--- title: Agent Environment Variables description: >- Configure Datadog Agent settings using environment variables as an alternative to datadog.yaml, including naming conventions and systemd usage. breadcrumbs: Docs > Agent > Agent Guides > Agent Environment Variables --- > For the complete documentation index, see [llms.txt](https://docs.datadoghq.com/llms.txt). # Agent Environment Variables {% alert level="danger" %} For Agent v5, reference the [Docker Agent GitHub repo](https://github.com/DataDog/docker-dd-agent#environment-variables). {% /alert %} ## Overview{% #overview %} For Agent v6, most of the configuration options in the [Agent's main configuration file](https://docs.datadoghq.com/agent/configuration/agent-configuration-files.md#agent-main-configuration-file) (`datadog.yaml`) can be set through environment variables. See the [example configuration files](https://github.com/DataDog/datadog-agent/tree/main/pkg/config/example) in the Datadog Agent GitHub repo for a fully commented reference of all available `datadog.yaml` settings. ## Recommendations{% #recommendations %} As a best practice, 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 [unified service tagging documentation](https://docs.datadoghq.com/getting_started/tagging/unified_service_tagging.md). ## General use{% #general-use %} In general, use the following rules: - Option names should be uppercase with the `DD_` prefix: `hostname` -> `DD_HOSTNAME` - List values should be separated by spaces (Include rules support regexes, and are defined as a list of comma-separated strings): ```yaml container_include: - "image:cp-kafka" - "image:k8szk" # DD_CONTAINER_INCLUDE="image:cp-kafka image:k8szk" ``` - The nesting of config options with **predefined** keys should be separated with an underscore: ```yaml cluster_agent: cmd_port: 5005 # DD_CLUSTER_AGENT_CMD_PORT=5005 ``` - The nesting of config options with **user-defined** keys must be JSON-formatted: ```yaml container_env_as_tags: ENVVAR_NAME: tag_name # DD_CONTAINER_ENV_AS_TAGS='{"ENVVAR_NAME": "tag_name"}' ``` ### Property definition priority{% #property-definition-priority %} - If a property is defined in both the global configuration file (`datadog.yaml`) and as an environment variable, the environment variable takes precedence. - Specifying a nested option with an environment variable overrides *all* the nested options specified under the config option. The exception to this rule is the `proxy` config option. Reference the [Agent proxy documentation](https://docs.datadoghq.com/agent/configuration/proxy.md#environment-variables) for more details. ### Exceptions{% #exceptions %} - Not all `datadog.yaml` options are available with environment variables. See the [core_schema.yaml](https://github.com/DataDog/datadog-agent/blob/main/pkg/config/schema/yaml/core_schema.yaml) configuration schema in the Datadog Agent GitHub repo. Settings tagged `no-env` in the schema don't support environment variables. For earlier Agent versions, the configuration source moved between locations: | Agent version | Configuration source | | ----------------- | ------------------------------------------------------------------------------------------------------------------------------------------ | | 7.51 through 7.83 | `*_settings.go` files under [pkg/config/setup on the 7.83.x branch](https://github.com/DataDog/datadog-agent/tree/7.83.x/pkg/config/setup) | | 7.50 and earlier | [config.go on the 7.50.x branch](https://github.com/DataDog/datadog-agent/blob/7.50.x/pkg/config/config.go) | - Component-specific environment variables not listed in [core_schema.yaml](https://github.com/DataDog/datadog-agent/blob/main/pkg/config/schema/yaml/core_schema.yaml) may also be supported: | Component | Configuration source | Agent 7.51-7.83 | Agent 7.50 and earlier | | --------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------- | | APM Trace Agent | [apm_config.yaml](https://github.com/DataDog/datadog-agent/blob/main/pkg/config/schema/yaml/apm_config.yaml), [Docker