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X-Ray Instrumentation and Concepts

  • Instrumentation means the measure of product's performance, diagnose errors, and to write trace information.

  • To instrument your application code, you use the X-Ray SDK

  • Many SDK require only configuration changes
  • YHou can modify your application code to customize and annotate the data that the SDK sends to X-Ray, using interceptors, filters, handlers, middleware.

Concepts

  • Segments: each application / service will send them
  • Subsegments: if you need more details in your segment
  • Trace: segments collected together to form an end-to-end trace
  • Sampling: decrease the amount of requests sent to X-Ray, reduce cost
  • Annotations: Key Value pairs used to index traces and use with filters

  • Metadata: Key Value pairs, not indexed, not used for searching

  • The X-Ray deaemon / agent has a config to send traces cross account:

    • make sure the IAM permissions are correct - the agent will assume the role.
    • This allows to have a central account for all your application tracing.

Sampling Rules

  • With sampling rules, you control the amount of data that you record

  • You can modify sampling rules without changing your code

  • By default, the X-Ray SDK records the first request each second, and five percent of any additional requests

  • One request per second is the reservoir, which ensures that at least one trace is reacorded each second as long the service is serving requests.
  • Five percent is the rate which additional requests beyond the reservoir size are sampled.

You can create your own rules with the reservoir and rate.