SkyWalking tracing

The SkyWalking tracing sandbox demonstrates Envoy’s request tracing capabilities using SkyWalking as the tracing provider. This sandbox is very similar to the Zipkin sandbox. All containers will be deployed inside a virtual network called envoymesh.

All incoming requests are routed via the front Envoy, which is acting as a reverse proxy sitting on the edge of the envoymesh network. Port 8000 is exposed by docker compose (see docker-compose.yaml).

Notice that all Envoys are configured to collect request traces (e.g., http_connection_manager/config/tracing setup in front-envoy-skywalking.yaml) and setup to propagate the spans generated by the SkyWalking tracer to a SkyWalking cluster (trace driver setup in front-envoy-skywalking.yaml).

When service1 accepts the request forwarded from front envoy, it will make an API call to service2 before returning a response.

Step 1: Build the sandbox

Change to the examples/skywalking-tracing directory.

To build this sandbox example, and start the example apps run the following commands:

$ pwd
envoy/examples/skywalking-tracing
$ docker-compose pull
$ docker-compose up --build -d
$ docker-compose ps

            Name                              Command                State                                  Ports
--------------------------------------------------------------------------------------------------------------------------------------------------
skywalking-tracing_elasticsearch_1    /tini -- /usr/local/bin/do ... Up (healthy)   0.0.0.0:9200->9200/tcp, 9300/tcp
skywalking-tracing_front-envoy_1      /docker-entrypoint.sh /bin ... Up             10000/tcp, 0.0.0.0:8000->8000/tcp, 0.0.0.0:8001->8001/tcp
skywalking-tracing_service1_1         /bin/sh /usr/local/bin/sta ... Up             10000/tcp
skywalking-tracing_service2_1         /bin/sh /usr/local/bin/sta ... Up             10000/tcp
skywalking-tracing_skywalking-oap_1   bash docker-entrypoint.sh      Up (healthy)   0.0.0.0:11800->11800/tcp, 1234/tcp, 0.0.0.0:12800->12800/tcp
skywalking-tracing_skywalking-ui_1    bash docker-entrypoint.sh      Up             0.0.0.0:8080->8080/tcp

Step 2: Generate some load

You can now send a request to service1 via the front-envoy as follows:

$ curl -v localhost:8000/trace/1
*   Trying ::1...
* TCP_NODELAY set
* Connected to localhost (::1) port 8000 (#0)
> GET /trace/1 HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/7.58.0
> Accept: */*
>
< HTTP/1.1 200 OK
< content-type: text/html; charset=utf-8
< content-length: 89
< server: envoy
< date: Sat, 10 Oct 2020 01:56:08 GMT
< x-envoy-upstream-service-time: 27
<
Hello from behind Envoy (service 1)! hostname: 1a2ba43d6d84 resolvedhostname: 172.19.0.6
* Connection #0 to host localhost left intact

You can get SkyWalking stats of front-envoy after some requests as follows:

$ curl -s localhost:8001/stats | grep tracing.skywalking
tracing.skywalking.cache_flushed: 0
tracing.skywalking.segments_dropped: 0
tracing.skywalking.segments_flushed: 0
tracing.skywalking.segments_sent: 13

Step 3: View the traces in SkyWalking UI

Point your browser to http://localhost:8080 . You should see the SkyWalking dashboard. Set the service to “front-envoy” and set the start time to a few minutes before the start of the test and hit enter. You should see traces from the front-proxy. Click on a trace to explore the path taken by the request from front-proxy to service1 to service2, as well as the latency incurred at each hop.