Fixes reading /root/.docker/config.json on debian

[blakebarnett]

Debian and probably others apparently don't automatically default to using the root account if it's not specified.

ref: kubernetes/kubernetes#45487 (comment)

[k8s-ci-robot]

Hi @blakebarnett. Thanks for your PR.

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[blakebarnett]

/assign @justinsb

[justinsb]

/ok-to-test

Who does the systemd service run as without this @blakebarnett ? I did notice that HOME was not set correctly on systemd - I wonder if that is the problem. But maybe setting this has the effect of setting HOME?

[chrislovecnm]

So running stuff as root always gives me a chill down my spine. Shouldn't we have a privileged kubernetes user that is running kubelet?

[blakebarnett]

It's a good idea, but adds user management across all supported OSes into the mix...

[blakebarnett]

@justinsb I haven't verified but I believe it's nobody on Debian based distros. Setting HOME worked for CoreOS and (I think) RH.

[justinsb]

I checked on CoreOS & Debian and it looks like it runs as root without the env. I like making it explicit therefore (so we know to consider changing the user later), and the "side-effect" of getting the env is great!

/lgtm

/ok-to-test

[k8s-github-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: blakebarnett, justinsb

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[justinsb]

/retest

[justinsb]

Test failure filed as kubernetes/kubernetes#51429

[KashifSaadat]

/retest

[k8s-github-robot]

/test all [submit-queue is verifying that this PR is safe to merge]

[k8s-github-robot]

Automatic merge from submit-queue

[blakebarnett]

Ah that makes more sense. 👍