Fixes kubernetes/kubeadm#347: empty node name when joining nodes with kubeadm

[erhudy]

Node name discovery failed on kubeadm join. If a node name
is not explicitly provided, it will be looked up.

What this PR does / why we need it: kubeadm join fails because the preflight checks always see an empty node name. This corrects that issue.

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes kubernetes/kubeadm#347

Special notes for your reviewer:

Release note:

kubeadm: Fix join preflight check false negative

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[k8s-ci-robot]

Hi @erhudy. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[erhudy]

/assign @luxas

[luxas]

/ok-to-test
/lgtm

Thanks @erhudy!

/assign @timothysc

[k8s-github-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: erhudy, luxas

Associated issue: 347

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these OWNERS Files:

• cmd/kubeadm/OWNERS [luxas]

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[luxas]

This PR replaces #49073

[erhudy]

/test pull-kubernetes-verify

[erhudy]

/retest

[luxas]

/retest

[luxas]

/retest

[fejta-bot]

/retest
This bot automatically retries jobs that failed/flaked on approved PRs (send feedback to @fejta).

Review the full test history for this PR.

[erhudy]

/test pull-kubernetes-e2e-gce-etcd3

[erhudy]

/retest

[luxas]

/retest

[luxas]

/retest

[luxas]

/retest

[k8s-github-robot]

Automatic merge from submit-queue

[k8s-cherrypick-bot]

Commit found in the "release-1.7" branch appears to be this PR. Removing the "cherrypick-candidate" label. If this is an error find help to get your PR picked.