CheckZipkinPortAvailability checks to see if Zipkin Port is available on the machine.

CleanupZipkinTracingSetup cleans up the Zipkin tracing setup on the machine.

SetupZipkinTracing sets up zipkin tracing which involves a) Setting up port-forwarding from localhost to zipkin pod on the cluster (pid of the process doing Port-Forward is stored in a global variable).

ZipkinNamespace namespace where zipkin pod runs.

ZipkinPort port exposed by the Zipkin Pod https://github.com/knative/serving/blob/master/config/monitoring/200-common/100-zipkin.yaml#L25 configures the Zipkin Port on the cluster.

ZipkinTraceEndpoint port-forwarded zipkin endpoint.

ZipkinTraceIDHeader HTTP response header key to be used to store Zipkin Trace ID.