Kuber

API Change
- We have added a new Priority & Fairness rule that exempts all probes (/readyz, /healthz, /livez) to prevent
restarting of "healthy" kube-apiserver instance(s) by kubelet. ([kubernetes/kubernetes101112](https://github.com/kubernetes/kubernetes/pull/101112), [tkashem](https://github.com/tkashem)) [SIG API Machinery]
- Fixes using server-side apply with APIService resources ([kubernetes/kubernetes100714](https://github.com/kubernetes/kubernetes/pull/100714), [kevindelgado](https://github.com/kevindelgado)) [SIG API Machinery, Apps and Testing]
- Regenerate protobuf code to fix CVE-2021-3121 ([kubernetes/kubernetes100501](https://github.com/kubernetes/kubernetes/pull/100501), [joelsmith](https://github.com/joelsmith)) [SIG API Machinery, Apps, Auth, CLI, Cloud Provider, Cluster Lifecycle, Instrumentation, Node and Storage]
- Kubernetes is now built using go1.15.8 ([kubernetes/kubernetes98962](https://github.com/kubernetes/kubernetes/pull/98962), [cpanato](https://github.com/cpanato)) [SIG Cloud Provider, Instrumentation, Release and Testing]
- `TokenRequest` and `TokenRequestProjection` features have been promoted to GA. This feature allows generating service account tokens that are not visible in Secret objects and are tied to the lifetime of a Pod object. See https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/#service-account-token-volume-projection for details on configuring and using this feature. The `TokenRequest` and `TokenRequestProjection` feature gates will be removed in v1.21.
- kubeadm's kube-apiserver Pod manifest now includes the following flags by default "--service-account-key-file", "--service-account-signing-key-file", "--service-account-issuer". ([kubernetes/kubernetes93258](https://github.com/kubernetes/kubernetes/pull/93258), [zshihang](https://github.com/zshihang)) [SIG API Machinery, Auth, Cluster Lifecycle, Storage and Testing]
- A new `nofuzz` go build tag now disables gofuzz support. Release binaries enable this. ([kubernetes/kubernetes92491](https://github.com/kubernetes/kubernetes/pull/92491), [BenTheElder](https://github.com/BenTheElder)) [SIG API Machinery]
- Add WindowsContainerResources and Annotations to CRI-API UpdateContainerResourcesRequest ([kubernetes/kubernetes95741](https://github.com/kubernetes/kubernetes/pull/95741), [katiewasnothere](https://github.com/katiewasnothere)) [SIG Node]
- Add a `serving` and `terminating` condition to the EndpointSlice API.
`serving` tracks the readiness of endpoints regardless of their terminating state. This is distinct from `ready` since `ready` is only true when pods are not terminating.
`terminating` is true when an endpoint is terminating. For pods this is any endpoint with a deletion timestamp. ([kubernetes/kubernetes92968](https://github.com/kubernetes/kubernetes/pull/92968), [andrewsykim](https://github.com/andrewsykim)) [SIG Apps and Network]
- Add dual-stack Services (alpha). This is a BREAKING CHANGE to an alpha API.
It changes the dual-stack API wrt Service from a single ipFamily field to 3
fields: ipFamilyPolicy (SingleStack, PreferDualStack, RequireDualStack),
ipFamilies (a list of families assigned), and clusterIPs (inclusive of
clusterIP). Most users do not need to set anything at all, defaulting will
handle it for them. Services are single-stack unless the user asks for
dual-stack. This is all gated by the "IPv6DualStack" feature gate. ([kubernetes/kubernetes91824](https://github.com/kubernetes/kubernetes/pull/91824), [khenidak](https://github.com/khenidak)) [SIG API Machinery, Apps, CLI, Network, Node, Scheduling and Testing]
- Add support for hugepages to downward API ([kubernetes/kubernetes86102](https://github.com/kubernetes/kubernetes/pull/86102), [derekwaynecarr](https://github.com/derekwaynecarr)) [SIG API Machinery, Apps, CLI, Network, Node, Scheduling and Testing]
- Adds kubelet alpha feature, `GracefulNodeShutdown` which makes kubelet aware of node system shutdowns and result in graceful termination of pods during a system shutdown. ([kubernetes/kubernetes96129](https://github.com/kubernetes/kubernetes/pull/96129), [bobbypage](https://github.com/bobbypage)) [SIG Node]
- AppProtocol is now GA for Endpoints and Services. The ServiceAppProtocol feature gate will be deprecated in 1.21. ([kubernetes/kubernetes96327](https://github.com/kubernetes/kubernetes/pull/96327), [robscott](https://github.com/robscott)) [SIG Apps and Network]
- Automatic allocation of NodePorts for services with type LoadBalancer can now be disabled by setting the (new) parameter
Service.spec.allocateLoadBalancerNodePorts=false. The default is to allocate NodePorts for services with type LoadBalancer which is the existing behavior. ([kubernetes/kubernetes92744](https://github.com/kubernetes/kubernetes/pull/92744), [uablrek](https://github.com/uablrek)) [SIG Apps and Network]
- Certain fields on Service objects will be automatically cleared when changing the service's `type` to a mode that does not need those fields. For example, changing from type=LoadBalancer to type=ClusterIP will clear the NodePort assignments, rather than forcing the user to clear them. ([kubernetes/kubernetes95196](https://github.com/kubernetes/kubernetes/pull/95196), [thockin](https://github.com/thockin)) [SIG API Machinery, Apps, Network and Testing]
- Document that ServiceTopology feature is required to use `service.spec.topologyKeys`. ([kubernetes/kubernetes96528](https://github.com/kubernetes/kubernetes/pull/96528), [andrewsykim](https://github.com/andrewsykim)) [SIG Apps]
- EndpointSlice has a new NodeName field guarded by the EndpointSliceNodeName feature gate.
- EndpointSlice topology field will be deprecated in an upcoming release.
- EndpointSlice "IP" address type is formally removed after being deprecated in Kubernetes 1.17.
- The discovery.k8s.io/v1alpha1 API is deprecated and will be removed in Kubernetes 1.21. ([kubernetes/kubernetes96440](https://github.com/kubernetes/kubernetes/pull/96440), [robscott](https://github.com/robscott)) [SIG API Machinery, Apps and Network]
- External facing API podresources is now available under k8s.io/kubelet/pkg/apis/ ([kubernetes/kubernetes92632](https://github.com/kubernetes/kubernetes/pull/92632), [RenaudWasTaken](https://github.com/RenaudWasTaken)) [SIG Node and Testing]
- Fewer candidates are enumerated for preemption to improve performance in large clusters. ([kubernetes/kubernetes94814](https://github.com/kubernetes/kubernetes/pull/94814), [adtac](https://github.com/adtac))
- Fix conversions for custom metrics. ([kubernetes/kubernetes94481](https://github.com/kubernetes/kubernetes/pull/94481), [wojtek-t](https://github.com/wojtek-t)) [SIG API Machinery and Instrumentation]
- GPU metrics provided by kubelet are now disabled by default. ([kubernetes/kubernetes95184](https://github.com/kubernetes/kubernetes/pull/95184), [RenaudWasTaken](https://github.com/RenaudWasTaken))
- If BoundServiceAccountTokenVolume is enabled, cluster admins can use metric `serviceaccount_stale_tokens_total` to monitor workloads that are depending on the extended tokens. If there are no such workloads, turn off extended tokens by starting `kube-apiserver` with flag `--service-account-extend-token-expiration=false` ([kubernetes/kubernetes96273](https://github.com/kubernetes/kubernetes/pull/96273), [zshihang](https://github.com/zshihang)) [SIG API Machinery and Auth]
- Introduce alpha support for exec-based container registry credential provider plugins in the kubelet. ([kubernetes/kubernetes94196](https://github.com/kubernetes/kubernetes/pull/94196), [andrewsykim](https://github.com/andrewsykim)) [SIG Node and Release]
- Introduces a metric source for HPAs which allows scaling based on container resource usage. ([kubernetes/kubernetes90691](https://github.com/kubernetes/kubernetes/pull/90691), [arjunrn](https://github.com/arjunrn)) [SIG API Machinery, Apps, Autoscaling and CLI]
- Kube-apiserver now deletes expired kube-apiserver Lease objects:
- The feature is under feature gate `APIServerIdentity`.
- A flag is added to kube-apiserver: `identity-lease-garbage-collection-check-period-seconds` ([kubernetes/kubernetes95895](https://github.com/kubernetes/kubernetes/pull/95895), [roycaihw](https://github.com/roycaihw)) [SIG API Machinery, Apps, Auth and Testing]
- Kube-controller-manager: volume plugins can be restricted from contacting local and loopback addresses by setting `--volume-host-allow-local-loopback=false`, or from contacting specific CIDR ranges by setting `--volume-host-cidr-denylist` (for example, `--volume-host-cidr-denylist=127.0.0.1/28,feed::/16`) ([kubernetes/kubernetes91785](https://github.com/kubernetes/kubernetes/pull/91785), [mattcary](https://github.com/mattcary)) [SIG API Machinery, Apps, Auth, CLI, Network, Node, Storage and Testing]
- Migrate scheduler, controller-manager and cloud-controller-manager to use LeaseLock ([kubernetes/kubernetes94603](https://github.com/kubernetes/kubernetes/pull/94603), [wojtek-t](https://github.com/wojtek-t)) [SIG API Machinery, Apps, Cloud Provider and Scheduling]
- Modify DNS-1123 error messages to indicate that RFC 1123 is not followed exactly ([kubernetes/kubernetes94182](https://github.com/kubernetes/kubernetes/pull/94182), [mattfenwick](https://github.com/mattfenwick)) [SIG API Machinery, Apps, Auth, Network and Node]
- Move configurable fsgroup change policy for pods to beta ([kubernetes/kubernetes96376](https://github.com/kubernetes/kubernetes/pull/96376), [gnufied](https://github.com/gnufied)) [SIG Apps and Storage]
- New flag is introduced, i.e. --topology-manager-scope=container|pod.
The default value is the "container" scope. ([kubernetes/kubernetes92967](https://github.com/kubernetes/kubernetes/pull/92967), [cezaryzukowski](https://github.com/cezaryzukowski)) [SIG Instrumentation, Node and Testing]
- New parameter `defaultingType` for `PodTopologySpread` plugin allows to use k8s defined or user provided default constraints ([kubernetes/kubernetes95048](https://github.com/kubernetes/kubernetes/pull/95048), [alculquicondor](https://github.com/alculquicondor)) [SIG Scheduling]
- NodeAffinity plugin can be configured with AddedAffinity. ([kubernetes/kubernetes96202](https://github.com/kubernetes/kubernetes/pull/96202), [alculquicondor](https://github.com/alculquicondor)) [SIG Node, Scheduling and Testing]
- Promote RuntimeClass feature to GA.
Promote node.k8s.io API groups from v1beta1 to v1. ([kubernetes/kubernetes95718](https://github.com/kubernetes/kubernetes/pull/95718), [SergeyKanzhelev](https://github.com/SergeyKanzhelev)) [SIG Apps, Auth, Node, Scheduling and Testing]
- Reminder: The labels "failure-domain.beta.kubernetes.io/zone" and "failure-domain.beta.kubernetes.io/region" are deprecated in favor of "topology.kubernetes.io/zone" and "topology.kubernetes.io/region" respectively. All users of the "failure-domain.beta..." labels should switch to the "topology..." equivalents. ([kubernetes/kubernetes96033](https://github.com/kubernetes/kubernetes/pull/96033), [thockin](https://github.com/thockin)) [SIG API Machinery, Apps, CLI, Cloud Provider, Network, Node, Scheduling, Storage and Testing]
- Server Side Apply now treats LabelSelector fields as atomic (meaning the entire selector is managed by a single writer and updated together), since they contain interrelated and inseparable fields that do not merge in intuitive ways. ([kubernetes/kubernetes93901](https://github.com/kubernetes/kubernetes/pull/93901), [jpbetz](https://github.com/jpbetz)) [SIG API Machinery, Auth, CLI, Cloud Provider, Cluster Lifecycle, Instrumentation, Network, Node, Storage and Testing]
- Services will now have a `clusterIPs` field to go with `clusterIP`. `clusterIPs[0]` is a synonym for `clusterIP` and will be synchronized on create and update operations. ([kubernetes/kubernetes95894](https://github.com/kubernetes/kubernetes/pull/95894), [thockin](https://github.com/thockin)) [SIG Network]
- The ServiceAccountIssuerDiscovery feature gate is now Beta and enabled by default. ([kubernetes/kubernetes91921](https://github.com/kubernetes/kubernetes/pull/91921), [mtaufen](https://github.com/mtaufen)) [SIG Auth]
- The status of v1beta1 CRDs without "preserveUnknownFields:false" now shows a violation, "spec.preserveUnknownFields: Invalid value: true: must be false". ([kubernetes/kubernetes93078](https://github.com/kubernetes/kubernetes/pull/93078), [vareti](https://github.com/vareti))
- The usage of mixed protocol values in the same LoadBalancer Service is possible if the new feature gate MixedProtocolLBService is enabled. The feature gate is disabled by default. The user has to enable it for the API Server. ([kubernetes/kubernetes94028](https://github.com/kubernetes/kubernetes/pull/94028), [janosi](https://github.com/janosi)) [SIG API Machinery and Apps]
- This PR will introduce a feature gate CSIServiceAccountToken with two additional fields in `CSIDriverSpec`. ([kubernetes/kubernetes93130](https://github.com/kubernetes/kubernetes/pull/93130), [zshihang](https://github.com/zshihang)) [SIG API Machinery, Apps, Auth, CLI, Network, Node, Storage and Testing]
- Users can try the CronJob controller v2 using the feature gate. This will be the default controller in future releases. ([kubernetes/kubernetes93370](https://github.com/kubernetes/kubernetes/pull/93370), [alaypatel07](https://github.com/alaypatel07)) [SIG API Machinery, Apps, Auth and Testing]
- VolumeSnapshotDataSource moves to GA in 1.20 release ([kubernetes/kubernetes95282](https://github.com/kubernetes/kubernetes/pull/95282), [xing-yang](https://github.com/xing-yang)) [SIG Apps]
- WinOverlay feature graduated to beta ([kubernetes/kubernetes94807](https://github.com/kubernetes/kubernetes/pull/94807), [ksubrmnn](https://github.com/ksubrmnn)) [SIG Windows]
- API priority and fairness graduated to beta
1.19 servers with APF turned on should not be run in a multi-server cluster with 1.20+ servers. ([kubernetes/kubernetes96527](https://github.com/kubernetes/kubernetes/pull/96527), [adtac](https://github.com/adtac)) [SIG API Machinery and Testing]
- Add LoadBalancerIPMode feature gate ([kubernetes/kubernetes92312](https://github.com/kubernetes/kubernetes/pull/92312), [Sh4d1](https://github.com/Sh4d1)) [SIG Apps, CLI, Cloud Provider and Network]
- Add WindowsContainerResources and Annotations to CRI-API UpdateContainerResourcesRequest ([kubernetes/kubernetes95741](https://github.com/kubernetes/kubernetes/pull/95741), [katiewasnothere](https://github.com/katiewasnothere)) [SIG Node]
- Add a 'serving' and `terminating` condition to the EndpointSlice API.

