Use etcdutl instead of etcdctl for restoring an etcd cluster

[adityasamant25]

This is a Bug Report

Problem:
This issue refers to the page
Kubernetes Documentation > Tasks > Administer a Cluster > Operating etcd clusters for Kubernetes
https://kubernetes.io/docs/tasks/administer-cluster/configure-upgrade-etcd/

In the section titled "Restoring an etcd cluster", the commands use the etcdctl utility to restore from an existing snapshot.
Using etcdctl for restoring snapshots is deprecated since etcd version 3.5.x
Usage of this command displays a deprecation warning and suggests to use etcdutl utility instead as shown below.

ubuntu@kubemaster:~$ etcdctl version
etcdctl version: 3.5.10
API version: 3.5
ubuntu@kubemaster:~$ ETCDCTL_API=3 etcdctl --endpoints 10.2.0.9:2379 snapshot restore snapshot.db
Deprecated: Use `etcdutl snapshot restore` instead.

I feel this change is necessary as the etcd official documentation has already changed to reflect the use of the etcdutl utility, as can be seen in the etcd documentation referenced in this section - https://etcd.io/docs/v3.6/op-guide/recovery/#restoring-a-cluster.

Proposed Solution:
I have raised a PR to depict the use of the etcdutl utility for restoring from an existing snapshot.
#44050

Before submitting the PR, I have tested the changes on a local Kubernetes cluster for v1.28.0 and I can confirm everything works as expected.

Page to Update:
https://kubernetes.io/docs/tasks/administer-cluster/configure-upgrade-etcd/

Kubernetes Version: 1.28.x and above

[adityasamant25]

/assign

[adityasamant25]

I have raised a PR to depict the use of the etcdutl utility for restoring from an existing snapshot.
#44050

Any comments or improvements are welcome.

[dipesh-rawat]

/retitle Use etcdutl instead of etcdctl for restoring an etcd cluster
/language en

[dipesh-rawat]

/sig etcd

[divya-mohan0209]

/triage accepted

[sftim]

Also see #46757