vpa: Follow Kubernetes logging guideline

[ialidzhikov]

Which component are you using?:

vertical-pod-autoscaler

Is your feature request designed to solve a problem? If so describe the problem this feature should solve.:

Currently, the logging in the VPA components does not follow the best practices and guidelines which are followed in the K8s ecosystem. VPA, as a core K8s component, should follow sig-instrumentation's Logging guide.

For example, let's take

autoscaler/vertical-pod-autoscaler/pkg/updater/logic/updater.go

Line 220 in bd8153b

klog.V(2).Infof("evicting pod %v", pod.Name)

. The issues with this log are:

• It does not start with a capital letter. From sig-instrumentation's Logging guide: "Start from a capital letter."
• It is not a structured log. See Structured Logging.

Describe the solution you'd like.:
Follow sig-instrumentation's Logging guide in the VPA's codebase.

Describe any alternative solutions you've considered.:
N/A

Additional context.:
N/A

[Shubham82]

/area vertical-pod-autoscaler

[Shubham82]

cc @voelzmo @kwiesmueller