openzipkin/zipkin

Hi, i'm having trouble in implementing the tracing service in ambassador-gateway with zipkin driver. I had configured the tracing service for ambassador as shown below

 apiVersion: getambassador.io/v1
kind: TracingService
metadata:
  name: tracing
spec:
  config:
    collector_endpoint: /api/v2/spans
  driver: zipkin
  service: jaeger-collector.jaeger:9411

I'm able to the see the traces in jaeger UI ,when i made some requests to the services under that gate way. This time i tried instrumenting the code in one of the services by setting the global tracer with following config:

    func initZipkinTracer(service string) {
    collectorService := os.Getenv("COLLECTOR_SERVICE")
    collectorEndPoint := os.Getenv("COLLECTOR_ENDPOINT")
    CollectorURL := "http://" + collectorService + "/" + collectorEndPoint
    loglib.Info("Traces collector URL", "jaeger-collector", CollectorURL)
    reporter := reporterhttp.NewReporter(CollectorURL)
    sampler, err := zipkin.NewCountingSampler(1)
    if err != nil {
        loglib.Fatal("Unable to initiate the zipkin tracer", "error", err)
    }
    localEndpoint := &model.Endpoint{ServiceName: service, Port: uint16(viper.GetInt32("grpc-port"))}
    t, err := zipkin.NewTracer(
        reporter,
        zipkin.WithSampler(sampler),
        zipkin.WithLocalEndpoint(localEndpoint),
    )
    if err != nil {
        loglib.Fatal("Unable to initiate the zipkin tracer", "error", err)
    }
    tracer := zipkinot.Wrap(t)
    opentracing.SetGlobalTracer(tracer)
}

while creating the server i enabled the tracing in the grpc middleware  using otgrpc module as follows:

server.UnaryServerInterceptors(
            otgrpc.OpenTracingServerInterceptor(opentracing.GlobalTracer(), otgrpc.LogPayloads()),
        )

When i made the requests to services which were under ambassador , i'm getting two separate traces one from the ambassador-gateway and the other from the service where we instrumented the code as specified above .Seems like the service is unable to get the info about ambassador tracer from the request context. The expectation is that i need get only one trace which got initiated at ambassador-api-gateway, and the tracing data generated in the service as child span . What are the changes i need to made to fix this issue?