# 0025: Container Metric Fields
<!-- Leave this ID at 0000. The ECS team will assign a unique, contiguous RFC number upon merging the initial stage of this RFC. -->

- Stage: **3 (finished)** <!-- Update to reflect target stage. See https://elastic.github.io/ecs/stages.html -->
- Date: **2022-03-03** <!-- The ECS team sets this date at merge time. This is the date of the latest stage advancement. -->

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Stage 0: Provide a high level summary of the premise of these changes. Briefly describe the nature, purpose, and impact of the changes. ~2-5 sentences.
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This RFC proposes 6 additional container metric fields into ECS for monitoring
container CPU, memory, disk and network performance:
- container.cpu.usage
- container.memory.usage
- container.network.ingress.bytes
- container.network.egress.bytes
- container.disk.read.bytes
- container.disk.write.bytes

With existing metadata fields `container.id`, `container.image.name`, `container.image.tag`,
`container.labels`, `container.name` and `container.runtime`, these total 12
fields will become the common field schema for container metrics. These metric
fields and metadata fields are recommended or required for all events related to
containers.

## Fields

This RFC calls for the addition of metric fields to collect basic monitoring
metrics from a container such as CPU, memory, network and disk.
Please see [`container.yml`](0000/container.yml) for definitions of all fields.

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## Usage

Container metric fields and container metadata fields can be collected from
several sources. For example, a user who uses both Docker, Cloudfoundry
and AWS Fargate would like to collect data regarding all containers and store
them in a centralized location. Without these new container metric fields,
Metricbeat is reporting container metrics under different names from different
sources. For example, for CPU usage, `docker.cpu.total.pct` is used. For
Cloudfoundry, `cloudfoundry.container.cpu.pct` is used and for AWS Fargate,
`awsfargate.task_stats.cpu.total.pct` is used.
With these different field names, Kibana Docker containers metrics UI can only
display data collected from Docker but no other sources.

With the additional container metric fields proposed here, users should be able
to see the same metric field collected from different sources and Kibana should
be able to display all containers, not only from Docker, but also Cloudfoundry,
AWS Fargate and etc.

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Stage 1: Describe at a high-level how these field changes will be used in practice. Real world examples are encouraged. The goal here is to understand how people would leverage these fields to gain insights or solve problems. ~1-3 paragraphs.
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## Source data

