`host.name` assigned with `pod.name`

[crespocarlos]

Describe the bug

When viewing the Hosts UI with Ruby APM service active in a k8s pod, Ruby agent monitored services report the pod name in the host.name, which makes the Hosts View display hosts that do not correlate with hosts monitored by the system integration.

Steps to reproduce

• Run a ruby APM instrumented service in a k8s pod
• Ingest that into ES
• Open the Infra UI

edge-oblt can be used for the above.

Expected behavior

Only hosts (VMs) are expected to be present in the Hosts View.

Additional context

There was a ticket opened for this issue, but apparently, the problem persists: https://github.com/elastic/apm-agent-ruby/issues/1292

Sample doc

{
  "_index": ".ds-metrics-apm.internal-default-2024.07.17-000005",
  "_id": "_PQbxZABSDGMOSNlRFmU",
  "_score": 0,
  "_source": {
    "agent": {
      "name": "ruby",
      "version": "4.7.3"
    },
    "cloud": {
      "availability_zone": "us-central1-c",
      "instance": {
        "id": "899642394284519665",
        "name": "gke-edge-oblt-edge-oblt-pool-8fc2868f-vmqk"
      },
      "machine": {
        "type": "e2-highcpu-4"
      },
      "project": {
        "id": "elastic-observability"
      },
      "provider": "gcp",
      "region": "us-central1"
    },
    "data_stream": {
      "dataset": "apm.internal",
      "namespace": "default",
      "type": "metrics"
    },
    "host": {
      "architecture": "x86_64",
      "hostname": "opbeans-ruby-ccb6447c9-4srwm",
      "ip": "34.66.231.196",
      "name": "opbeans-ruby-ccb6447c9-4srwm",
      "os": {
        "platform": "linux"
      }
    },
    "metricset": {
      "name": "span_breakdown"
    }
  }
}

[crespocarlos]

I had a quick call with @Mpdreamz , and he explained that the non-matching host names shipped by APM agents are due to missing configuration as exemplified in this comment https://github.com/elastic/observability-dev/issues/3321#issuecomment-2236909682.