Pass Burst and QPS client params to clusterapi k8s clients

[kdw174]

What type of PR is this?

/kind bug

What this PR does / why we need it:

Passes the kubeClientBurst and kubeClientQPS flags to the clusterapi provider k8s clients to allow tuning of client and avoid excessive client-side throttling.

Which issue(s) this PR fixes:

Fixes #6333

Does this PR introduce a user-facing change?

kubeClientBurst and kubeClientQPS flags are now passed to the clusterapi provider k8s clients

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

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: kdw174 / name: Kyle Weaver (4778d9e, 2754aa4, 1cc6239)

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[elmiko]

thanks for the PR @kdw174 !

i think this looks good, i wonder if we should add something to the clusterapi/README.md to let users know about this?

also, do you think we would ever need to vary these values between the management kubeconfig and the workload kubeconfig?

[elmiko]

my second question is more speculative, i think this PR is probably good as it is for now.

[kdw174]

I don't think we should add that as part of the clusterapi readme since this parameter isn't clusterapi provider specific. The clients are going to have the same default QPS and Burst config they had before.

I could add it to the cluster-autoscaler FAQ here https://github.com/kubernetes/autoscaler/blob/master/cluster-autoscaler/FAQ.md#what-are-the-parameters-to-ca if you think that makes sense

[elmiko]

thanks. i feel like we should definitely have these options in the main FAQ, but it might be better to open that as another PR since it will require approvers from the core team to approve.

i'm ready to approve this, but i just thought of one other question. is it possible that a user could set the QPS and burst in the kubeconfig itself? (i'm not sure this is even possible but i want to make sure we don't overwrite a config value from the kubeconfig if it's already present)

[kdw174]

I don't believe it's possible to set the qps or burst from the kubeconfig as this is the pattern the default client follows in cluster-autoscaler. Digging through the BuildConfigFromFlags function that's called, I wasn't able to find anywhere that the qps could be set from the kubeconfig or an env var.

[elmiko]

ack, thanks for investigating @kdw174

/approve
/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: elmiko, kdw174

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• cluster-autoscaler/cloudprovider/clusterapi/OWNERS [elmiko]

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