- Docker
- Kubernetes
- AWS Fargate
- Cloudfoundry
- Google GKE
- Containerd

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### Kubernetes

#### Original log

```json
{
  "node": {
    "nodeName": "gke-beats-default-pool-a5b33e2e-hdww",
    "systemContainers": [
      {
        "name": "kubelet",
        "startTime": "2021-12-20T09:53:30.156Z",
        "cpu": {
          "time": "2021-12-20T09:53:30.156Z",
          "usageNanoCores": 11263994,
          "usageCoreNanoSeconds": 2357800908948
        },
        "memory": {
          "time": "2021-12-20T09:53:30.156Z",
          "usageBytes": 36683776,
          "workingSetBytes": 36495360,
          "rssBytes": 35512320,
          "pageFaults": 100835242,
          "majorPageFaults": 0
        },
        "userDefinedMetrics": null
      }
    ],
    "startTime": "2021-12-20T09:53:30.156Z",
    "cpu": {
      "time": "2021-12-20T09:53:30.156Z",
      "usageNanoCores": 18691146,
      "usageCoreNanoSeconds": 4189523881380
    },
    "memory": {
      "time": "2021-12-20T09:53:30.156Z",
      "availableBytes": 1768316928,
      "usageBytes": 2764943360,
      "workingSetBytes": 2111090688,
      "rssBytes": 2150400,
      "pageFaults": 131567,
      "majorPageFaults": 103
    },
    "network": {
      "time": "2021-12-20T09:53:30.156Z",
      "rxBytes": 1115133198,
      "rxErrors": 0,
      "txBytes": 812729002,
      "txErrors": 0
    },
    "fs": {
      "availableBytes": 98727014400,
      "capacityBytes": 101258067968,
      "usedBytes": 2514276352,
      "inodesFree": 18446744073709551615,
      "inodes": 6258720,
      "inodesUsed": 138624
    },
    "runtime": {
      "imageFs": {
        "availableBytes": 98727014400,
        "capacityBytes": 101258067968,
        "usedBytes": 860204379,
        "inodesFree": 18446744073709551615,
        "inodes": 6258720,
        "inodesUsed": 138624
      }
    }
  },
  "pods": [
    {
      "podRef": {
        "name": "nginx-deployment-2303442956-pcqfc",
        "namespace": "default",
        "uid": "beabc196-2456-11e7-a3ad-42010a840235"
      },
      "startTime": "2021-12-20T09:53:30.156Z",
      "containers": [
        {
          "name": "nginx",
          "startTime": "2017-04-18T16:47:44Z",
          "cpu": {
            "time": "2017-04-20T08:06:34Z",
            "usageNanoCores": 11263994,
            "usageCoreNanoSeconds": 43959424
          },
          "memory": {
            "time": "2017-04-20T08:06:34Z",
            "usageBytes": 1462272,
            "workingSetBytes": 1454080,
            "rssBytes": 1409024,
            "pageFaults": 841,
            "majorPageFaults": 0
          },
          "rootfs": {
            "availableBytes": 98727014400,
            "capacityBytes": 101258067968,
            "usedBytes": 61440,
            "inodesFree": 6120096,
            "inodes": 6258720,
            "inodesUsed": 21
          },
          "logs": {
            "availableBytes": 98727014400,
            "capacityBytes": 101258067968,
            "usedBytes": 28672,
            "inodesFree": 6120096,
            "inodes": 6258720,
            "inodesUsed": 138624
          },
          "userDefinedMetrics": null
        }
      ],
      "network": {
        "time": "2021-12-20T09:53:30.156Z",
        "rxBytes": 107056,
        "rxErrors": 0,
        "txBytes": 72447,
        "txErrors": 0
      },
      "volume": [
        {
          "availableBytes": 1939689472,
          "capacityBytes": 1939701760,
          "usedBytes": 12288,
          "inodesFree": 473551,
          "inodes": 473560,
          "inodesUsed": 9,
          "name": "default-token-sg8x5"
        }
      ]
    }
  ]
}
```

#### Mapped event

```json
{
  "container": {
    "cpu.usage":          0.005631997,
    "memory.usage":       0.01,
    "name": "nginx",
    "network.ingress.bytes": 107056,
    "network.egress.bytes": 72447
  },
  "kubernetes": {
    "container": {
      "start_time": "2021-12-20T09:53:30.156Z",
      "memory": {
        "rss": {
          "bytes": 1409024
        },
        "majorpagefaults": 0,
        "usage": {
          "node": {
            "pct": 0.01
          },
          "bytes": 1462272,
          "limit": {
            "pct": 0.1
          }
        },
        "available": {
          "bytes": 0
        },
        "workingset": {
          "bytes": 1454080,
          "limit": {
            "pct": 0.09943977591036414
          }
        },
        "pagefaults": 841
      },
      "rootfs": {
        "inodes": {
          "used": 21
        },
        "available": {
          "bytes": 98727014400
        },
        "used": {
          "bytes": 61440
        },
        "capacity": {
          "bytes": 101258067968
        }
      },
      "name": "nginx",
      "cpu": {
        "usage": {
          "core": {
            "ns": 43959424
          },
          "node": {
            "pct": 0.005631997
          },
          "limit": {
            "pct": 0.005631997
          },
          "nanocores": 11263994
        }
      },
      "logs": {
        "inodes": {
          "count": 13107200,
          "used": 2,
          "free": 10806621
        },
        "available": {
          "bytes": 138514030592
        },
        "used": {
          "bytes": 446464
        },
        "capacity": {
          "bytes": 211108732928
        }
      }
    }
  },
  "@timestamp": "2021-12-20T09:53:30.156Z",
  "ecs": {
    "version": "8.0.0"
  },
  "metricset": {
    "period": 10000,
    "name": "container"
  },
  "event": {
    "duration": 156057406,
    "agent_id_status": "verified",
    "ingested": "2021-12-20T09:53:30Z",
    "module": "kubernetes",
    "dataset": "kubernetes.container"
  }
}
```

