* 'node.kubernetes.io/network-unavailable=:NoSchedule' if NetworkUnavailable is true
          * 'node.kubernetes.io/disk-pressure=:NoSchedule' if DiskPressure is true
          * 'node.kubernetes.io/memory-pressure=:NoSchedule' if MemoryPressure is true
          * 'node.kubernetes.io/out-of-disk=:NoSchedule' if OutOfDisk is true

    * If the serialization type is application/vnd.kubernetes.protobuf, and protobuf marshaling is not implemented for the requested API resource type, a '406 Not Acceptable is returned'.
    * If the serialization type is 'application/json':
    * If serialization fails, and the original status code was an failure (e.g. 4xx or 5xx), the original status code will be returned.

## Urgent Upgrade Notes

### (No, really, you MUST read this before you upgrade)

- Client-go: Clients can request protobuf and json and correctly negotiate with the server for JSON for CRD objects, allowing all client libraries to request protobuf if it is available.  If an error occurs negotiating a watch with the server, the error is immediately return by the client `Watch()` method instead of being sent as an `Error` event on the watch stream. ([#84692](https://github.com/kubernetes/kubernetes/pull/84692),...

  - if more than one QueueingHintFn returns QueueImmediately, it queues Pod to activeQ.
  - If no QueueingHintFn returns QueueImmediately and more than one plugin returns QueueAfterBackoff, it queues Pod to backoffQ if Pod is backing off, or to activeQ if Pod's backoff has already finished.
  - If all QueueingHintFn return QueueSkip, it puts this pod back to the unschedulable pod pool

    * annotation is service.beta.kubernetes.io/azure-load-balancer-internal-subnet and its
    * value is the subnet name (not the subnet ARM ID).  If omitted, the default is the
    * master subnet.  It is ignored if the service is not on Azure, if the type is not
    * LoadBalancer, or if the load balancer is not internal.

## Before Upgrading

* If you need to downgrade from 1.10 to 1.9.x, downgrade to v1.9.6 to ensure PV and PVC objects can be deleted properly.

* In-place node upgrades to this release from versions 1.7.14, 1.8.9, and 1.9.4 are not supported if using subpath volumes with PVCs.  Such pods should be drained from the node first.

  
  1. If you experienced problems with Services not syncing to iptables correctly, you can disable the feature by passing `--feature-gates=MinimizeIPTablesRestore=false` to kube-proxy (and file a bug if this fixes it). (This might also be detected by seeing the value of kube-proxy's `sync_proxy_rules_iptables_partial_restore_failures_total` metric rising.)

- One new field "InternalTrafficPolicy" in Service is added.
  It specifies if the cluster internal traffic should be routed to all endpoints or node-local endpoints only.
  "Cluster" routes internal traffic to a Service to all endpoints.
  "Local" routes traffic to node-local endpoints only, and traffic is dropped if no node-local endpoints are ready.

removed the `.ImagePullPolicy` field in the v1alpha2 API version. Instead it's set statically to `IfNotPresent` for all required images. If you want to always pull the latest images before cluster init (as `Always` would do), run `kubeadm config images pull` before each `kubeadm init`. If you don't want the kubelet to pull any images at `kubeadm init` time, for example if you don't have an internet connection, you can also run `kubeadm config images pull` before `kubeadm init` or side-load the images some...