Jobs (instead of Pods) by default.
  * Pods can now consume Secret data in environment variables and inject those
environment variables into a container’s command-line args.
  * Stable version of Heapster which scales up to 1000 nodes: more metrics, reduced
latency, reduced cpu/memory consumption (~4mb per monitored node).
  * Pods now have a security context which allows users to specify:

- `LabelSelectors` specified in `topologySpreadConstraints` were validated to ensure that pods are scheduled as expected. Existing pods with invalid `LabelSelectors` could be updated, but new pods were required to specify valid `LabelSelectors`. ([#111802](https://github.com/kubernetes/kubernetes/pull/111802), [@maaoBit](https://github.com/maaoBit))

  * Stop 'kubectl drain' deleting pods with local storage.
  * Add `kubectl rollout status`
* Security/Auth
  * L7 LB controller and disk attach controllers run on master, so nodes do not need those privileges.
  * Setting TLS1.2 minimum
  * `kubectl create secret tls` command
  * Webhook Token Authenticator
  * **beta** PodSecurityPolicy objects limits use of security-sensitive features by pods.
* Kubectl

tolerations](https://kubernetes.io/docs/concepts/configuration/assign-pod-node/). This feature allows you to specify rules for "repelling" pods from nodes by default, which enables use cases like dedicated nodes and reserving nodes with special features for pods that need those features. We've also added a `NoExecute` taint type that evicts already-running pods, and an associated `tolerationSeconds` field to tolerations to delay the eviction for a specified amount of time. As before, taints are created...

  Previously, when unschedulable Pods are updated, the scheduler always put Pods back to activeQ/backoffQ. But, actually not all updates to Pods make Pods schedulable, especially considering many scheduling constraints nowadays are immutable.

- **Cluster Lifecycle**
  - [alpha] Ensure critical cluster infrastructure pods (Heapster, DNS, etc.) can schedule by evicting regular pods when necessary to make the critical pods schedule. ([docs](http://kubernetes.io/docs/admin/rescheduler/#guaranteed-scheduling-of-critical-add-on-pods)) ([kubernetes/features#62](https://github.com/kubernetes/enhancements/issues/62))

  Similarly you can also access  kubelet's `/pods` endpoint to fetch a list of Pods bound to that node by granting the caller `nodes/pods` permission in RBAC.
  Similarly you can also access kubelet's `/configz` endpoint to fetch kubelet's configuration by granting the caller `nodes/configz` permission in RBAC.

* Admit critical pods in the kubelet ([#38836](https://github.com/kubernetes/kubernetes/pull/38836), [@bprashanth](https://github.com/bprashanth))
* assign -998 as the oom_score_adj for critical pods (e.g. kube-proxy) ([#39114](https://github.com/kubernetes/kubernetes/pull/39114), [@dchen1107](https://github.com/dchen1107))

- There is now support for collecting pod logs under `/var/log/pods/NAMESPACE_NAME_UID` to stackdriver with `k8s_pod` resource type. ([#74502](https://github.com/kubernetes/kubernetes/pull/74502), [@Random-Liu](https://github.com/Random-Liu))

* Improve efficiency of preemption logic in clusters with many pending pods. ([#72895](https://github.com/kubernetes/kubernetes/pull/72895), [@bsalamat](https://github.com/bsalamat))
* Fix scheduling starvation of pods in cluster with large number of unschedulable pods. ([#72619](https://github.com/kubernetes/kubernetes/pull/72619), [@everpeace](https://github.com/everpeace))