Thanks Juca for starting this discussion on the dev list. The topic of making the tracing pluggable came up both in the related issue https://github.com/apache/incubator-openwhisk/issues/2192#issuecomment-300679362 and also in the pull request.
I continue to think a plugable solution is the preferred solution so that others don't also build more one offs that will not suite everyone's purpose. I though opentracing had already come up but maybe that was just a off-list/Slack discussion with Markus Thoemmes. -r
