- The  performance of Pod affinity/anti-affinity in the scheduler has been improved. ([#67788](https://github.com/kubernetes/kubernetes/pull/67788), [@ahmad-diaa](https://github.com/ahmad-diaa)) Courtesy of SIG Scalability, and SIG Scheduling

([#62695](https://github.com/kubernetes/kubernetes/pull/62695), [@CaoShuFeng](https://github.com/CaoShuFeng))

### IPv4/IPv6 run

IPv4/IPv6 dual-stack has been reimplemented for 1.20 to support dual-stack Services, based on user and community feedback. If your cluster has dual-stack enabled, you can create Services which can use IPv4, IPv6, or both, and you can change this setting for existing Services. Details are available in updated [IPv4/IPv6 dual-stack docs](https://docs.k8s.io/concepts/services-networking/dual-stack/), which cover the nuanced array of options.

pkg log/syslog (netbsd-arm64-cgo), const LOG_UUCP Priority
pkg log/syslog (netbsd-arm64-cgo), const LOG_WARNING = 4
pkg log/syslog (netbsd-arm64-cgo), const LOG_WARNING Priority
pkg log/syslog (netbsd-arm64-cgo), func Dial(string, string, Priority, string) (*Writer, error)
pkg log/syslog (netbsd-arm64-cgo), func NewLogger(Priority, int) (*log.Logger, error)
pkg log/syslog (netbsd-arm64-cgo), func New(Priority, string) (*Writer, error)

* etcd client add dial timeout. ([#61459](https://github.com/kubernetes/kubernetes/pull/61459), [@hzxuzhonghu](https://github.com/hzxuzhonghu))

pkg net/http, type CloseNotifier //deprecated
pkg net/http, type ProtocolError //deprecated
pkg net/http, type Request struct, Cancel //deprecated
pkg net/http, type Transport struct, Dial //deprecated
pkg net/http, type Transport struct, DialTLS //deprecated
pkg net/http, var ErrHeaderTooLong //deprecated
pkg net/http, var ErrMissingContentLength //deprecated
pkg net/http, var ErrShortBody //deprecated

### IPv4/IPv6 Dual-stack Networking graduates to GA

[IPv4/IPv6 dual-stack networking](https://github.com/kubernetes/enhancements/tree/master/keps/sig-network/563-dual-stack) graduates to GA.
Since 1.21, Kubernetes clusters are enabled to support dual-stack networking by default.
In 1.23, the `IPv6DualStack` feature gate is removed.
The use of dual-stack networking is not mandatory.

- [Topology Manager](https://github.com/kubernetes/enhancements/issues/693), a new Kubelet component, aims to co-ordinate resource assignment decisions to provide optimized resource allocations.
- [IPv4/IPv6 dual-stack](https://kubernetes.io/docs/concepts/services-networking/dual-stack) enables the allocation of both IPv4 and IPv6 addresses to Pods and Services.

- Users might specify the `kubectl.kubernetes.io/default-container` annotation in a Pod...

- kube-apiserver: Fixes an issue updating the default ServiceCIDR API object and creating dual-stack Service API objects when `--service-cluster-ip-range` flag passed to kube-apiserver is changed from single-stack to dual-stack. ([#131263](https://github.com/kubernetes/kubernetes/pull/131263), [@aojea](https://github.com/aojea)) [SIG API Machinery, Network and Testing]