### kubeadm
* A new label and taint is used for marking the master. The label is `node-role.kubernetes.io/master=""` and the taint has the effect `NoSchedule`. Tolerate the `node-role.kubernetes.io/master="":NoSchedule` taint to schedule a workload on the master (a networking DaemonSet for example).
* The kubelet API is now secured, only cluster admins are allowed to access it.

### SIG Network

- The ip-masq-agent will now be scheduled in all nodes except master due to NoSchedule/NoExecute tolerations. ([#66260](https://github.com/kubernetes/kubernetes/pull/66260), [@tanshanshan](https://github.com/tanshanshan))

      long delay,
      TimeUnit timeUnit,
      ScheduledExecutorService executorService) {
    TrustedListenableFutureTask<O> task = TrustedListenableFutureTask.create(callable);
    Future<?> scheduled = executorService.schedule(task, delay, timeUnit);
    /*
     * Even when the user interrupts the task, we pass `false` to `cancel` so that we don't
     * interrupt a second time after the interruption performed by TrustedListenableFutureTask.

- Ensured that the `node-role.kubernetes.io/master` taint is applied to the master with NoSchedule on GCE. ([#78183](https://github.com/kubernetes/kubernetes/pull/78183), [@cheftako](https://github.com/cheftako))

- Fixed a scheduler panic when using PodAffinity. ([#82841](https://github.com/kubernetes/kubernetes/pull/82841), [@Huang-Wei](https://github.com/Huang-Wei))
- Take the context as the first argument of Schedule. ([#82119](https://github.com/kubernetes/kubernetes/pull/82119), [@wgliang](https://github.com/wgliang))

- Fixed missing `kubelet_volume_stats_*` metrics. ([#133890](https://github.com/kubernetes/kubernetes/pull/133890), [@huww98](https://github.com/huww98)) [SIG Instrumentation and Node]
- Fixed occasional schedule delays when a static `PersistentVolume` is created. ([#133929](https://github.com/kubernetes/kubernetes/pull/133929), [@huww98](https://github.com/huww98)) [SIG Scheduling and Storage]

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

labels.excluded_doc_urls=検索対象から除外するURL
labels.user_agent=ユーザーエージェント
labels.web_crawling_button_create=作成
labels.web_crawling_button_create_job=新しいジョブの作成
labels.crawler_configuration=全般の設定
labels.crawler_title_edit=全般の設定
labels.schedule=スケジュール
labels.enabled=有効
labels.day_for_cleanup=以前のドキュメントを削除
labels.day=日
labels.crawl_button_update=更新
labels.none=なし
labels.crawling_thread_count=同時クローラー設定
labels.incremental_crawling=最終更新日時の確認

- Truncates a message if it hits the NoteLengthLimit when the scheduler records an event for the pod that indicates the pod has failed to schedule. ([#98715](https://github.com/kubernetes/kubernetes/pull/98715), [@carlory](https://github.com/carlory)) [SIG Scheduling]

## Changelog since v1.14.6

### Other notable changes

* When the number of jobs exceeds 500, cronjob should schedule without error. ([#77475](https://github.com/kubernetes/kubernetes/pull/77475), [@liucimin](https://github.com/liucimin))