There are several dimensions available to scope an entire Datadog APM application. These include aggregate statistics (such as requests/second, latency, error rate, Apdex score) and visible traces. These dimensions are set up through primary tags that allow you to get an even finer view of your application’s behavior. Use cases for primary tags include environment, availability zone, datacenter, etc.
Primary tags must follow a different set of rules from those of conventional Datadog tags.
The default and mandatory primary tag is the environment your traces are collected from. Its tag key is
env, and its default value for un-tagged data is
Datadog recommends having the tracer set
env. It also allows for greater flexibility because the definition of
env lives within the actual runtime of the service.
DD_ENV is exposed to your service’s process, the tracer will use it automatically. See Unified Service Tagging to learn about setting
DD_ENV and other standard service environment variables.
You may also manually set
env as a global tag for the tracer in code. See assigning tags in APM for more information.
env tag can be set in your Agent configuration.
env is already present in trace data then it will override any
env set in the Agent.
Top-level Agent configuration:
env: <ENVIRONMENT> ...
Containerized environments: The Agent also supports configuration of the top-level
env through the environment variable
Agent host tag:
tags: env: <ENVIRONMENT> ...
Containerized environments: The Agent also supports configuration of top-level
tags through the environment variable
Environments appear at the top of APM pages. Use the
env dropdown to scope the data displayed on the current page.
If you added a host tag other than
env:<ENVIRONMENT> to your traces, it can be set as a primary tag along with the environment tag. Go to the APM Settings page to define, change, or remove your primary tags.
If you change a previously set primary tag, be aware of the following:
Primary tags appear at the top of APM pages. Use these selectors to slice the data displayed on the current page. To view all data independent of a primary tag, choose
<TAG_NAME>:* from the dropdown.
Additional helpful documentation, links, and articles: