* of DaemonSet Pod already exists, it will be replaced.
    * DaemonSet controller will only perform these operations when creating DaemonSet Pods;
    * and those operations will only modify the Pods of DaemonSet, no changes are made to the
    * `.spec.template` of DaemonSet.

  // If not specified, the pod will be dispatched by default scheduler.
  // +optional
  optional string schedulerName = 19;

  // If specified, the pod's tolerations.
  // +optional
  repeated Toleration tolerations = 22;

  // HostAliases is an optional list of hosts and IPs that will be injected into the pod's hosts
  // file if specified. This is only valid for non-hostNetwork pods.
  // +optional

* Add support for running GCI on the GCE cloud provider ([#25425](https://github.com/kubernetes/kubernetes/pull/25425), [@andyzheng0831](https://github.com/andyzheng0831))
* Implement taints and tolerations ([#24134](https://github.com/kubernetes/kubernetes/pull/24134), [@kevin-wangzefeng](https://github.com/kevin-wangzefeng))

* Fix cluster autoscaler addon permissions so it can access batch/job. ([#69858](https://github.com/kubernetes/kubernetes/pull/69858), [@losipiuk](https://github.com/losipiuk))
* Add tolerations for Stackdriver Logging and Metadata Agents. ([#69737](https://github.com/kubernetes/kubernetes/pull/69737), [@qingling128](https://github.com/qingling128))

  This allows the scheduler to handle cluster events faster with less memory.
  
  Specific node events include updates to taints, tolerations or allocatable.

* Time for attach/detach retry operations has been decreased from 10-12s to 2-6s ([#56974](https://github.com/kubernetes/kubernetes/pull/56974), [@gnufied](https://github.com/gnufied))

### Auth

* Contexts must be named in kubeconfigs. ([#56769](https://github.com/kubernetes/kubernetes/pull/56769), [@dixudx](https://github.com/dixudx))

     ([#73977](https://github.com/kubernetes/kubernetes/pull/73977), [@khenidak](https://github.com/khenidak))
- Add scheduling support for RuntimeClasses. RuntimeClasses can now specify nodeSelector constraints & tolerations, which are merged into the PodSpec for pods using that RuntimeClass. ([#80825](https://github.com/kubernetes/kubernetes/pull/80825), [@tallclair](https://github.com/tallclair))

- Revised the logic for `DaemonSet` rolling update to exclude nodes if scheduling constraints are not met. This eliminates the problem of rolling updates to a `DaemonSet` getting stuck around tolerations. ([#119317](https://github.com/kubernetes/kubernetes/pull/119317), [@mochizuki875](https://github.com/mochizuki875))

### Scheduling

- Tolerations with the same key and effect will be merged into one that has the value of the latest toleration for best effort pods. ([#75985](https://github.com/kubernetes/kubernetes/pull/75985), [@ravisantoshgudimetla](https://github.com/ravisantoshgudimetla))

   ([#122558](https://github.com/kubernetes/kubernetes/pull/122558), [@linxiulei](https://github.com/linxiulei))
- Fixed CEL estimated cost for expressions that perform operations on the result of `map()` operations (e.g., `.map(...).exists(...)` ) to have the correct estimated cost instead of an unbounded cost.
   ([#123562](https://github.com/kubernetes/kubernetes/pull/123562), [@jpbetz](https://github.com/jpbetz))