* AWS kube-up: Increase timeout waiting for docker start ([#25405](https://github.com/kubernetes/kubernetes/pull/25405), [@justinsb](https://github.com/justinsb))
* Sort resources in quota errors to avoid duplicate events ([#25161](https://github.com/kubernetes/kubernetes/pull/25161), [@derekwaynecarr](https://github.com/derekwaynecarr))

					Code:      apiErr.Code,
					Message:   apiErr.Description,
					Key:       object.ObjectName,
					VersionID: object.VersionID,
				}
				continue
			}
		}

		// Avoid duplicate objects, we use map to filter them out.
		if _, ok := objectsToDelete[object]; !ok {
			objectsToDelete[object] = index
		}
	}

	toNames := func(input map[ObjectToDelete]int) (output []ObjectToDelete) {

- Manual change of a failed job condition status to False does not result in duplicate conditions ([#110292](https://github.com/kubernetes/kubernetes/pull/110292), [@mimowo](https://github.com/mimowo)) [SIG Apps]
- OpenAPI will no longer duplicate these schemas:
  - io.k8s.apimachinery.pkg.apis.meta.v1.DeleteOptions_v2
  - io.k8s.apimachinery.pkg.apis.meta.v1.ObjectMeta_v2

* Fixes an issue with RBAC reconciliation that could cause duplicated subjects in some bootstrapped rolebindings on each restart of the API server. ([#53239](https://github.com/kubernetes/kubernetes/pull/53239), [@enj](https://github.com/enj))

 *  Fix: Drop cookies that contain ASCII NULL and other bad characters. Previously such cookies
    would cause OkHttp to crash when they were included in a request.
 *  Fix: Release duplicated multiplexed connections. If we concurrently establish connections to an
    HTTP/2 server, close all but the first connection.
 *  Fix: Fail the HTTP/2 connection if first frame isn't `SETTINGS`.

* Adding vmdk file extension for vmDiskPath in vsphere DeleteVolume ([#40538](https://github.com/kubernetes/kubernetes/pull/40538), [@divyenpatel](https://github.com/divyenpatel))
* AWS: Remove duplicate calls to DescribeInstance during volume operations ([#39842](https://github.com/kubernetes/kubernetes/pull/39842), [@gnufied](https://github.com/gnufied))

		for _, user := range q.Users {
			lookupRes, actualGroups, _ := sys.LDAPConfig.GetValidatedDNWithGroups(user)
			if lookupRes != nil {
				groupSet := set.CreateStringSet(actualGroups...)

				// duplicates can be overwritten, fetched groups should be identical.
				cleanQ.Users[lookupRes.NormDN] = groupSet
			}
			// Search for non-normalized DN as well for backward compatibility.
			if _, ok := cleanQ.Users[user]; !ok {

- Fixed a regression in default configurations, which enabled PodDisruptionConditions by default, 
  that prevented the control plane's pod garbage collector from deleting pods that contained duplicated field keys (env. variables with repeated keys or container ports). ([#121380](https://github.com/kubernetes/kubernetes/pull/121380), [@mimowo](https://github.com/mimowo)) [SIG Apps, Auth, Scheduling and Testing]

- Duplicate owner reference entries in create/update/patch requests now get deduplicated by the API server. The client sending the request now receives a warning header in the API response. Clients should stop sending requests with duplicate owner references. The API server may reject such requests as early as 1.24. ([#96185](https://github.com/kubernetes/kubernetes/pull/96185),...

* Made multi-scheduler graduated to Beta and then v1. ([#38871](https://github.com/kubernetes/kubernetes/pull/38871), [@k82cn](https://github.com/k82cn))
* Fixed forming resolver search line for pods: exclude duplicates, obey libc limitations, logging and eventing appropriately. ([#29666](https://github.com/kubernetes/kubernetes/pull/29666), [@vefimova](https://github.com/vefimova))