--- title: Docker Tag Extraction description: >- Configure automatic tag extraction from Docker container labels and environment variables breadcrumbs: >- Docs > Containers > Docker Agent for Docker, containerd, and Podman > Docker Tag Extraction --- # Docker Tag Extraction ## Overview{% #overview %} The Datadog Agent can create and assign tags to all metrics, traces, and logs emitted by a container based on its labels or environment variables. If you are running the Agent as a binary on a host, configure your tag extractions with the Agent tab instructions. If you are running the Agent as a container, configure your tag extraction with the Containerized Agent tab instructions. ### Out-of-the-box tagging{% #out-of-the-box-tagging %} The Agent can autodiscover and attach tags to all data emitted by containers. The list of tags attached depends on the Agent [cardinality configuration](https://docs.datadoghq.com/agent/docker/tag.md#extract-environment-variables-as-tags). [Tag Cardinality](https://docs.datadoghq.com/getting_started/tagging/assigning_tags.md?tab=containerizedenvironments#tags-cardinality) can impact billing as different cardinality settings impact the number of emitted metrics. | Tag | Cardinality | Requirement | | -------------------- | ------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `container_name` | High | N/A**Note**: not included for the containerd runtime. | | `container_id` | High | N/A | | `rancher_container` | High | Rancher environment | | `mesos_task` | Orchestrator | Mesos environment | | `docker_image` | Low | N/A**Note**: not included for the containerd runtime. | | `image_name` | Low | N/A | | `short_image` | Low | N/A | | `image_tag` | Low | N/A | | `swarm_service` | Low | Swarm environment | | `swarm_namespace` | Low | Swarm environment | | `rancher_stack` | Low | Rancher environment | | `rancher_service` | Low | Rancher environment | | `env` | Low | [Unified service tagging](https://docs.datadoghq.com/getting_started/tagging/unified_service_tagging.md) enabled | | `version` | Low | [Unified service tagging](https://docs.datadoghq.com/getting_started/tagging/unified_service_tagging.md) enabled | | `service` | Low | [Unified service tagging](https://docs.datadoghq.com/getting_started/tagging/unified_service_tagging.md) enabled | | `marathon_app` | Low | Marathon environment | | `chronos_job` | Low | Mesos environment | | `chronos_job_owner` | Low | Mesos environment | | `nomad_task` | Low | Nomad environment | | `nomad_job` | Low | Nomad environment | | `nomad_group` | Low | Nomad environment | | `git.commit.sha` | Low | [org.opencontainers.image.revision](https://github.com/opencontainers/image-spec/blob/02efb9a75ee11e05937b535cc5f228f9343ab2f5/annotations.md#pre-defined-annotation-keys) used | | `git.repository_url` | Low | [org.opencontainers.image.source](https://github.com/opencontainers/image-spec/blob/02efb9a75ee11e05937b535cc5f228f9343ab2f5/annotations.md#pre-defined-annotation-keys) used | ### Unified service tagging{% #unified-service-tagging %} As a best practice in containerized environments, Datadog recommends using unified service tagging when assigning tags. Unified service tagging ties Datadog telemetry together through the use of three standard tags: `env`, `service`, and `version`. To learn how to configure your environment with unified tagging, see the dedicated [unified service tagging documentation](https://docs.datadoghq.com/getting_started/tagging/unified_service_tagging.md). ## Extract labels as tags{% #extract-labels-as-tags %} Starting with Agent v6.0+, the Agent can collect labels for a given container and use them as tags to attach to all data emitted by this container. {% tab title="Containerized Agent" %} To extract a given container label `` and transform it as a tag key `` within Datadog, add the following environment variable to the Datadog Agent: ```bash DD_CONTAINER_LABELS_AS_TAGS='{"":""}' ``` For example, you could set up: ```bash DD_CONTAINER_LABELS_AS_TAGS='{"com.docker.compose.service":"service_name"}' ``` **Note**: `` is not case-sensitive. For example, if you have labels named `foo` and `FOO`, and you set `DD_CONTAINER_LABELS_AS_TAGS='{"foo": "bar"}'`, both `foo` and `FOO` are mapped to `bar`. **Note**: `DD_CONTAINER_LABELS_AS_TAGS` is equivalent to the old `DD_DOCKER_LABELS_AS_TAGS`, and `DD_CONTAINER_ENV_AS_TAGS` to `DD_DOCKER_ENV_AS_TAGS`. {% /tab %} {% tab title="Agent" %} To extract a given container label `` and transform it as a tag key `` within Datadog, add the following configuration block in the [Agent `datadog.yaml` configuration file](https://docs.datadoghq.com/agent/configuration/agent-configuration-files.md#agent-main-configuration-file): ```yaml container_labels_as_tags: : ``` For example, you could set up: ```yaml container_labels_as_tags: com.docker.compose.service: service_name ``` {% /tab %} ## Extract environment variables as tags{% #extract-environment-variables-as-tags %} Datadog automatically collects common tags from [Docker, Kubernetes, ECS, Swarm, Mesos, Nomad, and Rancher](https://docs.datadoghq.com/agent/docker.md?tab=standard#tagging). To extract even more tags, use the following options: | Environment Variable | Description | | ---------------------------------- | --------------------------------------- | | `DD_CONTAINER_LABELS_AS_TAGS` | Extract container labels | | `DD_CONTAINER_ENV_AS_TAGS` | Extract container environment variables | | `DD_KUBERNETES_POD_LABELS_AS_TAGS` | Extract pod labels | | `DD_CHECKS_TAG_CARDINALITY` | Add tags to check metrics | | `DD_DOGSTATSD_TAG_CARDINALITY` | Add tags to custom metrics | Starting with Agent v7.20+, a containerized Agent can Autodiscover tags from container labels. This process allows the Agent to associate custom tags to all data emitted by a container without modifying the Agent `datadog.yaml` file. Tags should be added using the following format: ```yaml com.datadoghq.ad.tags: '[":", ":"]' ``` With Agent v6.0+, the Agent can collect environment variables for a given container and use them as tags to attach to all data emitted by this container. {% tab title="Containerized Agent" %} To extract a given container environment variable `` and transform it as a tag key `` within Datadog, add the following environment variable to the Datadog Agent: ```bash DD_CONTAINER_ENV_AS_TAGS='{"": ""}' ``` For example, you could set up: ```bash DD_CONTAINER_ENV_AS_TAGS='{"ENVIRONMENT":"env"}' ``` {% /tab %} {% tab title="Agent" %} To extract a given container environment variable `` and transform it as a tag key `` within Datadog, add the following configuration block in the [Agent `datadog.yaml` configuration file](https://docs.datadoghq.com/agent/configuration/agent-configuration-files.md#agent-main-configuration-file): ```yaml container_env_as_tags: : ``` For example, you could set up: ```yaml container_env_as_tags: ENVIRONMENT: env ``` {% /tab %} ## Further Reading{% #further-reading %} - [Getting started with tags](https://docs.datadoghq.com/getting_started/tagging.md) - [Using tags with Datadog](https://docs.datadoghq.com/getting_started/tagging/using_tags.md) - [Limit data collection to a subset of containers only](https://docs.datadoghq.com/agent/guide/autodiscovery-management.md)