APM Agent Environment Variables](https://docs.datadoghq.com/agent/docker/apm.md#docker-apm-agent-environment-variables) | `apm_settings.go` in [pkg/config/setup on the 7.83.x branch](https://github.com/DataDog/datadog-agent/tree/7.83.x/pkg/config/setup) | `apm.go` in [pkg/config on the 7.50.x branch](https://github.com/DataDog/datadog-agent/tree/7.50.x/pkg/config) | | Live Process Agent | [process_config.yaml](https://github.com/DataDog/datadog-agent/blob/main/pkg/config/schema/yaml/process_config.yaml) | `process_settings.go` in [pkg/config/setup on the 7.83.x branch](https://github.com/DataDog/datadog-agent/tree/7.83.x/pkg/config/setup) | `process.go` in [pkg/config on the 7.50.x branch](https://github.com/DataDog/datadog-agent/tree/7.50.x/pkg/config) | | OTLP Ingest | [core_schema.yaml (otlp_config)](https://github.com/DataDog/datadog-agent/blob/main/pkg/config/schema/yaml/core_schema.yaml) | `otlp_settings.go` in [pkg/config/setup on the 7.83.x branch](https://github.com/DataDog/datadog-agent/tree/7.83.x/pkg/config/setup) | `otlp.go` in [pkg/config on the 7.50.x branch](https://github.com/DataDog/datadog-agent/tree/7.50.x/pkg/config) | | System Probe | [system-probe_schema.yaml](https://github.com/DataDog/datadog-agent/blob/main/pkg/config/schema/yaml/system-probe_schema.yaml) | `system_probe_settings.go` in [pkg/config/setup on the 7.83.x branch](https://github.com/DataDog/datadog-agent/tree/7.83.x/pkg/config/setup) | `system_probe.go` in [pkg/config on the 7.50.x branch](https://github.com/DataDog/datadog-agent/tree/7.50.x/pkg/config) | | Private Action Runner | [private_action_runner.yaml](https://github.com/DataDog/datadog-agent/blob/main/pkg/config/schema/yaml/private_action_runner.yaml) | `privateactionrunner_settings.go` in [pkg/config/setup on the 7.83.x branch](https://github.com/DataDog/datadog-agent/tree/7.83.x/pkg/config/setup) | Not available | | Multi-Region Failover | [multi_region_failover.yaml](https://github.com/DataDog/datadog-agent/blob/main/pkg/config/schema/yaml/multi_region_failover.yaml) | `multi_region_failover_settings.go` in [pkg/config/setup on the 7.83.x branch](https://github.com/DataDog/datadog-agent/tree/7.83.x/pkg/config/setup) | Not available | APM Trace Agent example: ```yaml apm_config: enabled: true env: dev # DD_APM_ENABLED=true # DD_APM_ENV=dev ``` Live Process Agent example: ```yaml process_config: process_collection: enabled: true process_dd_url: https://process.datadoghq.com # DD_PROCESS_AGENT_PROCESS_COLLECTION_ENABLED=true # DD_PROCESS_AGENT_URL=https://process.datadoghq.com ``` ## Using environment variables in systemd units{% #using-environment-variables-in-systemd-units %} In operating systems that uses systemd to manage services, environment variables—global (for example, `/etc/environment`) or session-based (for example, `export VAR=value`)—are not generally made available to services unless configured to do so. See [systemd Exec manual page](https://www.freedesktop.org/software/systemd/man/systemd.exec.html#Environment) for more details. From Datadog Agent 7.45, the Datadog Agent service (`datadog-agent.service` unit) can optionally load environment variables assignments from a file (`/environment`). 1. Create `/etc/datadog-agent/environment` if it does not exist. 1. Define newline-separated environment variable assignments. Example: ``` GODEBUG=x509ignoreCN=0,x509sha1=1 DD_HOSTNAME=myhost.local DD_TAGS=env:dev service:foo ``` Restart the service for changes to take effect ## Further Reading{% #further-reading %} Additional helpful documentation, links, and articles: - [Docker Agent environment variables](https://docs.datadoghq.com/agent/docker.md#environment-variables) - [APM Agent environment variables](https://docs.datadoghq.com/agent/docker/apm.md#docker-apm-agent-environment-variables) - [Container log collection](https://docs.datadoghq.com/logs/log_collection.md#container-log-collection) - [Proxy environment variables](https://docs.datadoghq.com/agent/configuration/proxy.md#environment-variables)