// The scheduler will prefer to schedule pods to nodes that satisfy
  // the affinity expressions specified by this field, but it may choose
  // a node that violates one or more of the expressions. The node that is
  // most preferred is the one with the greatest sum of weights, i.e.
  // for each node that meets all of the scheduling requirements (resource

  Example: suppose you develop a custom plugin that denies Pods that have a `schedulable=false` label. 

## Changes by Kind

### Bug or Regression

- Fixed a bug that a pod may remain unscheduled if any PreFilter plugin returns nodes that do not exist. ([#124559](https://github.com/kubernetes/kubernetes/pull/124559), [@chengjoey](https://github.com/chengjoey)) [SIG Scheduling and Testing]

	any NetworkPolicy whose spec.podSelector targets them. Pods that are
	targeted by NetworkPolicies accept traffic that is accepted by any of
	the NetworkPolicies (and nothing else), and pods that are not targeted
	by any NetworkPolicy accept all traffic by default.
	Action Required:
	When upgrading to Kubernetes 1.7 (and a network plugin that supports
	the new NetworkPolicy v1 semantics), to ensure full behavioral

- `Kubelet` no longer creates certain legacy iptables rules by default.
  It is possible that this will cause problems with some third-party components
  that improperly depended on those rules. If this affects you, you can run

**[Pod priority and preemption](https://kubernetes.io/docs/concepts/configuration/pod-priority-preemption/) is now enabled by default.** Note that this means that pods from *any* namespace can now request priority classes that compete with and/or cause preemption of critical system pods that are already running. If that is not desired, disable the PodPriority feature by setting `--feature-gates=PodPriority=false` on the kube-apiserver, kube-scheduler, and kubelet components before upgrading to 1.11....

The behavior of some watch calls to the server when filtering on fields was incorrect. If watching objects with a filter, when an update was made that no longer matched the filter a DELETE event was correctly sent. However, the object that was returned by that delete was not the (correct) version before the update, but instead, the newer version. That meant the new object was not matched by the filter. This was a regression from behavior between cached watches on the server side and uncached watches,...

  network plugins which was first widely noticed in 1.16 (though some users saw it
  earlier than that, possibly only with specific network plugins). If you were previously
  using ethtool to disable checksum offload on your primary network interface, you should
  now be able to stop doing that. ([#92035](https://github.com/kubernetes/kubernetes/pull/92035), [@danwinship](https://github.com/danwinship)) [SIG Network and Node]

This release contains changes that address the following vulnerabilities:

### CVE-2021-25735: Validating Admission Webhook does not observe some previous fields

A security issue was discovered in kube-apiserver that could allow node
updates to bypass a Validating Admission Webhook. You are only affected
by this vulnerability if you run a Validating Admission Webhook for Nodes

- Fix a bug that Pods could stuck in the unschedulable pod pool