Profiling: Updates to troubleshooting

[christos68k]

Summary

1. Replaced references to APM server with 'Collector'
2. Added troubleshooting for newer HA connecting to older cluster

[github-actions]

A documentation preview will be available soon:

• 📚 HTML diff
• 📙 Observability Guide

[mergify]

This pull request does not have a backport label. Could you fix it @christos68k? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-/d./d is the label to automatically backport to the /d./d branch. /d is the digit
  NOTE: backport-skip has been added to this pull request.

[mdbirnstiehl]

Just a couple of capitalization suggestions. Otherwise, LGTM.

[bmorelli25]

Before we merge this— @christos68k I haven't heard of APM Server being renamed to "Collector". Do you know where that decision came from?

[bmorelli25]

Never mind, I found the internal issue. LGTM!

[christos68k]

Never mind, I found the internal issue. LGTM!

To clarify, AFAIK the APM server has not been renamed. This PR reflects the fact that we started running the profiling collector as a standalone process inside the integration server. Previously, it was part of the APM server codebase and was running inside the APM server process.

[bmorelli25]

To clarify, AFAIK the APM server has not been renamed. This PR reflects the fact that we started running the profiling collector as a standalone process inside the integration server. Previously, it was part of the APM server codebase and was running inside the APM server process.

Thanks. This is why I was confused initially—I thought the APM Server had been renamed, and I hadn't heard anything about that.

[iogbole]

LGTM

[christos68k]

@bmorelli25 Feel free to merge this (or trigger a new check run), I can't re-trigger the checks.

[mdbirnstiehl]

@elasticmachine, run elasticsearch-ci/docs