add workaround for klog/coredns crash issue

[chrisohaver]

What type of PR is this?

/kind bug

What this PR does / why we need it:

Adding a /tmp volume mount resolves the issue in CoreDNS 1.3.1 where CoreDNS will crash when the Kubernetes API shuts down.

This is the same fix as #82128, which was merged into the 1.14 branch. CoreDNS 1.3.1 is installed by kubeadm/kubeup in K8s 1.14 and 1.15, so the fix should be in 1.15 too.

Fixes #85205

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[chrisohaver]

/cc @rajansandeep

[chrisohaver]

/retest

[rajansandeep]

Extra indent needs to be fixed.

- name: tmp
  mountPath: /tmp

[rajansandeep]

Same here as well, extra indent

- name: tmp
  emptyDir: {}

[chrisohaver]

Thanks - same copy paste error in the other files too.
And there was also a tab that snuck into manifests.go.

[rajansandeep]

/kind bug
/priority important-soon

[rajansandeep]

/lgtm
Thank you @chrisohaver
/assign @neolit123 @MrHohn
cc @kubernetes/patch-release-team

[neolit123]

/approve
for kubeadm

[neolit123]

thanks @chrisohaver
ping @kubernetes/patch-release-team

[MrHohn]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: chrisohaver, MrHohn, neolit123

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Needs approval from an approver in each of these files:

• cluster/addons/dns/OWNERS [MrHohn]
• cmd/kubeadm/OWNERS [neolit123]

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[drpaneas]

Thanks for the PR. This fixes the issue indeed.

[blurpy]

Is there anything blocking merge of this? Really hoping to see this fix in the next patch release.

[dims]

/assign @tpepper

needs sign off from the patch release team

[dougm]

The change lgtm, was it not possible to use the automated cherry pick (cherry_pick_pull.sh) for this one?

[tpepper]

The change lgtm, was it not possible to use the automated cherry pick (cherry_pick_pull.sh) for this one?

See also https://github.com/kubernetes/community/blob/master/contributors/devel/sig-release/cherry-picks.md

It's not necessary to re-do this via the cherrypick automation, but just want to FYI in the event in the future you have a choice between using the automation versus manual.

[dougm]

@tpepper yes, the manual pick looks correct now, agreed no need for re-do. In general though, automated cherry-pick should be preferred when there are no merge conflicts. Helps avoid the manual errors that happened here and git tooling plays better when the original commit hash is maintained.