Statistics

• Downstream:
  • Downstream statistics relate to incoming connections/requests. They are emitted by listeners, the HTTP connection manager, the TCP proxy filter, etc.
• Upstream:
  • Upstream statistics relate to outgoing connections/requests. They are emitted by connection pools, the router filter, the TCP proxy filter, etc.
• Server:
  • Server statistics describe how the Envoy server instance is working. Statistics like server uptime or amount of allocated memory are categorized here.

Envoy emits three types of values as statistics:

Counters, Gauges, Histograms

Access logging

Access log filters

Access logging sinks

File

Async IO and Customizable log format

gRPC

Stdoutput & Stderror

Tracing

Request ID generation: populate the x-request-id

Client trace ID joining: The x-client-trace-id header can be used to join untrusted request IDs to the trusted internal x-request-id.

External trace service integration:

• External tracers which are part of the Envoy code base, LightStep, Zipkin or Zipkin compatible backends(Jaeger), Datadog and Skywalking
• External tracers which come as a third party plugin, e.g. Instana

How to initiate a trace