✨ Use klog as kubebuilder default logger

[astraw99]

Fixes #3036
Fixes kubernetes-sigs/controller-runtime#2024

To make the log output consistent with K8s core components (kube-apiserver, kube-controller-manager, etc), and
more human readable.

Test results:
Before this PR, the kubebuilder generated controller-manager log is:

1.6656692709539523e+09  INFO    controller-runtime.metrics      Metrics server is starting to listen    {"addr": "127.0.0.1:8080"}
1.665669270954326e+09   INFO    setup   starting manager
1.6656692709546785e+09  INFO    Starting server {"path": "/metrics", "kind": "metrics", "addr": "127.0.0.1:8080"}
1.6656692709546802e+09  INFO    Starting server {"kind": "health probe", "addr": "[::]:8081"}

After this PR, the kubebuilder generated controller-manager log is:

I1016 23:41:42.700531   61722 listener.go:44] "controller-runtime/metrics: Metrics server is starting to listen" addr=":8080"
I1016 23:41:42.701073   61722 main.go:115] "setup: starting manager"
I1016 23:41:42.701251   61722 internal.go:362] "Starting server" kind="health probe" addr="[::]:8081"
I1016 23:41:42.701255   61722 internal.go:362] "Starting server" path="/metrics" kind="metrics" addr="[::]:8080"

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @astraw99. Thanks for your PR.

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[camilamacedo86]

Hi @astraw99,

Thank you for your contribution 🥇.

Would not the change done in controller-runtime kubernetes-sigs/controller-runtime#2029 also address your motivation?

(ihmo) we need to discuss if we would like to change the default log lib to klog. For that, we need to understand what are the motivations for the controller-runtime use of zap first. Would possible for you to open an issue with the proposed idea and check out it and add the pros and cons that you see to do this change?

An alternative option would to be add a FAQ section in the docs describing to users how they can customize the scaffold to use klog instead.

[camilamacedo86]

/ok-to-test

[camilamacedo86]

@alvaroaleman @joelanford do you remember why we implement the log zap feature in controller-runtime instead of using klog?

c/c @jmrodri @varshaprasad96

[camilamacedo86]

/hold

Only to avoid it getting merged before it has enough reviews and discussions.

[camilamacedo86]

Cons: It will add a new dep for the projects which increases the cost for maintainability.

[astraw99]

Hi @astraw99,

Thank you for your contribution 🥇.

Would not the change done in controller-runtime kubernetes-sigs/controller-runtime#2029 also address your motivation?

(ihmo) we need to discuss if we would like to change the default log lib to klog. For that, we need to understand what are the motivations for the controller-runtime use of zap first. Would possible for you to open an issue with the proposed idea and check out it and add the pros and cons that you see to do this change?

An alternative option would to be add a FAQ section in the docs describing to users how they can customize the scaffold to use klog instead.

Opened a proposal #3036, including log format comparison and pros/cons.
PTAL thanks.

[astraw99]

After the issue discussion, we prefer to use zap as default logger.
Will close this proposal PR.