### Docker

#### Original log

```json
{
  "blkio_stats": {
    "io_merged_recursive": [],
    "io_queue_recursive": [],
    "io_service_bytes_recursive": [
      {
        "major": 8,
        "minor": 0,
        "op": "Read",
        "value": 311296
      },
      {
        "major": 8,
        "minor": 0,
        "op": "Write",
        "value": 283956224
      },
      {
        "major": 8,
        "minor": 0,
        "op": "Sync",
        "value": 284267520
      },
      {
        "major": 8,
        "minor": 0,
        "op": "Async",
        "value": 0
      },
      {
        "major": 8,
        "minor": 0,
        "op": "Discard",
        "value": 0
      },
      {
        "major": 8,
        "minor": 0,
        "op": "Total",
        "value": 284267520
      },
      {
        "major": 253,
        "minor": 0,
        "op": "Read",
        "value": 311296
      },
      {
        "major": 253,
        "minor": 0,
        "op": "Write",
        "value": 283956224
      },
      {
        "major": 253,
        "minor": 0,
        "op": "Sync",
        "value": 284267520
      },
      {
        "major": 253,
        "minor": 0,
        "op": "Async",
        "value": 0
      },
      {
        "major": 253,
        "minor": 0,
        "op": "Discard",
        "value": 0
      },
      {
        "major": 253,
        "minor": 0,
        "op": "Total",
        "value": 284267520
      }
    ],
    "io_service_time_recursive": [],
    "io_serviced_recursive": [
      {
        "major": 8,
        "minor": 0,
        "op": "Read",
        "value": 10
      },
      {
        "major": 8,
        "minor": 0,
        "op": "Write",
        "value": 3469
      },
      {
        "major": 8,
        "minor": 0,
        "op": "Sync",
        "value": 3479
      },
      {
        "major": 8,
        "minor": 0,
        "op": "Async",
        "value": 0
      },
      {
        "major": 8,
        "minor": 0,
        "op": "Discard",
        "value": 0
      },
      {
        "major": 8,
        "minor": 0,
        "op": "Total",
        "value": 3479
      },
      {
        "major": 253,
        "minor": 0,
        "op": "Read",
        "value": 10
      },
      {
        "major": 253,
        "minor": 0,
        "op": "Write",
        "value": 2394
      },
      {
        "major": 253,
        "minor": 0,
        "op": "Sync",
        "value": 2404
      },
      {
        "major": 253,
        "minor": 0,
        "op": "Async",
        "value": 0
      },
      {
        "major": 253,
        "minor": 0,
        "op": "Discard",
        "value": 0
      },
      {
        "major": 253,
        "minor": 0,
        "op": "Total",
        "value": 2404
      }
    ],
    "io_time_recursive": [],
    "io_wait_time_recursive": [],
    "sectors_recursive": []
  },
  "cpu_stats": {
    "cpu_usage": {
      "percpu_usage": [
        8989285945449,
        8802991575246,
        8723071634953,
        8812077512624
      ],
      "total_usage": 35327426668272,
      "usage_in_kernelmode": 2720580000000,
      "usage_in_usermode": 32477900000000
    },
    "online_cpus": 4,
    "system_cpu_usage": 7640294590000000,
    "throttling_data": {
      "periods": 0,
      "throttled_periods": 0,
      "throttled_time": 0
    }
  },
  "id": "86a4d10d07bf0b1ded54c7156b4362e8b0dba9d450201a9695b4714c1492829c",
  "memory_stats": {
    "limit": 15620788224,
    "max_usage": 420536320,
    "stats": {
      "active_anon": 59502592,
      "active_file": 63746048,
      "cache": 194330624,
      "dirty": 0,
      "hierarchical_memory_limit": 9223372036854771712,
      "hierarchical_memsw_limit": 9223372036854771712,
      "inactive_anon": 60268544,
      "inactive_file": 130256896,
      "mapped_file": 123408384,
      "pgfault": 37852947,
      "pgmajfault": 0,
      "pgpgin": 25772802,
      "pgpgout": 25697155,
      "rss": 119738368,
      "rss_huge": 4194304,
      "total_active_anon": 59502592,
      "total_active_file": 63746048,
      "total_cache": 194330624,
      "total_dirty": 0,
      "total_inactive_anon": 60268544,
      "total_inactive_file": 130256896,
      "total_mapped_file": 123408384,
      "total_pgfault": 37852947,
      "total_pgmajfault": 0,
      "total_pgpgin": 25772802,
      "total_pgpgout": 25697155,
      "total_rss": 119738368,
      "total_rss_huge": 4194304,
      "total_unevictable": 0,
      "total_writeback": 0,
      "unevictable": 0,
      "writeback": 0
    },
    "usage": 326488064
  },
  "name": "/elastic-package-stack_elastic-agent_1",
  "networks": {
    "eth0": {
      "rx_bytes": 23962833,
      "rx_dropped": 0,
      "rx_errors": 0,
      "rx_packets": 128811,
      "tx_bytes": 593646535,
      "tx_dropped": 0,
      "tx_errors": 0,
      "tx_packets": 186477
    }
  },
  "num_procs": 0,
  "pids_stats": {
    "current": 68
  },
  "precpu_stats": {
    "cpu_usage": {
      "percpu_usage": [
        8989283978798,
        8802978152064,
        8723042900675,
        8812068229234
      ],
      "total_usage": 35327373260771,
      "usage_in_kernelmode": 2720550000000,
      "usage_in_usermode": 32477870000000
    },
    "online_cpus": 4,
    "system_cpu_usage": 7640290600000000,
    "throttling_data": {
      "periods": 0,
      "throttled_periods": 0,
      "throttled_time": 0
    }
  },
  "preread": "2021-02-04T22:02:38.129030814Z",
  "read": "2021-02-04T22:02:39.138448063Z",
  "storage_stats": {}
}
```