`serving` tracks the readiness of endpoints regardless of their terminating state. This is distinct from `ready` since `ready` is only true when pods are not terminating.
`terminating` is true when an endpoint is terminating. For pods this is any endpoint with a deletion timestamp. ([kubernetes/kubernetes92968](https://github.com/kubernetes/kubernetes/pull/92968), [andrewsykim](https://github.com/andrewsykim)) [SIG Apps and Network]
- Add support for hugepages to downward API ([kubernetes/kubernetes86102](https://github.com/kubernetes/kubernetes/pull/86102), [derekwaynecarr](https://github.com/derekwaynecarr)) [SIG API Machinery, Apps, CLI, Network, Node, Scheduling and Testing]
- Adds kubelet alpha feature, `GracefulNodeShutdown` which makes kubelet aware of node system shutdowns and result in graceful termination of pods during a system shutdown. ([kubernetes/kubernetes96129](https://github.com/kubernetes/kubernetes/pull/96129), [bobbypage](https://github.com/bobbypage)) [SIG Node]
- AppProtocol is now GA for Endpoints and Services. The ServiceAppProtocol feature gate will be deprecated in 1.21. ([kubernetes/kubernetes96327](https://github.com/kubernetes/kubernetes/pull/96327), [robscott](https://github.com/robscott)) [SIG Apps and Network]
- Automatic allocation of NodePorts for services with type LoadBalancer can now be disabled by setting the (new) parameter
Service.spec.allocateLoadBalancerNodePorts=false. The default is to allocate NodePorts for services with type LoadBalancer which is the existing behavior. ([kubernetes/kubernetes92744](https://github.com/kubernetes/kubernetes/pull/92744), [uablrek](https://github.com/uablrek)) [SIG Apps and Network]
- Document that ServiceTopology feature is required to use `service.spec.topologyKeys`. ([kubernetes/kubernetes96528](https://github.com/kubernetes/kubernetes/pull/96528), [andrewsykim](https://github.com/andrewsykim)) [SIG Apps]
- EndpointSlice has a new NodeName field guarded by the EndpointSliceNodeName feature gate.
- EndpointSlice topology field will be deprecated in an upcoming release.
- EndpointSlice "IP" address type is formally removed after being deprecated in Kubernetes 1.17.
- The discovery.k8s.io/v1alpha1 API is deprecated and will be removed in Kubernetes 1.21. ([kubernetes/kubernetes96440](https://github.com/kubernetes/kubernetes/pull/96440), [robscott](https://github.com/robscott)) [SIG API Machinery, Apps and Network]
- Fewer candidates are enumerated for preemption to improve performance in large clusters ([kubernetes/kubernetes94814](https://github.com/kubernetes/kubernetes/pull/94814), [adtac](https://github.com/adtac)) [SIG Scheduling]
- If BoundServiceAccountTokenVolume is enabled, cluster admins can use metric `serviceaccount_stale_tokens_total` to monitor workloads that are depending on the extended tokens. If there are no such workloads, turn off extended tokens by starting `kube-apiserver` with flag `--service-account-extend-token-expiration=false` ([kubernetes/kubernetes96273](https://github.com/kubernetes/kubernetes/pull/96273), [zshihang](https://github.com/zshihang)) [SIG API Machinery and Auth]
- Introduce alpha support for exec-based container registry credential provider plugins in the kubelet. ([kubernetes/kubernetes94196](https://github.com/kubernetes/kubernetes/pull/94196), [andrewsykim](https://github.com/andrewsykim)) [SIG Node and Release]
- Kube-apiserver now deletes expired kube-apiserver Lease objects:
- The feature is under feature gate `APIServerIdentity`.
- A flag is added to kube-apiserver: `identity-lease-garbage-collection-check-period-seconds` ([kubernetes/kubernetes95895](https://github.com/kubernetes/kubernetes/pull/95895), [roycaihw](https://github.com/roycaihw)) [SIG API Machinery, Apps, Auth and Testing]
- Move configurable fsgroup change policy for pods to beta ([kubernetes/kubernetes96376](https://github.com/kubernetes/kubernetes/pull/96376), [gnufied](https://github.com/gnufied)) [SIG Apps and Storage]
- New flag is introduced, i.e. --topology-manager-scope=container|pod.
The default value is the "container" scope. ([kubernetes/kubernetes92967](https://github.com/kubernetes/kubernetes/pull/92967), [cezaryzukowski](https://github.com/cezaryzukowski)) [SIG Instrumentation, Node and Testing]
- NodeAffinity plugin can be configured with AddedAffinity. ([kubernetes/kubernetes96202](https://github.com/kubernetes/kubernetes/pull/96202), [alculquicondor](https://github.com/alculquicondor)) [SIG Node, Scheduling and Testing]
- Promote RuntimeClass feature to GA.
Promote node.k8s.io API groups from v1beta1 to v1. ([kubernetes/kubernetes95718](https://github.com/kubernetes/kubernetes/pull/95718), [SergeyKanzhelev](https://github.com/SergeyKanzhelev)) [SIG Apps, Auth, Node, Scheduling and Testing]
- Reminder: The labels "failure-domain.beta.kubernetes.io/zone" and "failure-domain.beta.kubernetes.io/region" are deprecated in favor of "topology.kubernetes.io/zone" and "topology.kubernetes.io/region" respectively. All users of the "failure-domain.beta..." labels should switch to the "topology..." equivalents. ([kubernetes/kubernetes96033](https://github.com/kubernetes/kubernetes/pull/96033), [thockin](https://github.com/thockin)) [SIG API Machinery, Apps, CLI, Cloud Provider, Network, Node, Scheduling, Storage and Testing]
- The usage of mixed protocol values in the same LoadBalancer Service is possible if the new feature gate MixedProtocolLBSVC is enabled.
"action required"
The feature gate is disabled by default. The user has to enable it for the API Server. ([kubernetes/kubernetes94028](https://github.com/kubernetes/kubernetes/pull/94028), [janosi](https://github.com/janosi)) [SIG API Machinery and Apps]
- This PR will introduce a feature gate CSIServiceAccountToken with two additional fields in `CSIDriverSpec`. ([kubernetes/kubernetes93130](https://github.com/kubernetes/kubernetes/pull/93130), [zshihang](https://github.com/zshihang)) [SIG API Machinery, Apps, Auth, CLI, Network, Node, Storage and Testing]
- Users can try the CronJob controller v2 using the feature gate. This will be the default controller in future releases. ([kubernetes/kubernetes93370](https://github.com/kubernetes/kubernetes/pull/93370), [alaypatel07](https://github.com/alaypatel07)) [SIG API Machinery, Apps, Auth and Testing]
- VolumeSnapshotDataSource moves to GA in 1.20 release ([kubernetes/kubernetes95282](https://github.com/kubernetes/kubernetes/pull/95282), [xing-yang](https://github.com/xing-yang)) [SIG Apps]
- + `TokenRequest` and `TokenRequestProjection` features have been promoted to GA. This feature allows generating service account tokens that are not visible in Secret objects and are tied to the lifetime of a Pod object. See https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/#service-account-token-volume-projection for details on configuring and using this feature. The `TokenRequest` and `TokenRequestProjection` feature gates will be removed in v1.21.
+ kubeadm's kube-apiserver Pod manifest now includes the following flags by default "--service-account-key-file", "--service-account-signing-key-file", "--service-account-issuer". ([kubernetes/kubernetes93258](https://github.com/kubernetes/kubernetes/pull/93258), [zshihang](https://github.com/zshihang)) [SIG API Machinery, Auth, Cluster Lifecycle, Storage and Testing]
- Certain fields on Service objects will be automatically cleared when changing the service's `type` to a mode that does not need those fields. For example, changing from type=LoadBalancer to type=ClusterIP will clear the NodePort assignments, rather than forcing the user to clear them. ([kubernetes/kubernetes95196](https://github.com/kubernetes/kubernetes/pull/95196), [thockin](https://github.com/thockin)) [SIG API Machinery, Apps, Network and Testing]
- Services will now have a `clusterIPs` field to go with `clusterIP`. `clusterIPs[0]` is a synonym for `clusterIP` and will be synchronized on create and update operations. ([kubernetes/kubernetes95894](https://github.com/kubernetes/kubernetes/pull/95894), [thockin](https://github.com/thockin)) [SIG Network]
