Resource Semantic Conventions

Status: Experimental

This document defines standard attributes for resources. These attributes are typically used in the Resource and are also recommended to be used anywhere else where there is a need to describe a resource in a consistent manner. The majority of these attributes are inherited from OpenCensus Resource standard.

TODOs

  • Add more compute units: AppEngine unit, etc.
  • Add Web Browser.
  • Decide if lower case strings only.
  • Consider to add optional/required for each attribute and combination of attributes (e.g when supplying a k8s resource all k8s may be required).

Document Conventions

Attributes are grouped logically by the type of the concept that they described. Attributes in the same group have a common prefix that ends with a dot. For example all attributes that describe Kubernetes properties start with “k8s.”

Certain attribute groups in this document have a Required column. For these groups if any attribute from the particular group is present in the Resource then all attributes that are marked as Required MUST be also present in the Resource. However it is also valid if the entire attribute group is omitted (i.e. none of the attributes from the particular group are present even though some of them are marked as Required in this document).

Attributes with Special Handling

Given their significance some resource attributes are treated specifically as described below.

Semantic Attributes with Dedicated Environment Variable

These are the attributes which MAY be configurable via a dedicated environment variable as specified in OpenTelemetry Environment Variable Specification:

Semantic Attributes with SDK-provided Default Value

These are the attributes which MUST be provided by the SDK as specified in the Resource SDK specification:

Service

type: service

Description: A service instance.

AttributeTypeDescriptionExamplesRequired
service.namestringLogical name of the service. [1]shoppingcartYes
service.namespacestringA namespace for service.name. [2]ShopNo
service.instance.idstringThe string ID of the service instance. [3]627cc493-f310-47de-96bd-71410b7dec09No
service.versionstringThe version string of the service API or implementation.2.0.0No

[1]: MUST be the same for all instances of horizontally scaled services. If the value was not specified, SDKs MUST fallback to unknown_service: concatenated with process.executable.name, e.g. unknown_service:bash. If process.executable.name is not available, the value MUST be set to unknown_service.

[2]: A string value having a meaning that helps to distinguish a group of services, for example the team name that owns a group of services. service.name is expected to be unique within the same namespace. If service.namespace is not specified in the Resource then service.name is expected to be unique for all services that have no explicit namespace defined (so the empty/unspecified namespace is simply one more valid namespace). Zero-length namespace string is assumed equal to unspecified namespace.

[3]: MUST be unique for each instance of the same service.namespace,service.name pair (in other words service.namespace,service.name,service.instance.id triplet MUST be globally unique). The ID helps to distinguish instances of the same service that exist at the same time (e.g. instances of a horizontally scaled service). It is preferable for the ID to be persistent and stay the same for the lifetime of the service instance, however it is acceptable that the ID is ephemeral and changes during important lifetime events for the service (e.g. service restarts). If the service has no inherent unique ID that can be used as the value of this attribute it is recommended to generate a random Version 1 or Version 4 RFC 4122 UUID (services aiming for reproducible UUIDs may also use Version 5, see RFC 4122 for more recommendations).

Note: service.namespace and service.name are not intended to be concatenated for the purpose of forming a single globally unique name for the service. For example the following 2 sets of attributes actually describe 2 different services (despite the fact that the concatenation would result in the same string):

# Resource attributes that describes a service.
namespace = Company.Shop
service.name = shoppingcart
# Another set of resource attributes that describe a different service.
namespace = Company
service.name = Shop.shoppingcart

Telemetry SDK

type: telemetry.sdk

Description: The telemetry SDK used to capture data recorded by the instrumentation libraries.

The default OpenTelemetry SDK provided by the OpenTelemetry project MUST set telemetry.sdk.name to the value opentelemetry.

If another SDK, like a fork or a vendor-provided implementation, is used, this SDK MUST set the attribute telemetry.sdk.name to the fully-qualified class or module name of this SDK’s main entry point or another suitable identifier depending on the language. The identifier opentelemetry is reserved and MUST NOT be used in this case. The identifier SHOULD be stable across different versions of an implementation.

AttributeTypeDescriptionExamplesRequired
telemetry.sdk.namestringThe name of the telemetry SDK as defined above.opentelemetryNo
telemetry.sdk.languagestringThe language of the telemetry SDK.cppNo
telemetry.sdk.versionstringThe version string of the telemetry SDK.1.2.3No
telemetry.auto.versionstringThe version string of the auto instrumentation agent, if used.1.2.3No

telemetry.sdk.language has the following list of well-known values. If one of them applies, then the respective value MUST be used, otherwise a custom value MAY be used.

ValueDescription
cppcpp
dotnetdotnet
erlangerlang
gogo
javajava
nodejsnodejs
phpphp
pythonpython
rubyruby
webjswebjs
swiftswift

Compute Unit

Attributes defining a compute unit (e.g. Container, Process, Function as a Service):

Compute Instance

Attributes defining a computing instance (e.g. host):

Environment

Attributes defining a running environment (e.g. Operating System, Cloud, Data Center, Deployment Service):

Version attributes

Version attributes, such as service.version, are values of type string. They are the exact version used to identify an artifact. This may be a semantic version, e.g., 1.2.3, git hash, e.g., 8ae73a, or an arbitrary version string, e.g., 0.1.2.20210101, whatever was used when building the artifact.

Cloud-Provider-Specific Attributes

Attributes that are only applicable to resources from a specific cloud provider. Currently, these resources can only be defined for providers listed as a valid cloud.provider in Cloud and below. Provider-specific attributes all reside in the cloud_provider directory. Valid cloud providers are: