- Kubeadm: fix an issue with the kube-proxy container env. variables ([#84888](https://github.com/kubernetes/kubernetes/pull/84888), [@neolit123](https://github.com/neolit123))

*.test
/hack/.test-cmd-auth

# JUnit test output from ginkgo e2e tests
/junit*.xml

# Mercurial files
**/.hg
**/.hg*

# Vagrant
.vagrant
network_closure.sh

# Local cluster env variables
/cluster/env.sh

# Compiled binaries in third_party
/third_party/pkg

# Also ignore etcd installed by hack/install-etcd.sh
/third_party/etcd*
/default.etcd

* `hack/local-up-cluster.sh` now enables the Node authorizer by default. Authorization modes can be overridden with the `AUTHORIZATION_MODE` environment variable, and the `ENABLE_RBAC` environment variable is no longer used. ([#49812](https://github.com/kubernetes/kubernetes/pull/49812), [@liggitt](https://github.com/liggitt))

* Enable AttachVolumeLimit feature ([#69225](https://github.com/kubernetes/kubernetes/pull/69225), [@gnufied](https://github.com/gnufied))
* [GCP] Added env variables to control CPU requests of kube-controller-manager and kube-scheduler. ([#68823](https://github.com/kubernetes/kubernetes/pull/68823), [@loburm](https://github.com/loburm))

- Fixed a regression in default configurations, which enabled PodDisruptionConditions by default, 
  that prevented the control plane's pod garbage collector from deleting pods that contained duplicated field keys (env. variables with repeated keys or container ports). ([#121379](https://github.com/kubernetes/kubernetes/pull/121379), [@mimowo](https://github.com/mimowo)) [SIG Apps, Auth, Node, Scheduling and Testing]

default in all Kubernetes clients to fix persistently broken connections (https://github.com/kubernetes/client-go/issues/374). If needed, users can tune the feature via the HTTP2_READ_IDLE_TIMEOUT_SECONDS and HTTP2_PING_TIMEOUT_SECONDS environment variables. The feature is disabled if HTTP2_READ_IDLE_TIMEOUT_SECONDS is set to 0. ([#100376](https://github.com/kubernetes/kubernetes/pull/100376), [@liggitt](https://github.com/liggitt)) [SIG API Machinery, CLI, Cloud Provider, Cluster Lifecycle, Instrumentation...

OpenStack cloud provider can now be specified as environment variables. When we convert the OpenStack cloud provider to run in an external process, we can now use the kubernetes Secrets capability to inject the OS_* variables. This way we can specify the cloud configuration as a configmap, and specify secrets for the userid/password information. The configmap is mounted as a file, and the secrets are made available as environment variables. The external controller itself runs as a pod/daemonset. For...

  * “kubectl run” now produces Deployments (instead of ReplicationControllers) and
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).

- When the kubelet is watching a ConfigMap or Secret purely in the context of setting environment variables
  for containers, only hold that watch for a defined duration before cancelling it. This change reduces the CPU

* Add 'kubectl set env' command for setting environment variables inside containers for resources embedding pod templates ([#50998](https://github.com/kubernetes/kubernetes/pull/50998), [@zjj2wry](https://github.com/zjj2wry))