- Add dual-stack Services (alpha). This is a BREAKING CHANGE to an alpha API.
It changes the dual-stack API wrt Service from a single ipFamily field to 3
fields: ipFamilyPolicy (SingleStack, PreferDualStack, RequireDualStack),
ipFamilies (a list of families assigned), and clusterIPs (inclusive of
clusterIP). Most users do not need to set anything at all, defaulting will
handle it for them. Services are single-stack unless the user asks for
dual-stack. This is all gated by the "IPv6DualStack" feature gate. ([kubernetes/kubernetes91824](https://github.com/kubernetes/kubernetes/pull/91824), [khenidak](https://github.com/khenidak)) [SIG API Machinery, Apps, CLI, Network, Node, Scheduling and Testing]
- Introduces a metric source for HPAs which allows scaling based on container resource usage. ([kubernetes/kubernetes90691](https://github.com/kubernetes/kubernetes/pull/90691), [arjunrn](https://github.com/arjunrn)) [SIG API Machinery, Apps, Autoscaling and CLI]
- New parameter `defaultingType` for `PodTopologySpread` plugin allows to use k8s defined or user-provided default constraints ([kubernetes/kubernetes95048](https://github.com/kubernetes/kubernetes/pull/95048), [alculquicondor](https://github.com/alculquicondor)) [SIG Scheduling]
- GPU metrics provided by kubelet are now disabled by default ([kubernetes/kubernetes95184](https://github.com/kubernetes/kubernetes/pull/95184), [RenaudWasTaken](https://github.com/RenaudWasTaken)) [SIG Node]
- New parameter `defaultingType` for `PodTopologySpread` plugin allows to use k8s defined or user provided default constraints ([kubernetes/kubernetes95048](https://github.com/kubernetes/kubernetes/pull/95048), [alculquicondor](https://github.com/alculquicondor)) [SIG Scheduling]
- Server Side Apply now treats LabelSelector fields as atomic (meaning the entire selector is managed by a single writer and updated together), since they contain interrelated and inseparable fields that do not merge in intuitive ways. ([kubernetes/kubernetes93901](https://github.com/kubernetes/kubernetes/pull/93901), [jpbetz](https://github.com/jpbetz)) [SIG API Machinery, Auth, CLI, Cloud Provider, Cluster Lifecycle, Instrumentation, Network, Node, Storage and Testing]
- Status of v1beta1 CRDs without "preserveUnknownFields:false" will show violation "spec.preserveUnknownFields: Invalid value: true: must be false" ([kubernetes/kubernetes93078](https://github.com/kubernetes/kubernetes/pull/93078), [vareti](https://github.com/vareti)) [SIG API Machinery]
- A new `nofuzz` go build tag now disables gofuzz support. Release binaries enable this. ([kubernetes/kubernetes92491](https://github.com/kubernetes/kubernetes/pull/92491), [BenTheElder](https://github.com/BenTheElder)) [SIG API Machinery]
- A new alpha-level field, `SupportsFsGroup`, has been introduced for CSIDrivers to allow them to specify whether they support volume ownership and permission modifications. The `CSIVolumeSupportFSGroup` feature gate must be enabled to allow this field to be used. ([kubernetes/kubernetes92001](https://github.com/kubernetes/kubernetes/pull/92001), [huffmanca](https://github.com/huffmanca)) [SIG API Machinery, CLI and Storage]
- Added pod version skew strategy for seccomp profile to synchronize the deprecated annotations with the new API Server fields. Please see the corresponding section [in the KEP](https://github.com/kubernetes/enhancements/blob/master/keps/sig-node/135-seccomp/README.md#version-skew-strategy) for more detailed explanations. ([kubernetes/kubernetes91408](https://github.com/kubernetes/kubernetes/pull/91408), [saschagrunert](https://github.com/saschagrunert)) [SIG Apps, Auth, CLI and Node]
- Adds the ability to disable Accelerator/GPU metrics collected by Kubelet ([kubernetes/kubernetes91930](https://github.com/kubernetes/kubernetes/pull/91930), [RenaudWasTaken](https://github.com/RenaudWasTaken)) [SIG Node]
- Custom Endpoints are now mirrored to EndpointSlices by a new EndpointSliceMirroring controller. ([kubernetes/kubernetes91637](https://github.com/kubernetes/kubernetes/pull/91637), [robscott](https://github.com/robscott)) [SIG API Machinery, Apps, Auth, Cloud Provider, Instrumentation, Network and Testing]
- External facing API podresources is now available under k8s.io/kubelet/pkg/apis/ ([kubernetes/kubernetes92632](https://github.com/kubernetes/kubernetes/pull/92632), [RenaudWasTaken](https://github.com/RenaudWasTaken)) [SIG Node and Testing]
- Fix conversions for custom metrics. ([kubernetes/kubernetes94481](https://github.com/kubernetes/kubernetes/pull/94481), [wojtek-t](https://github.com/wojtek-t)) [SIG API Machinery and Instrumentation]
- Generic ephemeral volumes, a new alpha feature under the `GenericEphemeralVolume` feature gate, provide a more flexible alternative to `EmptyDir` volumes: as with `EmptyDir`, volumes are created and deleted for each pod automatically by Kubernetes. But because the normal provisioning process is used (`PersistentVolumeClaim`), storage can be provided by third-party storage vendors and all of the usual volume features work. Volumes don't need to be empty; for example, restoring from snapshot is supported. ([kubernetes/kubernetes92784](https://github.com/kubernetes/kubernetes/pull/92784), [pohly](https://github.com/pohly)) [SIG API Machinery, Apps, Auth, CLI, Instrumentation, Node, Scheduling, Storage and Testing]
- Kube-controller-manager: volume plugins can be restricted from contacting local and loopback addresses by setting `--volume-host-allow-local-loopback=false`, or from contacting specific CIDR ranges by setting `--volume-host-cidr-denylist` (for example, `--volume-host-cidr-denylist=127.0.0.1/28,feed::/16`) ([kubernetes/kubernetes91785](https://github.com/kubernetes/kubernetes/pull/91785), [mattcary](https://github.com/mattcary)) [SIG API Machinery, Apps, Auth, CLI, Network, Node, Storage and Testing]
- Kubernetes is now built with golang 1.15.0-rc.1.
- The deprecated, legacy behavior of treating the CommonName field on X.509 serving certificates as a host name when no Subject Alternative Names are present is now disabled by default. It can be temporarily re-enabled by adding the value x509ignoreCN=0 to the GODEBUG environment variable. ([kubernetes/kubernetes93264](https://github.com/kubernetes/kubernetes/pull/93264), [justaugustus](https://github.com/justaugustus)) [SIG API Machinery, Auth, CLI, Cloud Provider, Cluster Lifecycle, Instrumentation, Network, Node, Release, Scalability, Storage and Testing]
- Migrate scheduler, controller-manager and cloud-controller-manager to use LeaseLock ([kubernetes/kubernetes94603](https://github.com/kubernetes/kubernetes/pull/94603), [wojtek-t](https://github.com/wojtek-t)) [SIG API Machinery, Apps, Cloud Provider and Scheduling]
- Modify DNS-1123 error messages to indicate that RFC 1123 is not followed exactly ([kubernetes/kubernetes94182](https://github.com/kubernetes/kubernetes/pull/94182), [mattfenwick](https://github.com/mattfenwick)) [SIG API Machinery, Apps, Auth, Network and Node]
- The ServiceAccountIssuerDiscovery feature gate is now Beta and enabled by default. ([kubernetes/kubernetes91921](https://github.com/kubernetes/kubernetes/pull/91921), [mtaufen](https://github.com/mtaufen)) [SIG Auth]
- The kube-controller-manager managed signers can now have distinct signing certificates and keys. See the help about `--cluster-signing-[signer-name]-{cert,key}-file`. `--cluster-signing-{cert,key}-file` is still the default. ([kubernetes/kubernetes90822](https://github.com/kubernetes/kubernetes/pull/90822), [deads2k](https://github.com/deads2k)) [SIG API Machinery, Apps and Auth]
- When creating a networking.k8s.io/v1 Ingress API object, `spec.tls[*].secretName` values are required to pass validation rules for Secret API object names. ([kubernetes/kubernetes93929](https://github.com/kubernetes/kubernetes/pull/93929), [liggitt](https://github.com/liggitt)) [SIG Network]
- WinOverlay feature graduated to beta ([kubernetes/kubernetes94807](https://github.com/kubernetes/kubernetes/pull/94807), [ksubrmnn](https://github.com/ksubrmnn)) [SIG Windows]

