apm[monitoring]: update monitor mappsing to include new TBS metrics

[rubvs]

• Have you signed the contributor license agreement?
• Have you followed the contributor guidelines?
• If submitting code, have you built your formula locally prior to submission with gradle check?
• If submitting code, is your pull request against main? Unless there is a good reason otherwise, we prefer pull requests against main and will backport as needed.
• If submitting code, have you checked that your submission is for an OS and architecture that we support?
• If you are submitting this code for a class then read our policy for that.

Context

• Part of Issue: monitoring: expose storage limit and disk metrics for TBS monitoring apm-server#15533
• Related PR:
  • add tbs storage limit and disk-related metrics apm-server#19568

Test 1: Index Mappings

Test the mappings defined in monitoring-beats.json

1. Build Docker Image

> cd $HOME/src/elasticsearch

# Build the ES image with the added metric mappings.
> ./gradlew buildAarch64DockerImage

2. Update APM Server Docker Compose

Edit apm-server/docker-compose.yml and change the ES image.

> cd $HOME/src/apm-server

elasticsearch:
 image: docker.elastic.co/elasticsearch/elasticsearch:9.3.0-custom-SNAPSHOT
 # ... rest of config

3. Spin Up Stack

> cd $HOME/src/apm-server

# Spin up the stack
> docker-compose up

4. Test Mappings

• Check that connection to ES is properly setup

> curl -u admin:changeme http://localhost:9200

{
  "name" : "834c14dc8da6",
  "cluster_name" : "docker-cluster",
  "cluster_uuid" : "eT_LqP39R9icHdV5mmiMyg",
  "version" : {
    "number" : "9.3.0-SNAPSHOT",
    "build_flavor" : "default",
    "build_type" : "docker",
    "build_hash" : "47bb1a66844e9c601a68569b102b803512203697",
    "build_date" : "2025-11-14T15:37:45.019895Z",
    "build_snapshot" : true,
    "lucene_version" : "10.3.1",
    "minimum_wire_compatibility_version" : "8.19.0",
    "minimum_index_compatibility_version" : "8.0.0"
  },
  "tagline" : "You Know, for Search"
}

• Go the the Kibana UI via http://127.0.0.1:5601 and check the mappings in Dev Tools

# List the index
GET _cat/indices/.monitoring-beats-7-*?h=index

 .monitoring-beats-7-2025.11.14

# View index content
GET .monitoring-beats-7-2025.11.14/_mapping?filter_path=**.storage

{
  ".monitoring-beats-7-2025.11.14": {
    "mappings": {
      "properties": {
        "beats_stats": {
          "properties": {
            "metrics": {
              "properties": {
                "apm-server": {
                  "properties": {
                    "sampling": {
                      "properties": {
                        "tail": {
                          "properties": {
                            "storage": {
                              "properties": {
                                "disk_total": {
                                  "type": "long"
                                },
                                "disk_usage_threshold": {
                                  "type": "long"
                                },
                                "disk_used": {
                                  "type": "long"
                                },
                                "lsm_size": {
                                  "type": "long"
                                },
                                "storage_limit": {
                                  "type": "long"
                                },
                                "value_log_size": {
                                  "type": "long"
                                }
                              }
                            }
                          }
                        }
                      }
                    }
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}