### SIG-cluster-lifecycle

In 1.12, SIG Cluster lifecycle has focused on improving the user experience in kubeadm, by fixing a number of bugs and adding some new important features.

Here is a list of some of the changes that have been made to kubeadm:

- Kubeadm internal config has been promoted to `v1alpha3`:
  - `v1alpha1` has been removed.

* Fix a typo in prometheus-to-sd configuration, that drops some stackdriver metrics. ([#56473](https://github.com/kubernetes/kubernetes/pull/56473), [@loburm](https://github.com/loburm))

- In some cases, a Flex volume resize may leave a PVC with erroneous Resizing condition even after volume has been successfully expanded. Users may choose to delete the condition, but it is not required. ([#71470](https://github.com/kubernetes/kubernetes/issues/71470))

  - [Changelog since v1.20.5](#changelog-since-v1205)
  - [Important Security Information](#important-security-information-1)
    - [CVE-2021-25735: Validating Admission Webhook does not observe some previous fields](#cve-2021-25735-validating-admission-webhook-does-not-observe-some-previous-fields)
  - [Changes by Kind](#changes-by-kind-9)
    - [API Change](#api-change-2)
    - [Feature](#feature-5)
    - [Bug or Regression](#bug-or-regression-9)

- Sometimes, the scheduler incorrectly placed a pod in the "unschedulable" queue instead of the "backoff" queue. This happened when some plugin previously declared the pod as "unschedulable" and then in a later attempt encounters some other error. Scheduling of that pod then got delayed by up to five minutes, after which periodic flushing moved the pod back into the "active" queue. ([#120334](https://github.com/kubernetes/kubernetes/pull/120334),...

  - [Changelog since v1.18.17](#changelog-since-v11817)
  - [Important Security Information](#important-security-information)
    - [CVE-2021-25735: Validating Admission Webhook does not observe some previous fields](#cve-2021-25735-validating-admission-webhook-does-not-observe-some-previous-fields)
  - [Changes by Kind](#changes-by-kind-2)
    - [API Change](#api-change-1)
    - [Feature](#feature)
    - [Bug or Regression](#bug-or-regression-2)

- Using `--log-file` is known to be problematic in 1.15. This presents as things being logged multiple times to the same file. The behaviour and details of this issue, as well as some preliminary attempts at fixing it are documented [here](https://github.com/kubernetes/kubernetes/issues/78734#issuecomment-501372131)

## Urgent Upgrade Notes

### (No, really, you MUST read this before you upgrade)

* Azure cloudprovider: Reduce the polling delay for all azure clients to 5 seconds. This should speed up some operations at the cost of some additional quota. ([#43699](https://github.com/kubernetes/kubernetes/pull/43699), [@colemickens](https://github.com/colemickens))

this validation. Bypassing this validation could allow authenticated requests destined for Nodes to be redirected to the API Server through its private network.

The merged fix enforces validation against the proxying address for a Node. In some cases, the fix can break clients that depend on the `nodes/proxy` subresource, specifically if a kubelet advertises a localhost or link-local address to the Kubernetes control plane. Configuring an egress proxy for egress to the cluster network can...

A new [v1beta3 configuration API](https://github.com/kubernetes/kubeadm/issues/1796). It [iterates over v1beta2](https://pkg.go.dev/k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta3) by adding some long requested features and deprecating some existing ones. The `V1beta3` is now the preferred API version; the `v1beta2` API also remains available and is not yet deprecated.

### etcd moves to version 3.5.0