* etcd3: update etcd godep to 3.0.9 to address TestWatch issues ([#32822](https://github.com/kubernetes/kubernetes/pull/32822), [@timothysc](https://github.com/timothysc))
* etcd3: update to etcd 3.0.10 ([#33393](https://github.com/kubernetes/kubernetes/pull/33393), [@timothysc](https://github.com/timothysc))

from writing to etcd during an etcd2 -> etcd3 migration.  HA installations cannot
be migrated at the current time using the official Kubernetes procedure.

1.6 will also default to protobuf encoding if using etcd3.  **This change is
irreversible.**  To rollback, you must restore from a backup made before the
protobuf/etcd3 switch, and any changes since the backup will be lost.  As 1.5

* etcd version 2.2.1
  * etcd version 3.0.14 [has also been validated](https://k8s-gubernator.appspot.com/builds/kubernetes-jenkins/logs/ci-kubernetes-e2e-gce-etcd3/) but does require [specific configuration steps](https://coreos.com/blog/migrating-applications-etcd-v3.html)

## Changelog since v1.5.0-beta.3

### Other notable changes

> cluster1

```sh
export MINIO_ETCD_ENDPOINTS="http://remote-etcd1:2379,http://remote-etcd2:4001"
export MINIO_DOMAIN=domain.com
export MINIO_PUBLIC_IPS=44.35.2.1,44.35.2.2,44.35.2.3,44.35.2.4
minio server http://rack{1...4}.host{1...4}.domain.com/mnt/export{1...32}
```

> cluster2

```sh
export MINIO_ETCD_ENDPOINTS="http://remote-etcd1:2379,http://remote-etcd2:4001"
export MINIO_DOMAIN=domain.com

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"context"
	"errors"
	"fmt"

	etcd "go.etcd.io/etcd/client/v3"
)

var errEtcdUnreachable = errors.New("etcd is unreachable, please check your endpoints")

func etcdErrToErr(err error, etcdEndpoints []string) error {
	if err == nil {
		return nil
	}
	switch err {

  - 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

* Add --etcd-compaction-interval to apiserver for controlling request of compaction to etcd3 from apiserver. ([#51765](https://github.com/kubernetes/kubernetes/pull/51765), [@mitake](https://github.com/mitake))
* Apply algorithm in scheduler by feature gates. ([#52723](https://github.com/kubernetes/kubernetes/pull/52723), [@k82cn](https://github.com/k82cn))

* mark container-port flag as deprecated ([#25072](https://github.com/kubernetes/kubernetes/pull/25072), [@AdoHe](https://github.com/AdoHe))
* Provide flags to use etcd3 backed storage ([#24455](https://github.com/kubernetes/kubernetes/pull/24455), [@hongchaodeng](https://github.com/hongchaodeng))

### Other notable changes

```
rm -rf /tmp/etcd-data.tmp && mkdir -p /tmp/etcd-data.tmp && \
  podman rmi gcr.io/etcd-development/etcd:v3.3.9 || true && \
  podman run \
  -p 2379:2379 \
  -p 2380:2380 \
  --mount type=bind,source=/tmp/etcd-data.tmp,destination=/etcd-data \
  --name etcd-gcr-v3.3.9 \
  gcr.io/etcd-development/etcd:v3.3.9 \
  /usr/local/bin/etcd \
  --name s1 \
  --data-dir /etcd-data \

	jsoniter "github.com/json-iterator/go"
	"github.com/minio/minio-go/v7/pkg/set"
	"github.com/minio/minio/internal/config"
	"github.com/minio/minio/internal/kms"
	"github.com/puzpuzpuz/xsync/v3"
	"go.etcd.io/etcd/api/v3/mvccpb"
	etcd "go.etcd.io/etcd/client/v3"
)

var defaultContextTimeout = 30 * time.Second

func etcdKvsToSet(prefix string, kvs []*mvccpb.KeyValue) set.StringSet {
	users := set.NewStringSet()
	for _, kv := range kvs {