Document how to use pprof which was introduced in controller-runtime v0.15.x

[zqzten]

What do you want to happen?

As pprof support been introduced to controller-runtime, we can follow up to make it available (and visible) to end users of kubebuilder. This issue tracks the tasks needed TBD, please comment if I miss or get wrong on anything.

• upgrade controller-runtime to v0.15.x
• add a flag to configure the pprof serving address in main.go of kubebuilder scaffold
• address the security issues (possible sensitive information leak) on exposing pprof in comments or the kubebuilder book

For the third task, I'm not sure what best practice we shall provide to end users so this is RFC.

For now, I can think up two possible ways:

• defaulting the pprof bind address to 127.0.0.1:xxxx
• protect the pprof endpoint by kube-rbac-proxy just like the metrics does (this would require more tasks TBD)

Please comment your preference or other opinions if applicable, thanks!

Extra Labels

/kind documentation

[camilamacedo86]

The comments above were hidden for simplicity. While we've decided to document its usage rather than include it in the default scaffold, you can refer to the hidden comments for more context on this decision. Nevertheless, introducing it as an optional plugin for the scaffold could be a viable alternative. This option would certainly be a beneficial addition.

To address this issue we must:

• Create a doc under the reference to let users know how to use this option
• Optionally we could address it via an Optional Plugin to update the default scaffold within this option. (I would recommend we doc first and then work in the PR with the proposal solution for it as a plugin as follow up)