Automatic merge from submit-queue (batch tested with PRs 57867, 58490, 58502, 58134). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Openstack: register metadata.hostname as node name
**What this PR does / why we need it**:
Currently Openstack can boot up instances with the name like `xyz/abc`, which is not a valid kubelet node name. While `hostname` retrieved from `meta_data.json` has already been sanitized
by Openstack to valid DNS-1123 format string. It's safe to register this `metadata.hostname` as valid kubelet node name.
/kind bug
/sig openstack
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes#57765
**Special notes for your reviewer**:
/assign @dims @FengyunPan
**Release note**:
```release-note
Openstack: register metadata.hostname as node name
```
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