ingest: document index.default_pipeline

[jakelandis]

No description provided.

[elasticmachine]

Pinging @elastic/es-core-infra

[original-brownbear]

LGTM

[jakelandis]

@original-brownbear - I forgot to call out this option in the ingest node documentation.

Can you please take another look ?
Specifically 66f033c (I rendered the doc and the link works fine)

[original-brownbear]

Still LGTM :)

[rjernst]

Is the override of pipeline=_none mentioned somewhere already?

[jakelandis]

@rjernst

Is the override of pipeline=_none mentioned somewhere already?

Nope, it isn't mentioned. I can add to this PR.

how about:

 `index.default_pipeline`::
    The default <<ingest,ingest node>> pipeline for this index. Index requests will fail
    if the default pipeline is set and the pipeline does not exist. The default may be 
    be ignored per request by setting the request parameter `pipeline=_none`. 

[jakelandis]

Updated PR to include mention of pipeline=_none.

[rjernst]

Looks good, one suggestion.

[rjernst]

I suggestion something like this in place of the last sentence:

The default may be overridden using the `pipeline` parameter. The special pipeline name `_none` indicates no ingest pipeline should be run.

The point is to show that pipeline can be specified in general to override the default, and that _none is just a special pipeline name.

[jakelandis]

6.5 backport: e0ee802