#### Mapped event by docker.cpu dataset

Event contains `container` fields identifying the container and its runtime. This sample event also contains a summary of the CPU metrics in `container.cpu`.
```json
{
  "@timestamp": "2017-10-12T08:05:34.853Z",
  "container": {
    "id": "7f3ca1f1b2b310362e90f700d2b2e52ebd46ef6ddf10c0704f22b25686c466ab",
    "image": {
      "name": "metricbeat_beat"
    },
    "name": "metricbeat_beat_run_8ba23fa682a6",
    "runtime": "docker",
    "cpu": {
      "usage": 0.015459536757425743
    }
  },
  "docker": {
    "cpu": {
      "kernel": {
        "norm": {
          "pct": 0.007425742574257425
        },
        "pct": 0.0594059405940594,
        "ticks": 26810000000
      },
      "system": {
        "norm": {
          "pct": 1
        },
        "pct": 8,
        "ticks": 65836400000000
      },
      "total": {
        "norm": {
          "pct": 0.015459536757425743
        },
        "pct": 0.12367629405940594
      },
      "user": {
        "norm": {
          "pct": 0.006188118811881188
        },
        "pct": 0.04950495049504951,
        "ticks": 35720000000
      }
    }
  },
  "event": {
    "dataset": "docker.cpu",
    "duration": 115000,
    "module": "docker"
  },
  "metricset": {
    "name": "cpu",
    "period": 10000
  },
  "service": {
    "address": "/var/run/docker.sock",
    "type": "docker"
  }
}
```

#### Mapped event by docker.memory dataset
Event contains `container` fields identifying the container and its runtime. This sample event also contains a summary of the memory metrics in `container.memory`.
```json
{
    "@timestamp": "2017-10-12T08:05:34.853Z",
    "container": {
        "id": "aa41902101351f415e6e983b0673c0ba715dd4bc316bd5fc0ebd6fcf94287f86",
        "image": {
            "name": "redis:latest"
        },
        "name": "amazing_cohen",
        "runtime": "docker",
        "memory": {
          "usage": 0.000672283359618831
        }
    },
    "docker": {
        "memory": {
            "fail": {
                "count": 0
            },
            "limit": 2095878144,
            "rss": {
                "pct": 0.0004025882909345325,
                "total": 843776
            },
            "stats": {
                "active_anon": 421888,
                "active_file": 36864,
                "cache": 86016,
                "dirty": 0,
                "hierarchical_memory_limit": 9223372036854771712,
                "hierarchical_memsw_limit": 9223372036854771712,
                "inactive_anon": 421888,
                "inactive_file": 49152,
                "mapped_file": 53248,
                "pgfault": 1587,
                "pgmajfault": 1,
                "pgpgin": 2426,
                "pgpgout": 2199,
                "rss": 843776,
                "rss_huge": 0,
                "total_active_anon": 421888,
                "total_active_file": 36864,
                "total_cache": 86016,
                "total_dirty": 0,
                "total_inactive_anon": 421888,
                "total_inactive_file": 49152,
                "total_mapped_file": 53248,
                "total_pgfault": 1587,
                "total_pgmajfault": 1,
                "total_pgpgin": 2426,
                "total_pgpgout": 2199,
                "total_rss": 843776,
                "total_rss_huge": 0,
                "total_unevictable": 0,
                "total_writeback": 0,
                "unevictable": 0,
                "writeback": 0
            },
            "usage": {
                "max": 7860224,
                "pct": 0.000672283359618831,
                "total": 1409024
            }
        }
    },
    "event": {
        "dataset": "docker.memory",
        "duration": 115000,
        "module": "docker"
    },
    "metricset": {
        "name": "memory"
    },
    "service": {
        "address": "/var/run/docker.sock",
        "type": "docker"
    }
}
```

