As this code is still very new, it has not been heavily optimized yet;
  while it is expected to _eventually_ have better performance than the
  iptables backend, very little performance testing has been done so far. ([#121046](https://github.com/kubernetes/kubernetes/pull/121046), [@danwinship](https://github.com/danwinship))

  - `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

// deleted/overwritten version. This version is visible _only_to the scanner routine, for subsequent deletion.
// This kind of tracking is necessary since a version's tiered content is deleted asynchronously.

// Backend directory tree structure:
// disk1/
// └── bucket
//     └── object
//         ├── a192c1d5-9bd5-41fd-9a90-ab10e165398d
//         │   └── part.1
//         ├── c06e0436-f813-447e-ae5e-f2564df9dfd4

#### Audit Logging
* [alpha] Advanced Auditing enhances the Kubernetes API [audit logging](https://kubernetes.io/docs/tasks/debug/debug-cluster/audit/#log-backend) capabilities through a customizable policy, pluggable audit backends, and richer audit data.

#### Encryption at Rest

* fix detach azure disk back off issue which has too big lock in failure retry condition ([#76573](https://github.com/kubernetes/kubernetes/pull/76573), [@andyzhangx](https://github.com/andyzhangx))
* Ensure the backend pools are set correctly for Azure SLB with multiple backend pools (e.g. outbound rules) ([#76691](https://github.com/kubernetes/kubernetes/pull/76691), [@feiskyer](https://github.com/feiskyer))

- Kube-apiserver: redirect responses are no longer returned from backends by default. Set `--aggregator-reject-forwarding-redirect=false` to continue forwarding redirect responses. ([#112193](https://github.com/kubernetes/kubernetes/pull/112193), [@jindijamie](https://github.com/jindijamie)) [SIG API Machinery and Testing]

* kube-up.sh no longer supports "centos" and "local" providers ([#76711](https://github.com/kubernetes/kubernetes/pull/76711), [@dims](https://github.com/dims))
* Ensure the backend pools are set correctly for Azure SLB with multiple backend pools (e.g. outbound rules) ([#76691](https://github.com/kubernetes/kubernetes/pull/76691), [@feiskyer](https://github.com/feiskyer))

fronted by an L7 load balancer that already mitigates these http/2 attacks may choose not to enable the kube-apiserver mitigation to avoid disrupting load balancer → kube-apiserver connections if http/2 requests from multiple clients share the same backend connection. An API server on a private network may choose not to enable the kube-apiserver mitigation to prevent performance regressions for unauthenticated clients. Authenticated requests rely on the fix in golang.org/x/net v0.17.0 alone. https:...

* restored normalization of custom `--etcd-prefix` when `--storage-backend` is set to etcd3 ([#42506](https://github.com/kubernetes/kubernetes/pull/42506), [@liggitt](https://github.com/liggitt))



# v1.5.5

### etcd moves to version 3.5.0