Bug Fix
- Type checking in `Client.serialize_body()` was made more restrictive and robust. ([kubernetes-client/python-base241](https://github.com/kubernetes-client/python-base/pull/241), [piglei](https://github.com/piglei))

Feature
- Support Proxy Authentication in websocket client(stream/ws_client) like REST client. ([kubernetes-client/python-base256](https://github.com/kubernetes-client/python-base/pull/256), [itaru2622](https://github.com/itaru2622))
- Support for the dryRun parameter has been added to the dynamic client. ([kubernetes-client/python-base247](https://github.com/kubernetes-client/python-base/pull/247), [gravesm](https://github.com/gravesm))

API Change
- We have added a new Priority & Fairness rule that exempts all probes (/readyz, /healthz, /livez) to prevent
restarting of "healthy" kube-apiserver instance(s) by kubelet. ([kubernetes/kubernetes101113](https://github.com/kubernetes/kubernetes/pull/101113), [tkashem](https://github.com/tkashem)) [SIG API Machinery]
- Fixes using server-side apply with APIService resources ([kubernetes/kubernetes100713](https://github.com/kubernetes/kubernetes/pull/100713), [kevindelgado](https://github.com/kevindelgado)) [SIG API Machinery, Apps, Scheduling and Testing]
- Regenerate protobuf code to fix CVE-2021-3121 ([kubernetes/kubernetes100515](https://github.com/kubernetes/kubernetes/pull/100515), [joelsmith](https://github.com/joelsmith)) [SIG API Machinery, Auth, CLI, Cloud Provider, Cluster Lifecycle, Instrumentation, Node and Storage]
- Kubernetes is now built using go1.15.8 ([kubernetes/kubernetes99093](https://github.com/kubernetes/kubernetes/pull/99093), [cpanato](https://github.com/cpanato)) [SIG Cloud Provider, Instrumentation, Release and Testing]
- Fix conversions for custom metrics. ([kubernetes/kubernetes94654](https://github.com/kubernetes/kubernetes/pull/94654), [wojtek-t](https://github.com/wojtek-t)) [SIG Instrumentation]
- A new alpha-level field, `SupportsFsGroup`, has been introduced for CSIDrivers to allow them to specify whether they support volume ownership and permission modifications. The `CSIVolumeSupportFSGroup` feature gate must be enabled to allow this field to be used. ([kubernetes/kubernetes92001](https://github.com/kubernetes/kubernetes/pull/92001), [huffmanca](https://github.com/huffmanca)) [SIG API Machinery, CLI and Storage]
- Added pod version skew strategy for seccomp profile to synchronize the deprecated annotations with the new API Server fields. Please see the corresponding section [in the KEP](https://github.com/kubernetes/enhancements/blob/master/keps/sig-node/135-seccomp/README.md#version-skew-strategy) for more detailed explanations. ([kubernetes/kubernetes91408](https://github.com/kubernetes/kubernetes/pull/91408), [saschagrunert](https://github.com/saschagrunert)) [SIG Apps, Auth, CLI and Node]
- Adds the ability to disable Accelerator/GPU metrics collected by Kubelet ([kubernetes/kubernetes91930](https://github.com/kubernetes/kubernetes/pull/91930), [RenaudWasTaken](https://github.com/RenaudWasTaken)) [SIG Node]
- Admission webhooks can now return warning messages that are surfaced to API clients, using the `.response.warnings` field in the admission review response. ([kubernetes/kubernetes92667](https://github.com/kubernetes/kubernetes/pull/92667), [liggitt](https://github.com/liggitt)) [SIG API Machinery and Testing]
- CertificateSigningRequest API conditions were updated:
- a `status` field was added; this field defaults to `True`, and may only be set to `True` for `Approved`, `Denied`, and `Failed` conditions
- a `lastTransitionTime` field was added
- a `Failed` condition type was added to allow signers to indicate permanent failure; this condition can be added via the `certificatesigningrequests/status` subresource.
- `Approved` and `Denied` conditions are mutually exclusive
- `Approved`, `Denied`, and `Failed` conditions can no longer be removed from a CSR ([kubernetes/kubernetes90191](https://github.com/kubernetes/kubernetes/pull/90191), [liggitt](https://github.com/liggitt)) [SIG API Machinery, Apps, Auth, CLI and Node]
- Cluster admins can now turn off /logs endpoint in kubelet by setting enableSystemLogHandler to false in their kubelet configuration file. enableSystemLogHandler can be set to true only when enableDebuggingHandlers is also set to true. ([kubernetes/kubernetes87273](https://github.com/kubernetes/kubernetes/pull/87273), [SaranBalaji90](https://github.com/SaranBalaji90)) [SIG Node]
- Custom Endpoints are now mirrored to EndpointSlices by a new EndpointSliceMirroring controller. ([kubernetes/kubernetes91637](https://github.com/kubernetes/kubernetes/pull/91637), [robscott](https://github.com/robscott)) [SIG API Machinery, Apps, Auth, Cloud Provider, Instrumentation, Network and Testing]
- CustomResourceDefinitions added support for marking versions as deprecated by setting `spec.versions[*].deprecated` to `true`, and for optionally overriding the default deprecation warning with a `spec.versions[*].deprecationWarning` field. ([kubernetes/kubernetes92329](https://github.com/kubernetes/kubernetes/pull/92329), [liggitt](https://github.com/liggitt)) [SIG API Machinery]
- EnvVarSource api doc bug fixes ([kubernetes/kubernetes91194](https://github.com/kubernetes/kubernetes/pull/91194), [wawa0210](https://github.com/wawa0210)) [SIG Apps]
- Fix bug in reflector that couldn't recover from "Too large resource version" errors ([kubernetes/kubernetes92537](https://github.com/kubernetes/kubernetes/pull/92537), [wojtek-t](https://github.com/wojtek-t)) [SIG API Machinery]
- Fixed: log timestamps now include trailing zeros to maintain a fixed width ([kubernetes/kubernetes91207](https://github.com/kubernetes/kubernetes/pull/91207), [iamchuckss](https://github.com/iamchuckss)) [SIG Apps and Node]
- Generic ephemeral volumes, a new alpha feature under the `GenericEphemeralVolume` feature gate, provide a more flexible alternative to `EmptyDir` volumes: as with `EmptyDir`, volumes are created and deleted for each pod automatically by Kubernetes. But because the normal provisioning process is used (`PersistentVolumeClaim`), storage can be provided by third-party storage vendors and all of the usual volume features work. Volumes don't need to be empt; for example, restoring from snapshot is supported. ([kubernetes/kubernetes92784](https://github.com/kubernetes/kubernetes/pull/92784), [pohly](https://github.com/pohly)) [SIG API Machinery, Apps, Auth, CLI, Instrumentation, Node, Scheduling, Storage and Testing]
- Go1.14.4 is now the minimum version required for building Kubernetes ([kubernetes/kubernetes92438](https://github.com/kubernetes/kubernetes/pull/92438), [liggitt](https://github.com/liggitt)) [SIG API Machinery, Auth, CLI, Cloud Provider, Cluster Lifecycle, Instrumentation, Network, Node, Release, Storage and Testing]
- Hide managedFields from kubectl edit command ([kubernetes/kubernetes91946](https://github.com/kubernetes/kubernetes/pull/91946), [soltysh](https://github.com/soltysh)) [SIG CLI]
- K8s.io/apimachinery - scheme.Convert() now uses only explicitly registered conversions - default reflection based conversion is no longer available. `+k8s:conversion-gen` tags can be used with the `k8s.io/code-generator` component to generate conversions. ([kubernetes/kubernetes90018](https://github.com/kubernetes/kubernetes/pull/90018), [wojtek-t](https://github.com/wojtek-t)) [SIG API Machinery, Apps and Testing]
- Kube-proxy: add `--bind-address-hard-fail` flag to treat failure to bind to a port as fatal ([kubernetes/kubernetes89350](https://github.com/kubernetes/kubernetes/pull/89350), [SataQiu](https://github.com/SataQiu)) [SIG Cluster Lifecycle and Network]
- Kubebuilder validation tags are set on metav1.Condition for CRD generation ([kubernetes/kubernetes92660](https://github.com/kubernetes/kubernetes/pull/92660), [damemi](https://github.com/damemi)) [SIG API Machinery]
- Kubelet's --runonce option is now also available in Kubelet's config file as `runOnce`. ([kubernetes/kubernetes89128](https://github.com/kubernetes/kubernetes/pull/89128), [vincent178](https://github.com/vincent178)) [SIG Node]
- Kubelet: add '--logging-format' flag to support structured logging ([kubernetes/kubernetes91532](https://github.com/kubernetes/kubernetes/pull/91532), [afrouzMashaykhi](https://github.com/afrouzMashaykhi)) [SIG API Machinery, Cluster Lifecycle, Instrumentation and Node]
- Kubernetes is now built with golang 1.15.0-rc.1.
- The deprecated, legacy behavior of treating the CommonName field on X.509 serving certificates as a host name when no Subject Alternative Names are present is now disabled by default. It can be temporarily re-enabled by adding the value x509ignoreCN=0 to the GODEBUG environment variable. ([kubernetes/kubernetes93264](https://github.com/kubernetes/kubernetes/pull/93264), [justaugustus](https://github.com/justaugustus)) [SIG API Machinery, Auth, CLI, Cloud Provider, Cluster Lifecycle, Instrumentation, Network, Node, Release, Scalability, Storage and Testing]
- Promote Immutable Secrets/ConfigMaps feature to Beta and enable the feature by default.
This allows to set `Immutable` field in Secrets or ConfigMap object to mark their contents as immutable. ([kubernetes/kubernetes89594](https://github.com/kubernetes/kubernetes/pull/89594), [wojtek-t](https://github.com/wojtek-t)) [SIG Apps and Testing]
