Resource Semantic Conventions

Status: Mixed

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

Status: Stable

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.”

See Attribute Requirement Levels for details on when attributes should be included.

Attributes with Special Handling

Status: Stable

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:

• service.name

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.name
• telemetry.sdk group

Service

Status:

type: service

Description: A service instance.

Attribute	Type	Description	Examples	Requirement Level	Stability
service.name	string	Logical name of the service. [1]	shoppingcart	Required
service.version	string	The version string of the service API or implementation. The format is not defined by these conventions.	2.0.0; a01dbef8a	Recommended

[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.

Service (Experimental)

Status:

type: service

Description: A service instance.

Attribute	Type	Description	Examples	Requirement Level	Stability
service.instance.id	string	The string ID of the service instance. [1]	627cc493-f310-47de-96bd-71410b7dec09	Recommended
service.namespace	string	A namespace for service.name. [2]	Shop	Recommended

[1]: 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).

Implementations, such as SDKs, are recommended to generate a random Version 1 or Version 4 RFC 4122 UUID, but are free to use an inherent unique ID as the source of this value if stability is desirable. In that case, the ID SHOULD be used as source of a UUID Version 5 and SHOULD use the following UUID as the namespace: 4d63009a-8d0f-11ee-aad7-4c796ed8e320.

UUIDs are typically recommended, as only an opaque value for the purposes of identifying a service instance is needed. Similar to what can be seen in the man page for the /etc/machine-id file, the underlying data, such as pod name and namespace should be treated as confidential, being the user’s choice to expose it or not via another resource attribute.

For applications running behind an application server (like unicorn), we do not recommend using one identifier for all processes participating in the application. Instead, it’s recommended each division (e.g. a worker thread in unicorn) to have its own instance.id.

It’s not recommended for a Collector to set service.instance.id if it can’t unambiguously determine the service instance that is generating that telemetry. For instance, creating an UUID based on pod.name will likely be wrong, as the Collector might not know from which container within that pod the telemetry originated. However, Collectors can set the service.instance.id if they can unambiguously determine the service instance for that telemetry. This is typically the case for scraping receivers, as they know the target address and port.

[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.

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

Status:

type: telemetry.sdk

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

Attribute	Type	Description	Examples	Requirement Level	Stability
telemetry.sdk.language	string	The language of the telemetry SDK.	cpp; dotnet; erlang	Required
telemetry.sdk.name	string	The name of the telemetry SDK as defined above. [1]	opentelemetry	Required
telemetry.sdk.version	string	The version string of the telemetry SDK.	1.2.3	Required

[1]: The OpenTelemetry SDK MUST set the telemetry.sdk.name attribute to opentelemetry. If another SDK, like a fork or a vendor-provided implementation, is used, this SDK MUST set the telemetry.sdk.name attribute 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. All custom identifiers SHOULD be stable across different versions of an implementation.

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.

Value	Description	Stability
cpp	cpp
dotnet	dotnet
erlang	erlang
go	go
java	java
nodejs	nodejs
php	php
python	python
ruby	ruby
rust	rust
swift	swift
webjs	webjs

Telemetry Distribution (Experimental)

Status:

type: telemetry.sdk

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

Attribute	Type	Description	Examples	Requirement Level	Stability
telemetry.distro.name	string	The name of the auto instrumentation agent or distribution, if used. [1]	parts-unlimited-java	Recommended
telemetry.distro.version	string	The version string of the auto instrumentation agent or distribution, if used.	1.2.3	Recommended

[1]: Official auto instrumentation agents and distributions SHOULD set the telemetry.distro.name attribute to a string starting with opentelemetry-, e.g. opentelemetry-java-instrumentation.

Compute Unit

Status: Experimental

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

• Container
• Function as a Service
• Process
• Web engine

Compute Instance

Status: Experimental

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

• Host

Environment

Status: Experimental

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

• Operating System
• Device
• Cloud
• Deployment:
  • Deployment Environment
  • Kubernetes
  • CloudFoundry
• Browser

Version attributes

Status: Stable

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

Status: Experimental

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:

• Alibaba Cloud (alibaba_cloud)
• Amazon Web Services (aws)
• Google Cloud Platform (gcp)
• Microsoft Azure (azure)
• Tencent Cloud (tencent_cloud)
• Heroku dyno