Alibaba Cloud Service Mesh:Enable distributed tracing in ASM

Propagate trace context headers in your application

The Bookinfo sample application demonstrates how to propagate trace context headers in different languages.

def getForwardHeaders(request):
    headers = {}
    # x-b3-*** headers can be populated using the opentracing span
    span = get_current_span()
    carrier = {}
    tracer.inject(
        span_context=span.context,
        format=Format.HTTP_HEADERS,
        carrier=carrier)
    headers.update(carrier)
    # ...

    incoming_headers = ['x-request-id']

    # ...

    for ihdr in incoming_headers:
        val = request.headers.get(ihdr)
        if val is not None:
            headers[ihdr] = val
    return headers

@GET
@Path("/reviews/{productId}")
public Response bookReviewsById(@PathParam("productId") int productId,
                            @HeaderParam("end-user") String user,
                            @HeaderParam("x-request-id") String xreq,
                            @HeaderParam("x-b3-traceid") String xtraceid,
                            @HeaderParam("x-b3-spanid") String xspanid,
                            @HeaderParam("x-b3-parentspanid") String xparentspanid,
                            @HeaderParam("x-b3-sampled") String xsampled,
                            @HeaderParam("x-b3-flags") String xflags,
                            @HeaderParam("x-ot-span-context") String xotspan) {

  if (ratings_enabled) {
    JsonObject ratingsResponse = getRatings(Integer.toString(productId), user, xreq, xtraceid, xspanid, xparentspanid, xsampled, xflags, xotspan);

Access the Bookinfo application

Open the following URL in your browser:

http://{IP address of the ingress gateway}/productpage

Replace {IP address of the ingress gateway} with the actual IP address of your ASM ingress gateway.

View trace data in the OpenTelemetry console

After you deploy your application with header propagation, view the trace data in the Managed Service for OpenTelemetry console.

FAQ

Why can't I see trace data after enabling tracing in the ASM console?

This can happen when the daily usage quota is exceeded. When actual data volume exceeds the configured limit, the system stops data writing and no traces are displayed.

To verify and fix this issue:

1. View the trace push logs.

   1. Obtain the kubeconfig file of the cluster and use kubectl to connect to the cluster. For more information, see Obtain the kubeconfig file of a cluster and use kubectl to connect to the cluster.

   2. Run the following command to view the trace push logs of the pods related to the tracing-on-external-zipkin deployment in the istio-system namespace:

      kubectl logs "$(kubectl get pods -n istio-system -l app=tracing -o jsonpath='{.items[0].metadata.name}')" -n istio-system -c nginx

      The status code 406 is recorded in the trace push logs.

2. View the quota usage.

   1. Log on to the Managed Service for OpenTelemetry console.

   2. In the left-side navigation pane, expand System Configuration, then click Cluster Configuration to view the quota usage.

      

   If the actual usage exceeds the configured limit, the system stops data writing and no trace information is displayed.

3. Increase the quota.

   1. On the Cluster Configuration page, increase the quota value under Quota Configuration, then click Save.

   2. In the Note dialog that appears, click OK.

Why does the trace ID change after passing through the ingress gateway or sidecar?

The sidecar proxy regenerates propagation headers when it receives a request with incomplete trace context. To preserve your trace ID, include the minimum required headers:

• B3 format: x-b3-traceid and x-b3-spanid

• W3C Trace Context format: traceparent