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82 lines
3.9 KiB
82 lines
3.9 KiB
7 years ago
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.. _install_sandboxes_jaeger_tracing:
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Jaeger Tracing
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==============
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The Jaeger tracing sandbox demonstrates Envoy's :ref:`request tracing <arch_overview_tracing>`
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capabilities using `Jaeger <https://uber.github.io/jaeger/>`_ as the tracing provider. This sandbox
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is very similar to the front proxy architecture described above, with one difference:
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service1 makes an API call to service2 before returning a response.
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The three containers will be deployed inside a virtual network called ``envoymesh``.
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All incoming requests are routed via the front envoy, which is acting as a reverse proxy
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sitting on the edge of the ``envoymesh`` network. Port ``80`` is mapped to port ``8000``
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by docker compose (see :repo:`/examples/jaeger-tracing/docker-compose.yml`). Notice that
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all envoys are configured to collect request traces (e.g., http_connection_manager/config/tracing setup in
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:repo:`/examples/jaeger-tracing/front-envoy-jaeger.json`) and setup to propagate the spans generated
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by the Jaeger tracer to a Jaeger cluster (trace driver setup
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in :repo:`/examples/jaeger-tracing/front-envoy-jaeger.json`).
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Before routing a request to the appropriate service envoy or the application, Envoy will take
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care of generating the appropriate spans for tracing (parent/child context spans).
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At a high-level, each span records the latency of upstream API calls as well as information
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needed to correlate the span with other related spans (e.g., the trace ID).
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One of the most important benefits of tracing from Envoy is that it will take care of
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propagating the traces to the Jaeger service cluster. However, in order to fully take advantage
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of tracing, the application has to propagate trace headers that Envoy generates, while making
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calls to other services. In the sandbox we have provided, the simple flask app
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(see trace function in :repo:`/examples/front-proxy/service.py`) acting as service1 propagates
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the trace headers while making an outbound call to service2.
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Running the Sandbox
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~~~~~~~~~~~~~~~~~~~
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The following documentation runs through the setup of an envoy cluster organized
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as is described in the image above.
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**Step 1: Build the sandbox**
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To build this sandbox example, and start the example apps run the following commands::
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$ pwd
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envoy/examples/jaeger-tracing
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$ docker-compose up --build -d
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$ docker-compose ps
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Name Command State Ports
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-------------------------------------------------------------------------------------------------------------
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jaegertracing_service1_1 /bin/sh -c /usr/local/bin/ ... Up 80/tcp
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jaegertracing_service2_1 /bin/sh -c /usr/local/bin/ ... Up 80/tcp
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jaegertracing_front-envoy_1 /bin/sh -c /usr/local/bin/ ... Up 0.0.0.0:8000->80/tcp, 0.0.0.0:8001->8001/tcp
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**Step 2: Generate some load**
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You can now send a request to service1 via the front-envoy as follows::
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$ curl -v $(docker-machine ip default):8000/trace/1
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* Trying 192.168.99.100...
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* Connected to 192.168.99.100 (192.168.99.100) port 8000 (#0)
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> GET /trace/1 HTTP/1.1
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> Host: 192.168.99.100:8000
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> User-Agent: curl/7.43.0
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> Accept: */*
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>
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< HTTP/1.1 200 OK
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< content-type: text/html; charset=utf-8
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< content-length: 89
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< x-envoy-upstream-service-time: 1
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< server: envoy
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< date: Fri, 26 Aug 2016 19:39:19 GMT
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< x-envoy-protocol-version: HTTP/1.1
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<
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Hello from behind Envoy (service 1)! hostname: f26027f1ce28 resolvedhostname: 172.19.0.6
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* Connection #0 to host 192.168.99.100 left intact
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**Step 3: View the traces in Jaeger UI**
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Point your browser to http://localhost:16686 . You should see the Jaeger dashboard.
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Set the service to "front-proxy" and hit 'Find Traces'. You should see traces from the front-proxy.
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Click on a trace to explore the path taken by the request from front-proxy to service1
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to service2, as well as the latency incurred at each hop.
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