- Remove `BindTimeoutSeconds` from schedule configuration `KubeSchedulerConfiguration` ([kubernetes/kubernetes91580](https://github.com/kubernetes/kubernetes/pull/91580), [cofyc](https://github.com/cofyc)) [SIG Scheduling and Testing]
- Remove kubescheduler.config.k8s.io/v1alpha1 ([kubernetes/kubernetes89298](https://github.com/kubernetes/kubernetes/pull/89298), [gavinfish](https://github.com/gavinfish)) [SIG Scheduling]
- Reserve plugins that fail to reserve will trigger the unreserve extension point ([kubernetes/kubernetes92391](https://github.com/kubernetes/kubernetes/pull/92391), [adtac](https://github.com/adtac)) [SIG Scheduling and Testing]
- Resolve regression in `metadata.managedFields` handling in update/patch requests submitted by older API clients ([kubernetes/kubernetes91748](https://github.com/kubernetes/kubernetes/pull/91748), [apelisse](https://github.com/apelisse))
- Scheduler: optionally check for available storage capacity before scheduling pods which have unbound volumes (alpha feature with the new `CSIStorageCapacity` feature gate, only works for CSI drivers and depends on support for the feature in a CSI driver deployment) ([kubernetes/kubernetes92387](https://github.com/kubernetes/kubernetes/pull/92387), [pohly](https://github.com/pohly)) [SIG API Machinery, Apps, Auth, Scheduling, Storage and Testing]
- Seccomp support has graduated to GA. A new `seccompProfile` field is added to pod and container securityContext objects. Support for `seccomp.security.alpha.kubernetes.io/pod` and `container.seccomp.security.alpha.kubernetes.io/...` annotations is deprecated, and will be removed in v1.22. ([kubernetes/kubernetes91381](https://github.com/kubernetes/kubernetes/pull/91381), [pjbgf](https://github.com/pjbgf)) [SIG Apps, Auth, Node, Release, Scheduling and Testing]
- ServiceAppProtocol feature gate is now beta and enabled by default, adding new AppProtocol field to Services and Endpoints. ([kubernetes/kubernetes90023](https://github.com/kubernetes/kubernetes/pull/90023), [robscott](https://github.com/robscott)) [SIG Apps and Network]
- SetHostnameAsFQDN is a new field in PodSpec. When set to true, the fully
qualified domain name (FQDN) of a Pod is set as hostname of its containers.
In Linux containers, this means setting the FQDN in the hostname field of the
kernel (the nodename field of struct utsname). In Windows containers, this
means setting the this means setting the registry value of hostname for the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters to FQDN.
If a pod does not have FQDN, this has no effect. ([kubernetes/kubernetes91699](https://github.com/kubernetes/kubernetes/pull/91699), [javidiaz](https://github.com/javidiaz)) [SIG Apps, Network, Node and Testing]
- The CertificateSigningRequest API is promoted to certificates.k8s.io/v1 with the following changes:
- `spec.signerName` is now required, and requests for `kubernetes.io/legacy-unknown` are not allowed to be created via the `certificates.k8s.io/v1` API
- `spec.usages` is now required, may not contain duplicate values, and must only contain known usages
- `status.conditions` may not contain duplicate types
- `status.conditions[*].status` is now required
- `status.certificate` must be PEM-encoded, and contain only CERTIFICATE blocks ([kubernetes/kubernetes91685](https://github.com/kubernetes/kubernetes/pull/91685), [liggitt](https://github.com/liggitt)) [SIG API Machinery, Architecture, Auth, CLI and Testing]
- The HugePageStorageMediumSize feature gate is now on by default allowing usage of multiple sizes huge page resources on a container level. ([kubernetes/kubernetes90592](https://github.com/kubernetes/kubernetes/pull/90592), [bart0sh](https://github.com/bart0sh)) [SIG Node]
- The Kubelet's --node-status-max-images option is now available via the Kubelet config file field nodeStatusMaxImage ([kubernetes/kubernetes91275](https://github.com/kubernetes/kubernetes/pull/91275), [knabben](https://github.com/knabben)) [SIG Node]
- The Kubelet's --seccomp-profile-root option is now marked as deprecated. ([kubernetes/kubernetes91182](https://github.com/kubernetes/kubernetes/pull/91182), [knabben](https://github.com/knabben)) [SIG Node]
- The Kubelet's `--bootstrap-checkpoint-path` option is now removed. ([kubernetes/kubernetes91577](https://github.com/kubernetes/kubernetes/pull/91577), [knabben](https://github.com/knabben)) [SIG Apps and Node]
- The Kubelet's `--cloud-provider` and `--cloud-config` options are now marked as deprecated. ([kubernetes/kubernetes90408](https://github.com/kubernetes/kubernetes/pull/90408), [knabben](https://github.com/knabben)) [SIG Cloud Provider and Node]
- The Kubelet's `--enable-server` and `--provider-id` option is now available via the Kubelet config file field `enableServer` and `providerID` respectively. ([kubernetes/kubernetes90494](https://github.com/kubernetes/kubernetes/pull/90494), [knabben](https://github.com/knabben)) [SIG Node]
- The Kubelet's `--kernel-memcg-notification` option is now available via the Kubelet config file field kernelMemcgNotification ([kubernetes/kubernetes91863](https://github.com/kubernetes/kubernetes/pull/91863), [knabben](https://github.com/knabben)) [SIG Cloud Provider, Node and Testing]
- The Kubelet's `--really-crash-for-testing` and `--chaos-chance` options are now marked as deprecated. ([kubernetes/kubernetes90499](https://github.com/kubernetes/kubernetes/pull/90499), [knabben](https://github.com/knabben)) [SIG Node]
- The Kubelet's `--volume-plugin-dir` option is now available via the Kubelet config file field `VolumePluginDir`. ([kubernetes/kubernetes88480](https://github.com/kubernetes/kubernetes/pull/88480), [savitharaghunathan](https://github.com/savitharaghunathan)) [SIG Node]
- The `DefaultIngressClass` feature is now GA. The `--feature-gate` parameter will be removed in 1.20. ([kubernetes/kubernetes91957](https://github.com/kubernetes/kubernetes/pull/91957), [cmluciano](https://github.com/cmluciano)) [SIG API Machinery, Apps, Network and Testing]
- The alpha `DynamicAuditing` feature gate and `auditregistration.k8s.io/v1alpha1` API have been removed and are no longer supported. ([kubernetes/kubernetes91502](https://github.com/kubernetes/kubernetes/pull/91502), [deads2k](https://github.com/deads2k)) [SIG API Machinery, Auth and Testing]
- The kube-controller-manager managed signers can now have distinct signing certificates and keys. See the help about `--cluster-signing-[signer-name]-{cert,key}-file`. `--cluster-signing-{cert,key}-file` is still the default. ([kubernetes/kubernetes90822](https://github.com/kubernetes/kubernetes/pull/90822), [deads2k](https://github.com/deads2k)) [SIG API Machinery, Apps and Auth]
- The unused `series.state` field, deprecated since v1.14, is removed from the `events.k8s.io/v1beta1` and `v1` Event types. ([kubernetes/kubernetes90449](https://github.com/kubernetes/kubernetes/pull/90449), [wojtek-t](https://github.com/wojtek-t)) [SIG Apps]
- Unreserve extension point for scheduler plugins is merged into Reserve extension point ([kubernetes/kubernetes92200](https://github.com/kubernetes/kubernetes/pull/92200), [adtac](https://github.com/adtac)) [SIG Scheduling and Testing]
- Update Golang to v1.14.4 ([kubernetes/kubernetes88638](https://github.com/kubernetes/kubernetes/pull/88638), [justaugustus](https://github.com/justaugustus)) [SIG API Machinery, Cloud Provider, Release and Testing]
- Updated the API documentation for Service.Spec.IPFamily to warn that its exact
semantics will probably change before the dual-stack feature goes GA, and users
should look at ClusterIP or Endpoints, not IPFamily, to figure out if an existing
Service is IPv4, IPv6, or dual-stack. ([kubernetes/kubernetes91527](https://github.com/kubernetes/kubernetes/pull/91527), [danwinship](https://github.com/danwinship)) [SIG Apps and Network]
- Users can configure a resource prefix to ignore a group of resources. ([kubernetes/kubernetes88842](https://github.com/kubernetes/kubernetes/pull/88842), [angao](https://github.com/angao)) [SIG Node and Scheduling]
- `Ingress` and `IngressClass` resources have graduated to `networking.k8s.io/v1`. Ingress and IngressClass types in the `extensions/v1beta1` and `networking.k8s.io/v1beta1` API versions are deprecated and will no longer be served in 1.22+. Persisted objects can be accessed via the `networking.k8s.io/v1` API. Notable changes in v1 Ingress objects (v1beta1 field names are unchanged):
- `spec.backend` -> `spec.defaultBackend`
- `serviceName` -> `service.name`
- `servicePort` -> `service.port.name` (for string values)
- `servicePort` -> `service.port.number` (for numeric values)
- `pathType` no longer has a default value in v1; "Exact", "Prefix", or "ImplementationSpecific" must be specified
Other Ingress API updates:
- backends can now be resource or service backends
- `path` is no longer required to be a valid regular expression ([kubernetes/kubernetes89778](https://github.com/kubernetes/kubernetes/pull/89778), [cmluciano](https://github.com/cmluciano)) [SIG API Machinery, Apps, CLI, Network and Testing]
- `NodeResourcesLeastAllocated` and `NodeResourcesMostAllocated` plugins now support customized weight on the CPU and memory. ([kubernetes/kubernetes90544](https://github.com/kubernetes/kubernetes/pull/90544), [chendave](https://github.com/chendave)) [SIG Scheduling]
