feat: Add support for CPU quota configs for node pools

[stanley98yu]

Add support for setting CPU limits on pods and reallocation intervals as cpu_cfs_quota and cpu_cfs_quota_period under kubelet_config for node pools.

Issue reference: #962.

[comment-bot-dev]

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[morgante]

Thanks for the contribution! Do you mind adding this to one of the examples/tests?

[stanley98yu]

@morgante Thank you for reviewing! I added in a test as requested, but I have a question. There's a note on the Terraform Google provider docs that says:

Note: At the time of writing (2020/08/18) the GKE API rejects the none value and accepts an invalid default value instead. While this remains true, not specifying the kubelet_config block should be the equivalent of specifying none.

My understanding is if the user wants cpu_manager_policy to be "none" then they would not specify any kubelet_config field at all (so the kubelet_config block won't be generated), and to default to "static" if kubelet_config is generated to avoid the issue above. Is this correct or at least the best way to handle this?

[stanley98yu]

It's also not clear to me why the build is failing. Seems like #1035 was facing the same issue but approved anyway?

[morgante]

My understanding is if the user wants cpu_manager_policy to be "none" then they would not specify any kubelet_config field at all (so the kubelet_config block won't be generated), and to default to "static" if kubelet_config is generated to avoid the issue above. Is this correct or at least the best way to handle this?

Yes, I think your understanding is correct and the implementation you have (conditionally generating the block) is the right workaround.

It's also not clear to me why the build is failing. Seems like #1035 was facing the same issue but approved anyway?

It's an unrelated issue, we can ignore that test failure.