PodSubnet validates against the corresponding cluster "--node-cidr-mask-size" of the kube-controller-manager, it fail if the values are not compatible.
  kubeadm no longer sets the node-mask automatically on IPv6 deployments, you must check that your IPv6 service subnet mask is compatible with the default node mask /64 or set it accordingly.

	* Mechanism of adding `federation domain maps` to kube-dns deployment via `--federations` flag is superseded by adding/updating `federations` key in `kube-system/kube-dns` configmap. If user is using kubefed tool to join cluster federation, adding federation domain maps to kube-dns is already taken care by `kubefed join` and does not need further action.

* Make DaemonSet respect critical pods annotation when scheduling. ([#42028](https://github.com/kubernetes/kubernetes/pull/42028), [@janetkuo](https://github.com/janetkuo))
* Implement the update feature for DaemonSet. ([#41116](https://github.com/kubernetes/kubernetes/pull/41116), [@lukaszo](https://github.com/lukaszo))

Call             Core type    Result

make(T, n)       slice        slice of type T with length n and capacity n
make(T, n, m)    slice        slice of type T with length n and capacity m

make(T)          map          map of type T
make(T, n)       map          map of type T with initial space for approximately n elements

make(T)          channel      unbuffered channel of type T

consequence, all volume mounts in containers are now `rslave` on Linux by default. To make this default work in all Linux environments the entire mount tree should be marked as shareable, e.g. via `mount --make-rshared /`. All Linux distributions that use systemd already have the root directory mounted as rshared and hence they need not do anything. In Linux environments without systemd we recommend running `mount --make-rshared /` during boot before docker is started, ([@jsafrane](https://github.com/jsafrane))...

  1. When configuring a dual-stack cluster, the user must specify both `--node-cidr-mask-size-ipv4` and `--node-cidr-mask-size-ipv6` to set the per-node IP mask sizes, instead of the previous `--node-cidr-mask-size` flag.
  2. The `--node-cidr-mask-size` flag is mutually exclusive with `--node-cidr-mask-size-ipv4` and `--node-cidr-mask-size-ipv6`.

  // The value is typically used to determine whether a container is ready to
  // accept traffic.
  optional bool ready = 4;

  // RestartCount holds the number of times the container has been restarted.
  // Kubelet makes an effort to always increment the value, but there
  // are cases when the state may be lost due to node restarts and then the value
  // may be reset to 0. The value is never negative.
  optional int32 restartCount = 5;

- QueueingHint implementation for NodeUnschedulable is reverted because we found potential scenarios where events that make Pods schedulable could be missed. ([#122326](https://github.com/kubernetes/kubernetes/pull/122326), [...

* Add flag "--include-uninitialized" to kubectl annotate, apply, edit-last-applied, delete, describe, edit, get, label, set. "--include-uninitialized=true" makes kubectl commands apply to uninitialized objects, which by default are ignored if the names of the objects are not provided. "--all" also makes kubectl commands apply to uninitialized objects. Please see the [initializer](https://kubernetes.io/docs/admin/extensible-admission-controllers/) doc for more details. ([#5049...

 Extended resources cannot be overcommitted, so make sure that request and limit are equal
 if both are present in a container spec.

 - The default Bootstrap Token created with `kubeadm init` v1.8 expires
 and is deleted after 24 hours by default to limit the exposure of the
 valuable credential. You can create a new Bootstrap Token with
 `kubeadm token create` or make the default token permanently valid by specifying