* Demoted controlplane passthrough flags apiserver-extra-args, controller-manager-extra-args, scheduler-extra-args to alpha flags ([#59882](https://github.com/kubernetes/kubernetes/pull/59882), [@kris-nova](https://github.com/kris-nova))

## 1.9 Release Notes

## WARNING: etcd backup strongly recommended

Before updating to 1.9, you are strongly recommended to back up your etcd data. Consult the installation procedure you are using (kargo, kops, kube-up, kube-aws, kubeadm etc) for specific advice.

- Volume snapshot e2e test to validate PVC and VolumeSnapshotContent finalizer ([#95863](https://github.com/kubernetes/kubernetes/pull/95863), [@RaunakShah](https://github.com/RaunakShah)) [SIG Cloud Provider, Storage and Testing]
- Warns user when executing kubectl apply/diff to a resource currently being deleted. ([#95544](https://github.com/kubernetes/kubernetes/pull/95544), [@SaiHarshaK](https://github.com/SaiHarshaK)) [SIG CLI]

  even if your cluster and node configuration could otherwise allow this. ([#125277](https://github.com/kubernetes/kubernetes/pull/125277), [@iholder101](https://github.com/iholder101)) [SIG Node and Testing]
- Client-go/reflector: warns when the bookmark event for initial events hasn't been received ([#124614](https://github.com/kubernetes/kubernetes/pull/124614), [@p0lyn0mial](https://github.com/p0lyn0mial)) [SIG API Machinery]

  // of whether the variable exists or not. Cannot be updated.
  // More info: https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/#running-a-command-in-a-shell
  // +optional
  repeated string args = 4;

  // Container's working directory.
  // If not specified, the container runtime's default will be used, which
  // might be configured in the container image.
  // Cannot be updated.
  // +optional

- Take the context as the first argument of Schedule. ([#82119](https://github.com/kubernetes/kubernetes/pull/82119), [@wgliang](https://github.com/wgliang))
- Fixed an issue that the correct PluginConfig.Args is not passed to the corresponding PluginFactory in kube-scheduler when multiple PluginConfig items are defined. ([#82483](https://github.com/kubernetes/kubernetes/pull/82483), [@everpeace](https://github.com/everpeace))

- E2e framework: retrying after intermittent `apiserver` failures was fixed in `WaitForPodsResponding` ([#120559](https://github.com/kubernetes/kubernetes/pull/120559), [@pohly](https://github.com/pohly))

- Add a helper function to decode scheduler plugin args. ([#80696](https://github.com/kubernetes/kubernetes/pull/80696), [@hex108](https://github.com/hex108))
- Fix filter plugins are not been called during preemption ([#81876](https://github.com/kubernetes/kubernetes/pull/81876), [@wgliang](https://github.com/wgliang))

- Added warnings to the Services API. Kubernetes now warns for Services in the case of:
  - IPv4 addresses with leading zeros
  - IPv6 address in non-canonical format (RFC 5952) ([#114505](https://github.com/kubernetes/kubernetes/pull/114505), [@aojea](https://github.com/aojea))

## WARNING: etcd backup strongly recommended

Before updating to 1.6, you are strongly recommended to back up your etcd data.
Please consult the installation procedure you are using (kargo, kops, kube-up,
kube-aws, kubeadm etc) for specific advice.

1.6 encourages etcd3, and switching from etcd2 to etcd3 involves a full
migration of data between different storage engines.  You must stop the API