- Added `SchedulerPopFromBackoffQ` feature gate that is in beta and enabled by default. Improved scheduling queue behavior by popping pods from the backoffQ when the activeQ is empty. This allows to process potentially schedulable pods ASAP, eliminating a penalty effect of the backoff queue. ([#130772](https://github.com/kubernetes/kubernetes/pull/130772), [@macsko](https://github.com/macsko))...

The Kubernetes in-tree storage plugin to Container Storage Interface (CSI) migration infrastructure is now beta in Kubernetes v1.17. CSI migration was introduced as alpha in Kubernetes v1.14.

## Known Issues
- volumeDevices mapping ignored when container is privileged

- Port mapping now allows the same `containerPort` of different containers to different `hostPort` without naming the mapping explicitly. ([#94494](https://github.com/kubernetes/kubernetes/pull/94494), [@SergeyKanzhelev](https://github.com/SergeyKanzhelev))

- kubectl supports copying files with wild card ([#72641](https://github.com/kubernetes/kubernetes/pull/72641), [@dixudx](https://github.com/dixudx))

   ([#128100](https://github.com/kubernetes/kubernetes/pull/128100), [@yongruilin](https://github.com/yongruilin)) [SIG Architecture and Instrumentation]
- Discarded the output streams of destination path check in kubectl cp when copying from local to pod and added a 3 seconds timeout to this check ([#126652](https://github.com/kubernetes/kubernetes/pull/126652), [@ardaguclu](https://github.com/ardaguclu)) [SIG CLI]

- Improved memory usage of `kube-scheduler` by dropping the `.metadata.managedFields` field that `kube-scheduler` doesn't require. ([#119556](https://github.com/kubernetes/kubernetes/pull/119556), [@linxiulei](https://github.com/linxiulei))

* Added a new `kubeadm upgrade node config` command. ([#64624](https://github.com/kubernetes/kubernetes/pull/64624), [@luxas](https://github.com/luxas))
* kubeadm now makes the CoreDNS container more secure by dropping (root) capabilities and improves the integrity of the container by running the whole container in read-only.  ([#64473](https://github.com/kubernetes/kubernetes/pull/64473), [@nberlee](https://github.com/nberlee))

  for the service, but there is at least one Terminating pod for that service on the node,
  then kube-proxy will send the traffic to the Terminating pod rather than dropping it. This
  patches up a race condition between when a pod is killed and when the external load

* [fluentd-gcp addon] Fluentd will trim lines exceeding 100KB instead of dropping them. ([#52289](https://github.com/kubernetes/kubernetes/pull/52289), [@crassirostris](https://github.com/crassirostris))

* Add limitrange/resourcequota/downward_api  e2e tests for local ephemeral storage ([#52523](https://github.com/kubernetes/kubernetes/pull/52523), [@NickrenREN](https://github.com/NickrenREN))
* Support copying "options" in resolv.conf into pod sandbox when dnsPolicy is Default ([#54773](https://github.com/kubernetes/kubernetes/pull/54773), [@phsiao](https://github.com/phsiao))