- `PostFilter` type is added to scheduler component config API on version v1beta1. ([kubernetes/kubernetes91547](https://github.com/kubernetes/kubernetes/pull/91547), [Huang-Wei](https://github.com/Huang-Wei)) [SIG Scheduling]
- `RequestedToCapacityRatioArgs` encoding is now strict ([kubernetes/kubernetes91603](https://github.com/kubernetes/kubernetes/pull/91603), [pancernik](https://github.com/pancernik)) [SIG Scheduling]
- `v1beta1` Scheduler `Extender` encoding is case-sensitive (`v1alpha1`/`v1alpha2` was case-insensitive), its `httpTimeout` field uses duration encoding (for example, one second is specified as `"1s"`), and the `enableHttps` field in `v1alpha1`/`v1alpha2` was renamed to `enableHTTPS`. ([kubernetes/kubernetes91625](https://github.com/kubernetes/kubernetes/pull/91625), [pancernik](https://github.com/pancernik)) [SIG Scheduling]
- Adds the ability to disable Accelerator/GPU metrics collected by Kubelet ([kubernetes/kubernetes91930](https://github.com/kubernetes/kubernetes/pull/91930), [RenaudWasTaken](https://github.com/RenaudWasTaken)) [SIG Node]
- Kubernetes is now built with golang 1.15.0-rc.1.
- The deprecated, legacy behavior of treating the CommonName field on X.509 serving certificates as a host name when no Subject Alternative Names are present is now disabled by default. It can be temporarily re-enabled by adding the value x509ignoreCN=0 to the GODEBUG environment variable. ([kubernetes/kubernetes93264](https://github.com/kubernetes/kubernetes/pull/93264), [justaugustus](https://github.com/justaugustus)) [SIG API Machinery, Auth, CLI, Cloud Provider, Cluster Lifecycle, Instrumentation, Network, Node, Release, Scalability, Storage and Testing]
- A new alpha-level field, `SupportsFsGroup`, has been introduced for CSIDrivers to allow them to specify whether they support volume ownership and permission modifications. The `CSIVolumeSupportFSGroup` feature gate must be enabled to allow this field to be used. ([kubernetes/kubernetes92001](https://github.com/kubernetes/kubernetes/pull/92001), [huffmanca](https://github.com/huffmanca)) [SIG API Machinery, CLI and Storage]
- The kube-controller-manager managed signers can now have distinct signing certificates and keys. See the help about `--cluster-signing-[signer-name]-{cert,key}-file`. `--cluster-signing-{cert,key}-file` is still the default. ([kubernetes/kubernetes90822](https://github.com/kubernetes/kubernetes/pull/90822), [deads2k](https://github.com/deads2k)) [SIG API Machinery, Apps and Auth]
- Added pod version skew strategy for seccomp profile to synchronize the deprecated annotations with the new API Server fields. Please see the corresponding section [in the KEP](https://github.com/kubernetes/enhancements/tree/master/keps/sig-node/135-seccomp#version-skew-strategy) for more detailed explanations. ([kubernetes/kubernetes91408](https://github.com/kubernetes/kubernetes/pull/91408), [saschagrunert](https://github.com/saschagrunert)) [SIG Apps, Auth, CLI and Node]
- Custom Endpoints are now mirrored to EndpointSlices by a new EndpointSliceMirroring controller. ([kubernetes/kubernetes91637](https://github.com/kubernetes/kubernetes/pull/91637), [robscott](https://github.com/robscott)) [SIG API Machinery, Apps, Auth, Cloud Provider, Instrumentation, Network and Testing]
- Generic ephemeral volumes, a new alpha feature under the `GenericEphemeralVolume` feature gate, provide a more flexible alternative to `EmptyDir` volumes: as with `EmptyDir`, volumes are created and deleted for each pod automatically by Kubernetes. But because the normal provisioning process is used (`PersistentVolumeClaim`), storage can be provided by third-party storage vendors and all of the usual volume features work. Volumes don't need to be empt; for example, restoring from snapshot is supported. ([kubernetes/kubernetes92784](https://github.com/kubernetes/kubernetes/pull/92784), [pohly](https://github.com/pohly)) [SIG API Machinery, Apps, Auth, CLI, Instrumentation, Node, Scheduling, Storage and Testing]
- Remove `BindTimeoutSeconds` from schedule configuration `KubeSchedulerConfiguration` ([kubernetes/kubernetes91580](https://github.com/kubernetes/kubernetes/pull/91580), [cofyc](https://github.com/cofyc)) [SIG Scheduling and Testing]
- Resolve regression in metadata.managedFields handling in update/patch requests submitted by older API clients ([kubernetes/kubernetes91748](https://github.com/kubernetes/kubernetes/pull/91748), [apelisse](https://github.com/apelisse)) [SIG API Machinery and Testing]
- The CertificateSigningRequest API is promoted to certificates.k8s.io/v1 with the following changes:
- `spec.signerName` is now required, and requests for `kubernetes.io/legacy-unknown` are not allowed to be created via the `certificates.k8s.io/v1` API
- `spec.usages` is now required, may not contain duplicate values, and must only contain known usages
- `status.conditions` may not contain duplicate types
- `status.conditions[*].status` is now required
- `status.certificate` must be PEM-encoded, and contain only CERTIFICATE blocks ([kubernetes/kubernetes91685](https://github.com/kubernetes/kubernetes/pull/91685), [liggitt](https://github.com/liggitt)) [SIG API Machinery, Architecture, Auth, CLI and Testing]
- The Kubelet's `--cloud-provider` and `--cloud-config` options are now marked as deprecated. ([kubernetes/kubernetes90408](https://github.com/kubernetes/kubernetes/pull/90408), [knabben](https://github.com/knabben)) [SIG Cloud Provider and Node]
- CertificateSigningRequest API conditions were updated:
- a `status` field was added; this field defaults to `True`, and may only be set to `True` for `Approved`, `Denied`, and `Failed` conditions
- a `lastTransitionTime` field was added
- a `Failed` condition type was added to allow signers to indicate permanent failure; this condition can be added via the `certificatesigningrequests/status` subresource.
- `Approved` and `Denied` conditions are mutually exclusive
- `Approved`, `Denied`, and `Failed` conditions can no longer be removed from a CSR ([kubernetes/kubernetes90191](https://github.com/kubernetes/kubernetes/pull/90191), [liggitt](https://github.com/liggitt)) [SIG API Machinery, Apps, Auth, CLI and Node]
- EnvVarSource api doc bug fixes ([kubernetes/kubernetes91194](https://github.com/kubernetes/kubernetes/pull/91194), [wawa0210](https://github.com/wawa0210)) [SIG Apps]
- Fixed: log timestamps now include trailing zeros to maintain a fixed width ([kubernetes/kubernetes91207](https://github.com/kubernetes/kubernetes/pull/91207), [iamchuckss](https://github.com/iamchuckss)) [SIG Apps and Node]
- The Kubelet's --node-status-max-images option is now available via the Kubelet config file field nodeStatusMaxImage ([kubernetes/kubernetes91275](https://github.com/kubernetes/kubernetes/pull/91275), [knabben](https://github.com/knabben)) [SIG Node]
- The Kubelet's --seccomp-profile-root option is now available via the Kubelet config file field seccompProfileRoot. ([kubernetes/kubernetes91182](https://github.com/kubernetes/kubernetes/pull/91182), [knabben](https://github.com/knabben)) [SIG Node]
- The Kubelet's `--enable-server` and `--provider-id` option is now available via the Kubelet config file field `enableServer` and `providerID` respectively. ([kubernetes/kubernetes90494](https://github.com/kubernetes/kubernetes/pull/90494), [knabben](https://github.com/knabben)) [SIG Node]
- The Kubelet's `--really-crash-for-testing` and `--chaos-chance` options are now marked as deprecated. ([kubernetes/kubernetes90499](https://github.com/kubernetes/kubernetes/pull/90499), [knabben](https://github.com/knabben)) [SIG Node]
- The alpha `DynamicAuditing` feature gate and `auditregistration.k8s.io/v1alpha1` API have been removed and are no longer supported. ([kubernetes/kubernetes91502](https://github.com/kubernetes/kubernetes/pull/91502), [deads2k](https://github.com/deads2k)) [SIG API Machinery, Auth and Testing]
- `NodeResourcesLeastAllocated` and `NodeResourcesMostAllocated` plugins now support customized weight on the CPU and memory. ([kubernetes/kubernetes90544](https://github.com/kubernetes/kubernetes/pull/90544), [chendave](https://github.com/chendave)) [SIG Scheduling]
- `PostFilter` type is added to scheduler component config API on version v1beta1. ([kubernetes/kubernetes91547](https://github.com/kubernetes/kubernetes/pull/91547), [Huang-Wei](https://github.com/Huang-Wei)) [SIG Scheduling]
- `kubescheduler.config.k8s.io` is now beta ([kubernetes/kubernetes91420](https://github.com/kubernetes/kubernetes/pull/91420), [pancernik](https://github.com/pancernik)) [SIG Scheduling]
- EnvVarSource api doc bug fixes ([kubernetes/kubernetes91194](https://github.com/kubernetes/kubernetes/pull/91194), [wawa0210](https://github.com/wawa0210)) [SIG Apps]
- The Kubelet's `--really-crash-for-testing` and `--chaos-chance` options are now marked as deprecated. ([kubernetes/kubernetes90499](https://github.com/kubernetes/kubernetes/pull/90499), [knabben](https://github.com/knabben)) [SIG Node]
- `NodeResourcesLeastAllocated` and `NodeResourcesMostAllocated` plugins now support customized weight on the CPU and memory. ([kubernetes/kubernetes90544](https://github.com/kubernetes/kubernetes/pull/90544), [chendave](https://github.com/chendave)) [SIG Scheduling]
