[Request]: Rework Fleet-managed APM Server get started guide

[colleenmcginnis]

Description

Rework the Fleet-managed APM Server get started guide (and the related diagram on the get started page) based on feedback from @eedugon:

Is it mandatory to run the APM integration in the SAME Agent that acts as Fleet server? If so I think we should clearly state this, because a Fleet user with existing Fleet Servers might think that the APM Server integration could run directly in a normal Elastic Agent managed by fleet without being also a Fleet Server.

That's also not described / explained in the Fleet-managed APM Server guide.

About the Step 1 of that guide: https://observability-docs_bk_4599.docs-preview.app.elstc.co/guide/en/observability/master/get-started-with-fleet-apm-server.html#_step_1_set_up_fleet (Setup Fleet):

• Shouldn't we rely and refer to the Fleet documentation for the Fleet Setup (if it's not already done)? Our content could get outdated as the Fleet Server setup is part of the ingest / fleet documentation and there are multiple Deployment models available.

Of course that question is related to the previous one about if a fleet server together with the apm server is mandatory in the fleet managed mode.

In my opinion, and if the Fleet Server in the same agent as the APM Server is not mandatory, we should state that in the docs, also explaining that:

• If the user doesn't have a Fleet Setup then the suggestion is to colocate together the Fleet Server and the APM Server (as it's quicker and simpler).
• If the user already has a Fleet Setup (they could even have multiple Fleet Servers in their environment), they can do any of:
  • Add an agent with the APM Server to act as APM Server
  • Add the APM Server integration to any of their existing fleet servers so they would act as Fleet Servers + APM Servers.

And then add the necessary instructions.

A guide to install a managed APM Server telling you to install a Fleet Server without explaining that you only have to install it if you don't have a fleet setup already in place feels a bit misleading.

See initial feedback from @simitt in #4599 (comment).

Resources

#4599 (comment)

Which documentation set does this change impact?

Stateful only

Feature differences

N/A

What release is this request related to?

N/A

Collaboration model

The documentation team

Point of contact.

Main contact: @eedugon

Stakeholders: @simitt

[eedugon]

Thanks a lot for creating this @colleenmcginnis ! If you want I could work on a proposal for this in the next sprint.

@simitt confirmed that:

• It's not mandatory to run Fleet Server collocated with the APM Server integration, it's just the simplest setup for an environment that doesn't have a Fleet setup already in place. We will highlight that in the docs.

• Then for the fleet setup we will just reference to the fleet deployment models after reviewing if the docs are accurate and we don't miss anything from the existing content.