[Elastic Agent] Do not watch monitors

[michalpristas]

What does this PR do?

WHen monitors were enabled monitoring of simple filebeat and metricbeat was configured and should not.
This resulted in socket not found because metricbeat was told to keep an eye on metricbeat.sock but it was not available as simple metricbeat was not running.

This PR does not configure monitoring beat to watch for simple beat if simple beat is not actually running

Why is it important?

Fixes: #27127

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

[elasticmachine]

Pinging @elastic/agent (Team:Agent)

[ruflin]

What you mean by "simple" *beat above? Is this the metricbeat that monitors the other processes?

What happens in 7.14 without this fix? Do errors only show up in logs or are there further side effects?

[michalpristas]

just errors in logs.
and this is only if you run fleet server only with monitoring enabled, without any system or any other integration which would start filebeat and make error disappear.
without this fix probably nothing happens as on cloud we run fleet server without monitoring
and locally you usually dont run fleet server alone.

by simple i mean the one which is configured to collect configured metrics via configuration/integrations. not the one which monitors agent and its processes. naming is hard but i could not think about other way how to differentiate.

[elasticmachine]

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• Start Time: 2021-08-02T13:47:11.598+0000

• Duration: 82 min 36 sec

• Commit: e8bf87a

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[blakerouse]

I believe this is the same issue @michel-laterman was looking at. I thought it was fleet-server bootstrap doing the wrong thing, this might actually fix his issue as well.

[blakerouse]

Looks good.

I think this should go to 7.14, if still possible.