[DOC] Missing documentation for search_pipelines in NodesInfo request section

[lukas-vlcek]

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Tell us about your request. Provide a summary of the request and all versions that are affected.

There seems to be missing documentation for search_pipelines metric parameter in https://opensearch.org/docs/latest/api-reference/nodes-apis/nodes-info/

At least according to code there is such a metric in NodesInfoRequest.Metric enum and public NodeInfo info() in NodeService handles such parameter.

Cc: @msfroh

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.

n/a

[msfroh]

Yup.... this was a miss on my part when the search pipelines feature was added.

It was added to NodesInfo more so that nodes could coordinate amongst themselves (refusing to create a search pipeline unless all data nodes have the relevant processors installed). I forgot that NodesInfo is also user-visible.

[lukas-vlcek]

The thing is that with the change being introduced here I also wanted to provide documentation update. Are you fine with me adding the missing search_pipeline parameter to NodesInfo doc and marking it as not included in the default set of "metrics"?
(Although I think this should be two separated documentation PRs: one to add the search_pipelines parameter, second making it non default)

[msfroh]

That change isn't going to be backported to 2.x because it's a breaking change, right?

In that case, for now, the doc change should just be to add the parameter I think.

Doc team, how are we planning to handle eventual 3.0 docs? I've kind of assumed that we're treating that as a "worry about it tomorrow problem" (but I like procrastinating).

[lukas-vlcek]

@msfroh There are two parts.

1. Missing search_pipelines parameter in the docs. When added it is relevant to 2.x as well, so it should be beckported if I understand correctly (I am also not sure what is the versioning story for docs).
2. Taking search_pipelines out of the default set of "metrics" (which will apply to some other "metrics" added in the future too, like node_analyzers). This will not go to 2.x.

That is why I talk about two PRs ... but again, I am not sure about the versioning strategy for docs at the moment.

[hdhalter]

Hi @lukas-vlcek , @msfroh , agreed, It sounds like two different PRs. We are updating the documentation for only the latest version of 2.x, which currently is 2.12. So, we can update the search_pipelines parameter there. can also create PRs for future (e.g., 3.0) documentation and just label it as 3.0 so we know not to merge it.