## Changelog since v1.15.3

### Other notable changes

* Restores compatibility with kubectl client-side validation when structural schemas are present in a CRD which sets spec.preserveUnknownFields=true ([#82666](https://github.com/kubernetes/kubernetes/pull/82666), [@liggitt](https://github.com/liggitt))

func getClusterWriteQuorumMD() MetricDescription {
	return MetricDescription{
		Namespace: clusterMetricNamespace,
		Subsystem: "write",
		Name:      "quorum",
		Help:      "Maximum write quorum across all pools and sets",
		Type:      gaugeMetric,
	}
}

func getClusterHealthStatusMD() MetricDescription {
	return MetricDescription{
		Namespace: clusterMetricNamespace,
		Subsystem: "health",

### Other (Cleanup or Flake)

- Kube-apiserver: sets an upper-bound on the lifetime of idle keep-alive connections and time to read the headers of incoming requests ([#103958](https://github.com/kubernetes/kubernetes/pull/103958), [@liggitt](https://github.com/liggitt)) [SIG API Machinery and Node]

          <type>String</type>
          <required>true</required>
          <description>The unique id for this report set, to be used during POM inheritance and profile injection
            for merging of report sets.
          </description>
          <defaultValue>default</defaultValue>
        </field>
        <field>
          <name>reports</name>
          <version>4.0.0+</version>

      newEntry.setValueReference(valueReference.copyFor(this.valueReferenceQueue, value, newEntry));
      return newEntry;
    }

    /** Sets a new value of an entry. Adds newly created entries at the end of the access queue. */
    @GuardedBy("this")
    void setValue(ReferenceEntry<K, V> entry, K key, V value, long now) {

### Other (Cleanup or Flake)

- Kube-apiserver: sets an upper-bound on the lifetime of idle keep-alive connections and time to read the headers of incoming requests ([#103958](https://github.com/kubernetes/kubernetes/pull/103958), [@liggitt](https://github.com/liggitt)) [SIG API Machinery and Node]

- Changed how the API server handles updates to `.spec.defaultBackend` of Ingress objects.

- Added `--concurrent-daemonset-syncs` command line flag to kube-controller-manager. This value sets the number of workers for the daemonset controller. ([#128444](https://github.com/kubernetes/kubernetes/pull/128444), [@tosi3k](https://github.com/tosi3k))

* 📝 Fix example code with sets in Tutorial - Body - Nested Models 3. PR [#2054](https://github.com/tiangolo/fastapi/pull/2054) by [@hitrust](https://github.com/hitrust).
* 📝 Fix example code with sets in Tutorial - Body - Nested Models 2. PR [#2053](https://github.com/tiangolo/fastapi/pull/2053) by [@hitrust](https://github.com/hitrust).

- kubeadm now properly recognizes Docker 18.09.0 and newer, but still treats 18.06 as the default supported version.
- kubeadm now automatically sets the `--pod-infra-container-image` flag when starting the kubelet.

### SIG IBM Cloud