[Issue]: When using ES Remote Output, Fleet Server is used to test the connectivity to the remote ES cluster

[lucabelluccini]

Type of issue

Missing information

What documentation page is affected

https://www.elastic.co/docs/reference/fleet/remote-elasticsearch-output

What happened?

When using Elasticsearch Remote Output, Fleet Server will test a connection to the configured Elasticsaerch remote output.

I do not know which one of the Fleet Servers is used to perform the test.

The result of the test, successful or not, will be written into logs-fleet_server.output_health-default data stream.

The connectivity test result will be used to report the ES Remote output as Healthy or Unhealthy in the Fleet > Settings > Outputs page (under Status).

This test is not obvious and possibly misleading.

We're assuming that Fleet Server would be able to connect to the Remote Elasticsearch Output, while the destination ES output for data can be in a totally different network which would be reachable ONLY from a set of Elastic Agents, but not Fleet Server.

We should warn about this health check being done behind the scenes and it can be ignored if it is expected that Fleet Server is unable to reach the Remote ES output.

Additional info

At least in 8.17, this is not preventing the ES remote output to be used, but the Unhealthy tag and the banner on the page might be very confusing.

[lucabelluccini]

Related elastic/fleet-server#4185

[kilfoyle]

@lucabelluccini Sorry for the delay with this one! Here's a pull request to add a warning to the remote ES docs page:
#1307

[lucabelluccini]

No worries @kilfoyle - I've left a comment on the PR.