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Tracing Support

Overview
Tracing-config

Overview

Envoy has rich support for distributed tracing，and supports exporting data to third-party providers (Zipkin, Jaeger, Datadog, etc.)

OpenTelemetry is a CNCF project which is working to become a standard in the space. It was formed as a merger of the OpenTracing and OpenCensus projects.

Contour supports configuring envoy to export data to OpenTelemetry, and allows users to customize some configurations.

Custom service name, the default is contour.
Custom sampling rate, the default is 100.
Custom client sampling rate, the default is 100.
Custom random sampling rate, the default is 100.
Custom the maximum length of the request path, the default is 256.
Customize span tags from literal or request headers.
Customize whether to include the pod’s hostname and namespace.

Tracing-config

In order to use this feature, you must first select and deploy an opentelemetry-collector to receive the tracing data exported by envoy.

First we should deploy an opentelemetry-collector to receive the tracing data exported by envoy

# install operator
kubectl apply -f https://github.com/open-telemetry/opentelemetry-operator/releases/latest/download/opentelemetry-operator.yaml

Install an otel collector instance, with verbose logging exporter enabled:

kubectl apply -f - <<EOF
apiVersion: opentelemetry.io/v1alpha1
kind: OpenTelemetryCollector
metadata:
  name: simplest
  namespace: projectcontour
spec:
  config: |
    receivers:
      otlp:
        protocols:
          grpc:
          http:
    exporters:
      logging:
        verbosity: detailed

    service:
      pipelines:
        traces:
          receivers: [otlp]
          exporters: [logging]
EOF

Define extension service:

kubectl apply -f - <<EOF
apiVersion: projectcontour.io/v1alpha1
kind: ExtensionService
metadata:
  name: otel-collector
  namespace: projectcontour
spec:
  protocol: h2c
  services:
    - name: simplest-collector
      port: 4317
EOF

Update Contour config (needs a Contour deployment restart afterwards):

kubectl apply -f - <<EOF
apiVersion: v1
kind: ConfigMap
metadata:
  name: contour
  namespace: projectcontour
data:
   contour.yaml: |
    tracing:
      # Whether to send the namespace and instance where envoy is located to open, the default is true.
      includePodDetail: true
      # The extensionService and namespace and name defined above in the format of namespace/name.
      extensionService: projectcontour/otel-collector
      # The service name that envoy sends to openTelemetry-collector, the default is contour.
      serviceName: some-service-name
      # The overall sampling rate for tracing, the default is 100.
      overallSampling: 100
      # The client sampling rate for tracing, the default is 100.
      clientSampling: 100
      # The random sampling rate for tracing, the default is 100.
      randomSampling: 100
      # A custom set of tags.
      customTags:
      # envoy will send the tagName to the collector.
      - tagName: custom-tag
        # fixed tag value.
        literal: foo
      - tagName: header-tag
        # The tag value obtained from the request header,
        # if the request header does not exist, this tag will not be sent.
        requestHeaderName: X-Custom-Header
EOF

Install httpbin and test it:

kubectl apply -f https://projectcontour.io/examples/httpbin.yaml

Access the api and view the logs of simplest:

kubectl logs deploy/simplest-collector -n projectcontour

Now you should be able to see traces in the logs of the otel collector.

Trace and span identifiers can also be included in access logs to correlate log entries with traces.