag for the Docker case in flags.go using
WriteKubeletDynamicEnvFile().