- K8s.io/apimachinery - scheme.Convert() now uses only explicitly registered conversions - default reflection based conversion is no longer available. `+k8s:conversion-gen` tags can be used with the `k8s.io/code-generator` component to generate conversions. ([kubernetes/kubernetes90018](https://github.com/kubernetes/kubernetes/pull/90018), [wojtek-t](https://github.com/wojtek-t)) [SIG API Machinery, Apps and Testing]
- Kubelet's --runonce option is now also available in Kubelet's config file as `runOnce`. ([kubernetes/kubernetes89128](https://github.com/kubernetes/kubernetes/pull/89128), [vincent178](https://github.com/vincent178)) [SIG Node]
- Promote Immutable Secrets/ConfigMaps feature to Beta and enable the feature by default.
This allows to set `Immutable` field in Secrets or ConfigMap object to mark their contents as immutable. ([kubernetes/kubernetes89594](https://github.com/kubernetes/kubernetes/pull/89594), [wojtek-t](https://github.com/wojtek-t)) [SIG Apps and Testing]
- The unused `series.state` field, deprecated since v1.14, is removed from the `events.k8s.io/v1beta1` and `v1` Event types. ([kubernetes/kubernetes90449](https://github.com/kubernetes/kubernetes/pull/90449), [wojtek-t](https://github.com/wojtek-t)) [SIG Apps]
- Kube-proxy: add `--bind-address-hard-fail` flag to treat failure to bind to a port as fatal ([kubernetes/kubernetes89350](https://github.com/kubernetes/kubernetes/pull/89350), [SataQiu](https://github.com/SataQiu)) [SIG Cluster Lifecycle and Network]
- Remove kubescheduler.config.k8s.io/v1alpha1 ([kubernetes/kubernetes89298](https://github.com/kubernetes/kubernetes/pull/89298), [gavinfish](https://github.com/gavinfish)) [SIG Scheduling]
- ServiceAppProtocol feature gate is now beta and enabled by default, adding new AppProtocol field to Services and Endpoints. ([kubernetes/kubernetes90023](https://github.com/kubernetes/kubernetes/pull/90023), [robscott](https://github.com/robscott)) [SIG Apps and Network]
- The Kubelet's `--volume-plugin-dir` option is now available via the Kubelet config file field `VolumePluginDir`. ([kubernetes/kubernetes88480](https://github.com/kubernetes/kubernetes/pull/88480), [savitharaghunathan](https://github.com/savitharaghunathan)) [SIG Node]
- A new IngressClass resource has been added to enable better Ingress configuration. ([kubernetes/kubernetes88509](https://github.com/kubernetes/kubernetes/pull/88509), [robscott](https://github.com/robscott)) [SIG API Machinery, Apps, CLI, Network, Node and Testing]
- API additions to apiserver types ([kubernetes/kubernetes87179](https://github.com/kubernetes/kubernetes/pull/87179), [Jefftree](https://github.com/Jefftree)) [SIG API Machinery, Cloud Provider and Cluster Lifecycle]
- Add Scheduling Profiles to kubescheduler.config.k8s.io/v1alpha2 ([kubernetes/kubernetes88087](https://github.com/kubernetes/kubernetes/pull/88087), [alculquicondor](https://github.com/alculquicondor)) [SIG Scheduling and Testing]
- Added GenericPVCDataSource feature gate to enable using arbitrary custom resources as the data source for a PVC. ([kubernetes/kubernetes88636](https://github.com/kubernetes/kubernetes/pull/88636), [bswartz](https://github.com/bswartz)) [SIG Apps and Storage]
- Added support for multiple sizes huge pages on a container level ([kubernetes/kubernetes84051](https://github.com/kubernetes/kubernetes/pull/84051), [bart0sh](https://github.com/bart0sh)) [SIG Apps, Node and Storage]
- Allow user to specify fsgroup permission change policy for pods ([kubernetes/kubernetes88488](https://github.com/kubernetes/kubernetes/pull/88488), [gnufied](https://github.com/gnufied)) [SIG Apps and Storage]
- AppProtocol is a new field on Service and Endpoints resources, enabled with the ServiceAppProtocol feature gate. ([kubernetes/kubernetes88503](https://github.com/kubernetes/kubernetes/pull/88503), [robscott](https://github.com/robscott)) [SIG Apps and Network]
- BlockVolume and CSIBlockVolume features are now GA. ([kubernetes/kubernetes88673](https://github.com/kubernetes/kubernetes/pull/88673), [jsafrane](https://github.com/jsafrane)) [SIG Apps, Node and Storage]
- Consumers of the 'certificatesigningrequests/approval' API must now grant permission to 'approve' CSRs for the 'signerName' specified on the CSR. More information on the new signerName field can be found at https://github.com/kubernetes/enhancements/blob/master/keps/sig-auth/1513-certificate-signing-request/README.md/#signers ([kubernetes/kubernetes88246](https://github.com/kubernetes/kubernetes/pull/88246), [munnerz](https://github.com/munnerz)) [SIG API Machinery, Apps, Auth, CLI, Node and Testing]
- CustomResourceDefinition schemas that use `x-kubernetes-list-map-keys` to specify properties that uniquely identify list items must make those properties required or have a default value, to ensure those properties are present for all list items. See https://kubernetes.io/docs/reference/using-api/api-concepts/#merge-strategy for details. ([kubernetes/kubernetes88076](https://github.com/kubernetes/kubernetes/pull/88076), [eloyekunle](https://github.com/eloyekunle)) [SIG API Machinery and Testing]
- Fixed missing validation of uniqueness of list items in lists with `x-kubernetes-list-type: map` or `x-kubernetes-list-type: set` in CustomResources. ([kubernetes/kubernetes84920](https://github.com/kubernetes/kubernetes/pull/84920), [sttts](https://github.com/sttts)) [SIG API Machinery]
- Fixes a regression with clients prior to 1.15 not being able to update podIP in pod status, or podCIDR in node spec, against >= 1.16 API servers ([kubernetes/kubernetes88505](https://github.com/kubernetes/kubernetes/pull/88505), [liggitt](https://github.com/liggitt)) [SIG Apps and Network]
- Ingress: Add Exact and Prefix matching to Ingress PathTypes ([kubernetes/kubernetes88587](https://github.com/kubernetes/kubernetes/pull/88587), [cmluciano](https://github.com/cmluciano)) [SIG Apps, Cluster Lifecycle and Network]
- Ingress: Add alternate backends via TypedLocalObjectReference ([kubernetes/kubernetes88775](https://github.com/kubernetes/kubernetes/pull/88775), [cmluciano](https://github.com/cmluciano)) [SIG Apps and Network]
- Ingress: allow wildcard hosts in IngressRule ([kubernetes/kubernetes88858](https://github.com/kubernetes/kubernetes/pull/88858), [cmluciano](https://github.com/cmluciano)) [SIG Network]
- Introduces optional --detect-local flag to kube-proxy.
Currently the only supported value is "cluster-cidr",
which is the default if not specified. ([kubernetes/kubernetes87748](https://github.com/kubernetes/kubernetes/pull/87748), [satyasm](https://github.com/satyasm)) [SIG Cluster Lifecycle, Network and Scheduling]
- Kube-controller-manager and kube-scheduler expose profiling by default to match the kube-apiserver. Use `--profiling=false` to disable. ([kubernetes/kubernetes88663](https://github.com/kubernetes/kubernetes/pull/88663), [deads2k](https://github.com/deads2k)) [SIG API Machinery, Cloud Provider and Scheduling]
- Kube-scheduler can run more than one scheduling profile. Given a pod, the profile is selected by using its `.spec.SchedulerName`. ([kubernetes/kubernetes88285](https://github.com/kubernetes/kubernetes/pull/88285), [alculquicondor](https://github.com/alculquicondor)) [SIG Apps, Scheduling and Testing]
- Move TaintBasedEvictions feature gates to GA ([kubernetes/kubernetes87487](https://github.com/kubernetes/kubernetes/pull/87487), [skilxn-go](https://github.com/skilxn-go)) [SIG API Machinery, Apps, Node, Scheduling and Testing]
- Moving Windows RunAsUserName feature to GA ([kubernetes/kubernetes87790](https://github.com/kubernetes/kubernetes/pull/87790), [marosset](https://github.com/marosset)) [SIG Apps and Windows]
- New flag --endpointslice-updates-batch-period in kube-controller-manager can be used to reduce number of endpointslice updates generated by pod changes. ([kubernetes/kubernetes88745](https://github.com/kubernetes/kubernetes/pull/88745), [mborsz](https://github.com/mborsz)) [SIG API Machinery, Apps and Network]
- New flag `--show-hidden-metrics-for-version` in kubelet can be used to show all hidden metrics that deprecated in the previous minor release. ([kubernetes/kubernetes85282](https://github.com/kubernetes/kubernetes/pull/85282), [serathius](https://github.com/serathius)) [SIG Node]
- Removes ConfigMap as suggestion for IngressClass parameters ([kubernetes/kubernetes89093](https://github.com/kubernetes/kubernetes/pull/89093), [robscott](https://github.com/robscott)) [SIG Network]
- Scheduler Extenders can now be configured in the v1alpha2 component config ([kubernetes/kubernetes88768](https://github.com/kubernetes/kubernetes/pull/88768), [damemi](https://github.com/damemi)) [SIG Release, Scheduling and Testing]
- The apiserver/v1alph1 EgressSelectorConfiguration API is now beta. ([kubernetes/kubernetes88502](https://github.com/kubernetes/kubernetes/pull/88502), [caesarxuchao](https://github.com/caesarxuchao)) [SIG API Machinery]
- The storage.k8s.io/CSIDriver has moved to GA, and is now available for use. ([kubernetes/kubernetes84814](https://github.com/kubernetes/kubernetes/pull/84814), [huffmanca](https://github.com/huffmanca)) [SIG API Machinery, Apps, Auth, Node, Scheduling, Storage and Testing]
- VolumePVCDataSource moves to GA in 1.18 release ([kubernetes/kubernetes88686](https://github.com/kubernetes/kubernetes/pull/88686), [j-griffith](https://github.com/j-griffith)) [SIG Apps, CLI and Cluster Lifecycle]