#### Mapped event by docker.network dataset
Event contains `container` fields identifying the container and its runtime. This sample event also contains a summary of the network metrics in `container.network`.
```json
{
    "@timestamp": "2017-10-12T08:05:34.853Z",
    "agent": {
        "hostname": "host.example.com",
        "name": "host.example.com"
    },
    "container": {
      "id": "cc78e58acfda4501105dc4de8e3ae218f2da616213e6e3af168c40103829302a",
      "image": {
        "name": "metricbeat_elasticsearch"
      },
      "name": "metricbeat_elasticsearch_1_df866b3a7b3d",
      "runtime": "docker",
      "network": {
        "ingress": {
          "bytes": 23047
        },
        "egress": {
          "bytes": 0
        }
      }
    },
    "docker": {
        "network": {
            "in": {
                "bytes": 0,
                "dropped": 0,
                "errors": 0,
                "packets": 0
            },
            "inbound": {
                "bytes": 23047,
                "dropped": 0,
                "errors": 0,
                "packets": 241
            },
            "interface": "eth0",
            "out": {
                "bytes": 0,
                "dropped": 0,
                "errors": 0,
                "packets": 0
            },
            "outbound": {
                "bytes": 0,
                "dropped": 0,
                "errors": 0,
                "packets": 0
            }
        }
    },
    "event": {
        "dataset": "docker.network",
        "duration": 115000,
        "module": "docker"
    },
    "metricset": {
        "name": "network"
    },
    "service": {
        "address": "/var/run/docker.sock",
        "type": "docker"
    }
}
```

## Scope of impact

<!--
Stage 2: Identifies scope of impact of changes. Are breaking changes required? Should deprecation strategies be adopted? Will significant refactoring be involved? Break the impact down into:
 * Ingestion mechanisms (e.g. beats/logstash)
 * Usage mechanisms (e.g. Kibana applications, detections)
 * ECS project (e.g. docs, tooling)
The goal here is to research and understand the impact of these changes on users in the community and development teams across Elastic. 2-5 sentences each.
-->

This is a new field set, and the changes introduced will not affect existing ECS implementations.

Integrations or other data sources mapping to ECS will need to map their original events to the new fields as well.

The new field names will allow Kibana Docker containers metrics UI to
display data collected from different container sources, therefore it should be renamed to
a more generic title.
Currently, it can only display data from Docker.
## Concerns

<!--
Stage 1: Identify potential concerns, implementation challenges, or complexity. Spend some time on this. Play devil's advocate. Try to identify the sort of non-obvious challenges that tend to surface later. The goal here is to surface risks early, allow everyone the time to work through them, and ultimately document resolution for posterity's sake.
-->

We need to carefully define each field because when collecting these container
metrics from different sources, the scope of these metrics change. We should
make sure when users are using these metrics, they are all collected to represent
the same thing. For example, `container.cpu.usage` needs to be a normalized value
between 0 and 1.

We need to carefully distinguish metrics of containers with the metrics coming from the host
where these containers are running. For example, events from Kubernetes contain information for
both the container and the host(kubernetes node)(e.g., `container.id` and `host.id`).
For that reason host metrics should be stored under `host.*` while container metrics should be stored
under `container.*`.

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## People

The following are the people that consulted on the contents of this RFC.

* @kaiyan-sheng | author
* @cyrille-leclerc | sponsor
* @jsoriano | subject matter expert

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* @Yasmina | author
* @Monique | sponsor
* @EunJung | subject matter expert
* @JaneDoe | grammar, spelling, prose
* @Mariana
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## References

Common Fields for Container Inventory Schema: https://github.com/elastic/beats/issues/22179

### RFC Pull Requests

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* Stage 0: https://github.com/elastic/ecs/pull/1441
    * Stage 0 date correction: https://github.com/elastic/ecs/pull/1447

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* Stage 1: https://github.com/elastic/ecs/pull/1529

* Stage 2: https://github.com/elastic/ecs/pull/1747