and “net.ipv4.tcp_keepalive_probes“ sysctl by default; Pod Security Admission
  allows this sysctl in `v1.29+` versions of the baseline and restricted policies. ([#121240](https://github.com/kubernetes/kubernetes/pull/121240), [@HirazawaUi](https://github.com/HirazawaUi))
- `kubelet` now allows pods to use the `net.ipv4.tcp_keepalive_time` sysctl by default

- Pod SecurityContext sysctls name parameter for update requests where the existing object's sysctl contains slashes and kubelet sysctl whitelist support contains slashes. ([#102393](https://github.com/kubernetes/kubernetes/pull/102393), [@mengjiao-liu](https://github.com/mengjiao-liu)) [SIG Apps, Auth, Node, Storage and Testing]...

  // +optional
  optional int64 fsGroup = 5;

  // Sysctls hold a list of namespaced sysctls used for the pod. Pods with unsupported
  // sysctls (by the container runtime) might fail to launch.
  // Note that this field cannot be set when spec.os.name is windows.
  // +optional
  repeated Sysctl sysctls = 7;

* The Sysctls experimental feature has been promoted to beta (enabled by default via the `Sysctls` feature flag). PodSecurityPolicy and Pod objects now have fields for specifying and controlling sysctls. Alpha sysctl annotations will be ignored by 1.11+ kubelets. All alpha sysctl annotations in existing deployments must be converted to API fields to be effective. ([#6371](https://github.com...

  
  When the feature gate is enabled, kubelet ignores errors that happens during setting the following sysctl values: `vm.overcommit_memory`, `vm.panic_on_oom`, `kernel.panic`, `kernel.panic_on_oops`, `kernel.keys.root_maxkeys`, `kernel.keys.root_maxbytes`. (These sysctl values for the host, not for the containers)
  
  kubelet also ignores an error during opening `/dev/kmsg`.

- Kubelet allows pods to use the `net.ipv4.ip_local_reserved_ports` sysctl by default and the minimal kernel version is 3.16; Pod Security admission allows this sysctl in v1.27+ versions of the baseline and restricted policies. ([#115374](https://github.com/kubernetes/kubernetes/pull/115374), [@pacoxu](https://github.com/pacoxu)) [SIG Auth, Network and Node]

## Urgent Upgrade Notes 

### (No, really, you MUST read this before you upgrade)

- Pod SecurityContext and PodSecurityPolicy supports slash as sysctl separator. ([#106834](https://github.com/kubernetes/kubernetes/pull/106834), [@mengjiao-liu](https://github.com/mengjiao-liu)) [SIG Apps, Architecture, Auth, Node, Security and Testing]

pkg syscall (netbsd-arm64-cgo), func Syscall(uintptr, uintptr, uintptr, uintptr) (uintptr, uintptr, Errno)
pkg syscall (netbsd-arm64-cgo), func Sysctl(string) (string, error)
pkg syscall (netbsd-arm64-cgo), func SysctlUint32(string) (uint32, error)
pkg syscall (netbsd-arm64-cgo), func TimevalToNsec(Timeval) int64

pkg syscall (darwin-arm64), func Syscall9(uintptr, uintptr, uintptr, uintptr, uintptr, uintptr, uintptr, uintptr, uintptr, uintptr) (uintptr, uintptr, Errno)
pkg syscall (darwin-arm64), func Sysctl(string) (string, error)
pkg syscall (darwin-arm64), func SysctlUint32(string) (uint32, error)
pkg syscall (darwin-arm64), func TimevalToNsec(Timeval) int64
pkg syscall (darwin-arm64), func Truncate(string, int64) error