Instrument Kubernetes API and Allocator with Tracing

[cyriltovena]

Is your feature request related to a problem? Please describe.
It would be great to be able to trace requests and their downstream pair together to troubleshoot issues.

Describe the solution you'd like
Currently we are using an old version of OpenCensus, but if we move to OpenTelemetry we should be able to add tracing to the Kubernetes API rest client and the allocator.

Open Telemetry doesn't seems to be available yet but the recommendations seems to be to use OpenCensus and OpenTracing together for now

I want to start instrumenting production code today. What should I use?
We are still working on the first production-ready release of OpenTelemetry. For those who
want to start instrumenting production code immediately, use either OpenCensus or
OpenTracing. OpenTelemetry will provide compatibility bridges and there is no need to wait
for production-ready OpenTelemetry APIs in your language.

For now we should update GRPC version and OpenCensus version to match then instrument the http allocator service and the Kubernetes REST client using OpenTracing (https://opentracing.io/).

Describe alternatives you've considered
Wait for OpenTelemetry ?

Additional context

• Add allocations metrics #963 Adds more allocator instrumentation with a comment where to integrate tracing.
• Update to opencensus v0.22 #893 This was an attempt to update OpenCensus but was requiring a GRPC update it would be great to move to OpenTelemetry.
• See https://opensource.googleblog.com/2019/05/opentelemetry-merger-of-opencensus-and.html
• https://opentracing.io/
• https://opencensus.io/
• https://opentelemetry.io/

[github-actions]

'This issue is marked as Stale due to inactivity for more than 30 days. To avoid being marked as 'stale' please add 'awaiting-maintainer' label or add a comment. Thank you for your contributions '

[markmandel]

We do need to move to OTel at some point... so if we do that, we should probably do this. How do other people feel?

[github-actions]

'This issue is marked as Stale due to inactivity for more than 30 days. To avoid being marked as 'stale' please add 'awaiting-maintainer' label or add a comment. Thank you for your contributions '