OTel sampler is by default "AlwaysOn" but the documentation states different

[GFriedrich]

What happened:
The documentation states that the OTel sampler is by default set to "AlwaysOff". But in fact it is "AlwaysOn".

What you expected to happen:
That the documentation aligns with the code.
IMHO it would be best if the code is changed, because a "AlwaysOn" setting can be somewhat heavy in regards to the amount of created traces.

Anything else we need to know:
Default is configured here:

ingress-nginx/internal/ingress/controller/config/config.go

Line 888 in 5ae018e

OtelSampler: "AlwaysOn",

But documentation states something different on these places:

ingress-nginx/docs/user-guide/third-party-addons/opentelemetry.md

Line 79 in 5ae018e

# The available samplers are: AlwaysOn, AlwaysOff, TraceIdRatioBased, Default: AlwaysOff

ingress-nginx/docs/user-guide/nginx-configuration/configmap.md

Line 167 in 5ae018e

| [otel-sampler](#otel-sampler) | string | "AlwaysOff" | |

ingress-nginx/docs/user-guide/nginx-configuration/configmap.md

Line 1049 in 5ae018e

Specifies the sampler to be used when sampling traces. The available samplers are: AlwaysOff, AlwaysOn, TraceIdRatioBased, remote. _**default:**_ AlwaysOff

[strongjz]

@GFriedrich please open a PR to update the the documentation to match reality.

Looks like the docs were not updated when the config was in #9978

[strongjz]

/triage accpeted
/priority backlog

[k8s-ci-robot]

@strongjz: The label(s) triage/accpeted cannot be applied, because the repository doesn't have them.

In response to this:

/triage accpeted
/priority backlog

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[strongjz]

/triage accepted

[GFriedrich]

@strongjz will do.
Just a question: Wouldn't it be better to set the default sampler to TraceIdRatioBased. I feel like setting it to AlwaysOn for somebody who just deploys it and doesn't check on the defaults this can cause quite some pain in regards to load.

[strongjz]

It's already set to always on now, though. We'd have to wait till 1.13 to change it. So you could change it to that and update the docs for a 1.13 release.

[GFriedrich]

@strongjz: Ok then I'll change the default sampler and the documentation. Will work on it on the weekend.