Add a log-file-max-size flag to fix large logfile (>1.8GB) truncation.

[yuwenma]

What this PR does / why we need it:
Allows klog users to disable the max-size limitation (cleanup log-file when exceeds 1.8GB) when flag log-file is applied.

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 #55

Special notes for your reviewer:

Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.

Release note:

NONE

[yuwenma]

/assign @dims
/cc @mborsz @tallclair @wojtek-t

[dims]

/assign @DirectXMan12

[dims]

Solly, currently when someone uses log-file, we wrap around the file when it reaches 1.8GB. I don't think we should do that as we basically lose the log of what happened until then unless someone logrotate (with copy truncation) out. By default if someone uses log-file we should honor that and let them use other tools to manage the logfile (like logrotate). If they do want to specify a max size, we can use a new toggle log-file-max-size ... WDYT? please see the referenced issues for the discussion

[yuwenma]

@tallclair Refactored the code to precompute the max number. PTAL

[dims]

@yuwenma can you please look at the lint error in the CI?

[DirectXMan12]

If they do want to specify a max size, we can use a new toggle log-file-max-size ... WDYT? please see the referenced issues for the discussion

When did --log-file go in? That seems reasonable to me, although to avoid breaking people by out-of-disking them, we should default log-file-max-size to 1.8 GiB and then warn if it's not set for a couple of releases, to give people some time to fix their clusters.

[DirectXMan12]

(FWIW, I agree that having no limit is probably the expected behavior, but in case anyone is accidentally depending on this behavior, it's probably good to give them at least a release's worth of heads-up)

[yuwenma]

@DirectXMan12 Updated the default to be 1800MB. 😃

[dims]

/approve

leaving /lgtm for @tallclair or @DirectXMan12

[tallclair]

/lgtm

[k8s-ci-robot]

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