OpenTelemetry Core Concepts: Attributes and Labels

Key:value pairs can be used to affix metadata to spans, events, metrics, and distributed contexts in order to query, filter, and further analyze trace data. Depending on the resource (span, event, or metric), the OpenTelemetry documentation may refer to these key:values as attributes or labels.

Metadata reference	Resource
Attribute	Spans, events
Label	Metrics

Attributes and labels should apply to the entirety of the resource they are describing.

Let’s take a closer look at the Resource Conventions document for definitions of standard attributes for OpenTelemtry’s data resources.

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).

Service

type: service

Description: A service instance.

Attribute	Description	Example	Required?
service.name	Logical name of the service. MUST be the same for all instances of horizontally scaled services.	`shoppingcart`	Yes
service.namespace	A namespace for `service.name`. 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. The field is optional. 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.	`Shop`	No
service.instance.id	The string ID of the service instance. MUST be unique for each instance of the same `service.namespace,service.name` pair (in other words `service.namespace,service.name,service.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).	`627cc493-f310-47de-96bd-71410b7dec09`	Yes
service.version	The version string of the service API or implementation as defined in Version Attributes.	`semver:2.0.0`	No

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). {: .callout}

# Resource attributes that describe a service.
namespace = Company.Shop
service.name = shoppingcart

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

Library

type: library

Description: Telemetry library information.

Attribute	Description	Example	Required?
library.name	The name of the telemetry library.	`opentelemetry`	No
library.language	The language of telemetry library and of the code instrumented with it. The following spelling SHOULD be used for language strings: "cpp", "dotnet", "erlang", "go", "java", "nodejs", "php", "python", "ruby", "webjs"	`java`	No
library.version	The version string of the library as defined in Version Attributes.	`semver:1.2.3`	No

Compute Unit

Attributes defining a compute unit (e.g. Container, Process, Lambda Function).

Container

type: container

Description: A container instance.

Attribute	Description	Example
container.name	Container name.	`opentelemetry-autoconf`
container.image.name	Name of the image the container was built on.	`gcr.io/opentelemetry/operator`
container.image.tag	Container image tag.	`0.1`

Deployment Service

Attributes defining a deployment service (e.g. Kubernetes).

Kubernetes

type: k8s

Description: A Kubernetes resource.

Attribute	Description	Example
k8s.cluster.name	The name of the cluster that the pod is running in.	`opentelemetry-cluster`
k8s.namespace.name	The name of the namespace that the pod is running in.	`default`
k8s.pod.name	The name of the pod.	`opentelemetry-pod-autoconf`
k8s.deployment.name	The name of the deployment.	`opentelemetry`

Compute Instance

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

Host

type: host

Description: A host is defined as a general computing instance.

Attribute	Description	Example
host.hostname	Hostname of the host. It contains what the `hostname` command returns on the host machine.	`opentelemetry-test`
host.id	Unique host id. For Cloud this must be the instance_id assigned by the cloud provider	`opentelemetry-test`
host.name	Name of the host. It may contain what `hostname` returns on Unix systems, the fully qualified, or a name specified by the user.	`opentelemetry-test`
host.type	Type of host. For Cloud this must be the machine type.	`n1-standard-1`
host.image.name	Name of the VM image or OS install the host was instantiated from.	`infra-ami-eks-worker-node-7d4ec78312`, `CentOS-8-x86_64-1905`
host.image.id	VM image id. For Cloud, this value is from the provider.	`ami-07b06b442921831e5`
host.image.version	The version string of the VM image as defined in Version Attributes.	`0.1`

Environment

Attributes defining a running environment (e.g. Cloud, Data Center).

Cloud

type: cloud

Description: A cloud infrastructure (e.g. GCP, Azure, AWS).

Attribute	Description	Example
cloud.provider	Name of the cloud provider. Example values are aws, azure, gcp.	`gcp`
cloud.account.id	The cloud account id used to identify different entities.	`opentelemetry`
cloud.region	A specific geographical location where different entities can run	`us-central1`
cloud.zone	Zones are a sub set of the region connected through low-latency links. In aws it is called availability-zone.	`us-central1-a`

Version Attributes

Version attributes such as service.version and library.version are values of type string, with naming schemas hinting at the type of a version, such as the following:

semver:1.2.3 (a semantic version)
git:8ae73a (a git sha hash)
0.0.4.2.20190921 (a untyped version)

The type and version value MUST be separated by a colon character :.