Docs feedback: /grafana-agent/tail-based-sampling.md

[lionelmarksgrafana]

The "Quickstart" and "Example" show two different styles of declaring the tailbased sampling policies. It is very challenging to understand why these two different configs are suggested without explaination as to why the syntax is different and for what purpose. The Examples section adds the key "-type" before the sampling policy.. why are these two different..?

[Quickstart]
traces:
configs:
- name: default
...
tail_sampling:
policies:
# sample traces that have a total duration longer than 100ms
- latency:
threshold_ms: 100
# sample traces that contain at least one span with status code ERROR
- status_code:
status_codes:
- "ERROR"

[Examples]
traces:
configs:
- name: default
...
tail_sampling:
policies:
- type: latency
latency:
threshold_ms: 100
- type: status_code
status_code:
status_codes:
- "ERROR"

[joe-elliott]

I am also confused by how to configure this feature. It's based on the otel collector processor:

https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/processor/tailsamplingprocessor

Honestly we should likely remove our docs on this feature and link back to the Grafana Agent which would likely be more up to date.

[github-actions]

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[hedss]

Coming back to this, the tail sampler in the OTel Collector actually started enforcing specific types for policy creation, this is also now reflected in the updated blog post: https://grafana.com/blog/2022/05/11/an-introduction-to-trace-sampling-with-grafana-tempo-and-grafana-agent/

The other consideration here is that Flow/River is now the default methodology for configuring the Agent. We now have a new issue for configuring the agent #2330 which will move them to the Agent.