### Network

* Fixed kube-proxy to work correctly with iptables 1.6.2 and later. ([#60978](https://github.com/kubernetes/kubernetes/pull/60978), [@danwinship](https://github.com/danwinship))

* Makes the kube-dns addon optional so that users can deploy their own DNS solution. ([#57113](https://github.com/kubernetes/kubernetes/pull/57113), [@wwwtyro](https://github.com/wwwtyro))

		if s3Err != ErrNone {
			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Err), r.URL)
			return
		}
	case authTypeStreamingUnsignedTrailer:
		// Initialize stream chunked reader with optional trailers.
		rd, s3Err = newUnsignedV4ChunkedReader(r, true, r.Header.Get(xhttp.Authorization) != "")
		if s3Err != ErrNone {
			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Err), r.URL)
			return
		}

### Cloud Provider

- The GCE-only flag `cloud-provider-gce-lb-src-cidrs` is now optional for external cloud providers. ([#76627](https://github.com/kubernetes/kubernetes/pull/76627), [@timoreimann](https://github.com/timoreimann))

    /** The key of the message: Upload File */
    public static final String LABELS_design_file = "{labels.design_file}";

    /** The key of the message: File Name (optional) */
    public static final String LABELS_design_file_name = "{labels.design_file_name}";

    /** The key of the message: Upload */

- Use omitempty for optional Job Pod Failure Policy fields ([#126046](https://github.com/kubernetes/kubernetes/pull/126046), [@mimowo](https://github.com/mimowo)) [SIG Apps]

### Bug or Regression

* Mark the LBaaS v1 of OpenStack cloud provider deprecated. ([#52821](https://github.com/kubernetes/kubernetes/pull/52821), [@FengyunPan](https://github.com/FengyunPan))
* Mark image as deliberately optional in v1 Container struct.  Many objects in the Kubernetes API inherit the container struct and only Pods require the field to be set. ([#48406](https://github.com/kubernetes/kubernetes/pull/48406), [@gyliu513](https://github.com/gyliu513))

* OpenStack cloud provider supports Cinder v3 API. ([#52910](https://github.com/kubernetes/kubernetes/pull/52910), [@FengyunPan](https://github.com/FengyunPan))
* kube-up: Add optional addon CoreDNS.  ([#55728](https://github.com/kubernetes/kubernetes/pull/55728), [@rajansandeep](https://github.com/rajansandeep))
    * Install CoreDNS instead of kube-dns by setting CLUSTER_DNS_CORE_DNS value to 'true'.

- Use omitempty for optional Job Pod Failure Policy fields ([#126046](https://github.com/kubernetes/kubernetes/pull/126046), [@mimowo](https://github.com/mimowo)) [SIG Apps]

### Bug or Regression

* Skip multi-zone e2e tests unless provider is GCE, GKE or AWS ([#27871](https://github.com/kubernetes/kubernetes/pull/27871), [@lukaszo](https://github.com/lukaszo))
* Making DHCP_OPTION_SET_ID creation optional ([#27278](https://github.com/kubernetes/kubernetes/pull/27278), [@activars](https://github.com/activars))

## Changelog since v1.25.13

## Changes by Kind

### API Change

- Mark Job onPodConditions as optional in pod failure policy ([#120211](https://github.com/kubernetes/kubernetes/pull/120211), [@mimowo](https://github.com/mimowo)) [SIG API Machinery and Apps]

### Feature