- Containers which specify a `startupProbe` but not a `readinessProbe` were previously considered "ready" before the `startupProbe` completed, but are now considered "not-ready". ([#92196](https://github.com/kubernetes/kubernetes/pull/92196), [@thockin](https://github.com/thockin)) [SIG Node]

* Fixes an issue where Portworx volumes cannot be mounted if 9001 port is already in use on the host and users remap 9001 to another port. ([#70392](https://github.com/kubernetes/kubernetes/pull/70392), [@harsh-px](https://github.com/harsh-px))

    * To avoid that negative effect only use per pod metrics from pods that are:
    * - ready (so metrics about them should be valid), or
    * - unready but creation and last readiness change timestamps are apart more than 10s (pods that have formerly been ready and so metrics are in at least some cases (pod becoming unready because of overload) very useful).

- Stopped logging error events when waiting for expansion on the kubelet. ([#131408](https://github.com/kubernetes/kubernetes/pull/131408), [@gnufied](https://github.com/gnufied))

- Kubeadm: when adding new control plane nodes with "kubeadm join", ensure that the etcd member addition is performed only if a given member URL does not already exist in the list of members. Similarly, on "kubeadm reset" only remove an etcd member if its ID exists. ([#127621](https://github.com/kubernetes/kubernetes/pull/127621), [@SataQiu](https://github.com/SataQiu)) [SIG Cluster Lifecycle]

CVE-2023-39325 for the API server when the client is unauthenticated. The mitigation may be enabled by setting the `UnauthenticatedHTTP2DOSMitigation` feature gate to `true` (it is disabled by default). An API server 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...

    kubelet does not start pods that require networking before
    [networking is ready](https://github.com/kubernetes/kubernetes/issues/43014).
    This change may require changes to clients that gate pod creation and/or
    scheduling on the node condition `type` `Ready` `status` being `True` for pods
    that need to run prior to the network being ready.
* **Enhance Kubelet QoS**:

- Make sure auto-mounted subpath mount source is already mounted ([#112499](https://github.com/kubernetes/kubernetes/pull/112499), [@andyzhangx](https://github.com/andyzhangx))...

## Changelog since v1.17.13

## Changes by Kind

### Bug or Regression

- An issues preventing volume expand controller to annotate the PVC with `volume.kubernetes.io/storage-resizer` when the PVC StorageClass is already updated to the out-of-tree provisioner is now fixed. ([#94489](https://github.com/kubernetes/kubernetes/pull/94489), [@ialidzhikov](https://github.com/ialidzhikov)) [SIG API Machinery, Apps and Storage]

    * Also updates dependencies of users of debian-base.
    * debian-base version 0.3.1 is already available.
* Fix an issue that pods using hostNetwork keep increasing. ([#67456](https://github.com/kubernetes/kubernetes/pull/67456), [@Huang-Wei](https://github.com/Huang-Wei))