migrate to kubelet config file

[rphillips]

Migrates the kubelet to a kubelet.conf file.

The customer typically had to set configuration settings within the kubelet unit file and pass command-line flags to reconfigure the Kubelet. With this patch, the configuration file will allow a subset of options to be set by the customer.

[rphillips]

/cc @derekwaynecarr

[ashcrow]

I did a quick look through and it looks good.

[abhinavdahiya]

why this extra line ?

[rphillips]

fixed in 0ee9e75.

[rphillips]

/test unit

[abhinavdahiya]

/approve

@aaronlevy do you mind taking a quick look

[aaronlevy]

To my naive eyes this lgtm. I'm assuming flags that are left over are not represented in the config file?

Might want someone else from pod team / someone more familiar with kubelet mechanics to take a pass - but could always be follow up.

Not strictly related to this, but could also drop --exit-on-lock-contention flag -- I really really hope no one is still trying to self-host the kubelet (we might want to get that deprecated/removed upstream -- and I'll apologize to everyone for asking for it in the first place...)

[rphillips]

Removed the --exit-on-lock-contention. The rest of the flags have not been migrated into the kubelet configuration upstream yet.

[aaronlevy]

One last question is that it looks like serialize-image-pulls changed from false to true. Just confirming that this is intentional / expected?

[abhinavdahiya]

/approve cancel

One last question is that it looks like serialize-image-pulls changed from false to true. Just confirming that this is intentional / expected?

@aaronlevy good catch.

@rphillips ?

[rphillips]

@aaronlevy good catch.

fixed and squashed.

[aaronlevy]

This has been dragging on (apologies) so I can lgtm, but also just noticed that --lock-file=/var/run/lock/kubelet.lock also still exists - which is also part of the self-hosting kubelet behavior we no longer use.

[rphillips]

@aaronlevy updated to remove the lock

[aaronlevy]

/lgtm

[abhinavdahiya]

/approve

[openshift-ci-robot]

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