**Important Information:**

- Python 2 had reached [End of Life](https://www.python.org/doc/sunset-python-2/) on January 1, 2020. The Kubernetes Python Client has dropped support for Python 2 from this release (v18.20.0b1) and will no longer provide support to older clients as per the [Kubernetes support policy](https://kubernetes.io/docs/setup/release/version-skew-policy/#supported-versions).

**Important Information:**

- The Kubernetes Python client versioning scheme has changed. The version numbers used till Kubernetes Python Client v12.y.z lagged behind the actual Kubernetes minor version numbers. From this release, the client is moving a version format `vY.Z.P` where `Y` and `Z` are respectively from the Kubernetes version `v1.Y.Z` and `P` would incremented due to changes on the Python client side itself. Ref: https://github.com/kubernetes-client/python/issues/1244
- Python 2 had reached [End of Life](https://www.python.org/doc/sunset-python-2/) on January 1, 2020. The Kubernetes Python Client has dropped support for Python 2 from this release (v18.0.0) and will no longer provide support to older clients as per the [Kubernetes support policy](https://kubernetes.io/docs/setup/release/version-skew-policy/#supported-versions).

**Deprecations:**
- The following deprecated APIs can no longer be served:
- All resources under `apps/v1beta1` and `apps/v1beta2` - use `apps/v1` instead
- `daemonsets`, `deployments`, `replicasets` resources under `extensions/v1beta1` - use `apps/v1` instead
- `networkpolicies` resources under `extensions/v1beta1` - use `networking.k8s.io/v1` instead
- `podsecuritypolicies` resources under `extensions/v1beta1` - use `policy/v1beta1` instead ([85903](https://github.com/kubernetes/kubernetes/pull/85903), [liggitt](https://github.com/liggitt)) [SIG API Machinery, Apps, Cluster Lifecycle, Instrumentation and Testing]

**New Feature:**
- Support leader election. [kubernetes-client/python-base206](https://github.com/kubernetes-client/python-base/pull/206)

**Bug Fix:**
- Raise exception when an empty config file is passed to load_kube_config. [kubernetes-client/python-base223](https://github.com/kubernetes-client/python-base/pull/223)
- fix: load cache error when CacheDecoder object is not callable. [kubernetes-client/python-base226](https://github.com/kubernetes-client/python-base/pull/226)
- Fix Watch retries with 410 errors. [kubernetes-client/python-base227](https://github.com/kubernetes-client/python-base/pull/227)
- Automatically handles chunked or non-chunked responses. Fix ResponseNotChunked error from watch. [kubernetes-client/python-base231](https://github.com/kubernetes-client/python-base/pull/231)

**API Change:**
- Add allowWatchBookmarks, resoureVersionMatch parameters to custom objects. [kubernetes-client/gen180](https://github.com/kubernetes-client/gen/pull/180)
- Fix bug in reflector that couldn't recover from "Too large resource version" errors ([92537](https://github.com/kubernetes/kubernetes/pull/92537), [wojtek-t](https://github.com/wojtek-t)) [SIG API Machinery]
- Fixed: log timestamps now include trailing zeros to maintain a fixed width ([91207](https://github.com/kubernetes/kubernetes/pull/91207), [iamchuckss](https://github.com/iamchuckss)) [SIG Apps and Node]
- Fixed: log timestamps now include trailing zeros to maintain a fixed width ([91207](https://github.com/kubernetes/kubernetes/pull/91207), [iamchuckss](https://github.com/iamchuckss)) [SIG Apps and Node]
- Resolve regression in metadata.managedFields handling in update/patch requests submitted by older API clients ([92007](https://github.com/kubernetes/kubernetes/pull/92007), [apelisse](https://github.com/apelisse)) [SIG API Machinery and Testing]
- A new IngressClass resource has been added to enable better Ingress configuration. ([88509](https://github.com/kubernetes/kubernetes/pull/88509), [robscott](https://github.com/robscott)) [SIG API Machinery, Apps, CLI, Network, Node and Testing]
- The CSIDriver API has graduated to storage.k8s.io/v1, and is now available for use. ([84814](https://github.com/kubernetes/kubernetes/pull/84814), [huffmanca](https://github.com/huffmanca)) [SIG Storage]
- autoscaling/v2beta2 HorizontalPodAutoscaler added a `spec.behavior` field that allows scale behavior to be configured. Behaviors are specified separately for scaling up and down. In each direction a stabilization window can be specified as well as a list of policies and how to select amongst them. Policies can limit the absolute number of pods added or removed, or the percentage of pods added or removed. ([74525](https://github.com/kubernetes/kubernetes/pull/74525), [gliush](https://github.com/gliush)) [SIG API Machinery, Apps, Autoscaling and CLI]
- Ingress:
- `spec.ingressClassName` replaces the deprecated `kubernetes.io/ingress.class` annotation, and allows associating an Ingress object with a particular controller.
- path definitions added a `pathType` field to allow indicating how the specified path should be matched against incoming requests. Valid values are `Exact`, `Prefix`, and `ImplementationSpecific` ([88587](https://github.com/kubernetes/kubernetes/pull/88587), [cmluciano](https://github.com/cmluciano)) [SIG Apps, Cluster Lifecycle and Network]
- The alpha feature `AnyVolumeDataSource` enables PersistentVolumeClaim objects to use the spec.dataSource field to reference a custom type as a data source ([88636](https://github.com/kubernetes/kubernetes/pull/88636), [bswartz](https://github.com/bswartz)) [SIG Apps and Storage]
- The alpha feature `ConfigurableFSGroupPolicy` enables v1 Pods to specify a spec.securityContext.fsGroupChangePolicy policy to control how file permissions are applied to volumes mounted into the pod. ([88488](https://github.com/kubernetes/kubernetes/pull/88488), [gnufied](https://github.com/gnufied)) [SIG Storage]
- The alpha feature `ServiceAppProtocol` enables setting an `appProtocol` field in ServicePort and EndpointPort definitions. ([88503](https://github.com/kubernetes/kubernetes/pull/88503), [robscott](https://github.com/robscott)) [SIG Apps and Network]
- The alpha feature `ImmutableEphemeralVolumes` enables an `immutable` field in both Secret and ConfigMap objects to mark their contents as immutable. ([86377](https://github.com/kubernetes/kubernetes/pull/86377), [wojtek-t](https://github.com/wojtek-t)) [SIG Apps, CLI and Testing]
- The beta feature `ServerSideApply` enables tracking and managing changed fields for all new objects, which means there will be `managedFields` in `metadata` with the list of managers and their owned fields.
- The alpha feature `ServiceAccountIssuerDiscovery` enables publishing OIDC discovery information and service account token verification keys at `/.well-known/openid-configuration` and `/openid/v1/jwks` endpoints by API servers configured to issue service account tokens. ([80724](https://github.com/kubernetes/kubernetes/pull/80724), [cceckman](https://github.com/cceckman)) [SIG API Machinery, Auth, Cluster Lifecycle and Testing]
- CustomResourceDefinition schemas that use `x-kubernetes-list-map-keys` to specify properties that uniquely identify list items must make those properties required or have a default value, to ensure those properties are present for all list items. See https://kubernetes.io/docs/reference/using-api/api-concepts/#merge-strategy for details. ([88076](https://github.com/kubernetes/kubernetes/pull/88076), [eloyekunle](https://github.com/eloyekunle)) [SIG API Machinery and Testing]
- CustomResourceDefinition schemas that use `x-kubernetes-list-type: map` or `x-kubernetes-list-type: set` now enable validation that the list items in the corresponding custom resources are unique. ([84920](https://github.com/kubernetes/kubernetes/pull/84920), [sttts](https://github.com/sttts)) [SIG API Machinery]


To read the full CHANGELOG visit [here](https://raw.githubusercontent.com/kubernetes/kubernetes/master/CHANGELOG/CHANGELOG-1.18.md).

**Important Information:**

- The Kubernetes Python client versioning scheme has changed. The version numbers used till Kubernetes Python Client v12.y.z lagged behind the actual Kubernetes minor version numbers. From this release, the client is moving a version format `vY.Z.P` where `Y` and `Z` are respectively from the Kubernetes version `v1.Y.Z` and `P` would incremented due to changes on the Python client side itself. Ref: https://github.com/kubernetes-client/python/issues/1244
- Python 2 had reached [End of Life](https://www.python.org/doc/sunset-python-2/) on January 1, 2020. The Kubernetes Python Client will drop support for Python 2 from the next release (v18.0.0) and will no longer provide support to older clients as per the [Kubernetes support policy](https://kubernetes.io/docs/setup/release/version-skew-policy/#supported-versions).


**API Change:**
- Fixed: log timestamps now include trailing zeros to maintain a fixed width ([91207](https://github.com/kubernetes/kubernetes/pull/91207), [iamchuckss](https://github.com/iamchuckss)) [SIG Apps and Node]
- Resolve regression in metadata.managedFields handling in update/patch requests submitted by older API clients ([92008](https://github.com/kubernetes/kubernetes/pull/92008), [apelisse](https://github.com/apelisse)) [SIG API Machinery and Testing]
- Fix bug where sending a status update completely wipes managedFields for some types. ([90032](https://github.com/kubernetes/kubernetes/pull/90032), [apelisse](https://github.com/apelisse)) [SIG API Machinery and Testing]
- Fixes a regression with clients prior to 1.15 not being able to update podIP in pod status, or podCIDR in node spec, against >= 1.16 API servers ([88505](https://github.com/kubernetes/kubernetes/pull/88505), [liggitt](https://github.com/liggitt)) [SIG Apps and Network]
- CustomResourceDefinitions now validate documented API semantics of `x-kubernetes-list-type` and `x-kubernetes-map-type` atomic to reject non-atomic sub-types. ([84722](https://github.com/kubernetes/kubernetes/pull/84722), [sttts](https://github.com/sttts))
- Kube-apiserver: The `AdmissionConfiguration` type accepted by `--admission-control-config-file` has been promoted to `apiserver.config.k8s.io/v1` with no schema changes. ([85098](https://github.com/kubernetes/kubernetes/pull/85098), [liggitt](https://github.com/liggitt))
- Fixed EndpointSlice port name validation to match Endpoint port name validation (allowing port names longer than 15 characters) ([84481](https://github.com/kubernetes/kubernetes/pull/84481), [robscott](https://github.com/robscott))
- CustomResourceDefinitions introduce `x-kubernetes-map-type` annotation as a CRD API extension. Enables this particular validation for server-side apply. ([84113](https://github.com/kubernetes/kubernetes/pull/84113), [enxebre](https://github.com/enxebre))

To read the full CHANGELOG visit [here](https://raw.githubusercontent.com/kubernetes/kubernetes/master/CHANGELOG/CHANGELOG-1.17.md).