- The deprecated `--etcd-quorum-read` flag has been removed. Quorum reads are now always enabled when fetching data from etcd. Remove the `--etcd-quorum-read` flag from kube-apiserver invocations before upgrading.
- kube-controller-manager
  - The deprecated `--insecure-experimental-approve-all-kubelet-csrs-for-group` flag has been removed.
- kubelet

  - The deprecated --storage-versions flag has been removed. The storage versions will always be the default value built-in the kube-apiserver binary. ([#67678](https://github.com/kubernetes/kubernetes/pull/67678), [@caesarxuchao](https://github.com/caesarxuchao))

#### Network

- The deprecated flag `--conntrack-max` has been removed from kube-proxy. Users of this flag should switch to `--conntrack-min` and `--conntrack-max-per-core` instead. ([#78399](https://github.com/kubernetes/kubernetes/pull/78399), [@rikatz](https://github.com/rikatz))

  - the `--cloud-provider-gce-lb-src-cidrs` flag has been deprecated. This flag will be removed once the GCE Cloud Provider is removed from kube-apiserver. ([#81094](https://github.com/kubernetes/kubernetes/pull/81094), [@andrewsykim](https://github.com/andrewsykim))

     `--horizontal-pod-autoscaler-use-rest-clients` flag to `true`.

   - In version 1.9, this behavior will be enabled by default, and must be explicitly
     disabled by setting the `--horizontal-pod-autoscaler-use-rest-clients` flag to `false`.

### Cluster Lifecycle

- The `auto-detect` behavior of the kubelet's `--cloud-provider` flag is deprecated.

### **Node**

*   The kubelet `--network-plugin-dir` flag is removed. This flag was deprecated in version 1.7, and is replaced with `--cni-bin-dir`. ([#53564](https://github.com/kubernetes/kubernetes/pull/53564),[ @supereagle](https://github.com/supereagle))

- The new flag `--chunk-size=SIZE` for `kubectl drain` has been promoted to beta, and enabled by default. This flag  may be used to alter the number of items or disable this feature when `0` is passed. ([#100148](https://github.com/kubernetes/kubernetes/pull/100148), [@KnVerey](https://github.com/KnVerey))

* The deprecated `--service-account-private-key-file` flag has been removed from the cloud-controller-manager. The flag is still present and supported in the kube-controller-manager. ([#65182](https://github.com/kubernetes/kubernetes/pull/65182), [@liggitt](https://github.com/liggitt))

* kubectl port-forward no longer supports the deprecated -p <pod-name> flag; the flag itself is unnecessary and should be replaced by just the `<pod-name>`. ([#59705](https://github.com/kubernetes/kubernetes/pull/59705), [@phsiao](https://github.com/phsiao))

 - Kubelet flag `--keep-terminated-pod-volumes` was removed.  This flag was deprecated in 2017. ([#122082](https://github.com/kubernetes/kubernetes/pull/122082), [@carlory](https://github.com/carlory)) [SIG Apps, Node, Storage and Testing]