Cloud role name and instance: definition

Every Application Insights row carries cloud_RoleName and cloud_RoleInstance (AppRoleName and AppRoleInstance in a workspace). When two or more services send to the same resource, Microsoft says you’re required to set role names; without them Application Map shows one node, and the services’ requests, failures and percentiles blur together.

The OpenTelemetry distros for .NET, Node.js and Python take the role name from the service.namespace and service.name resource attributes, falling back to service.name alone, and the instance from service.instance.id. Set them through environment variables; OTEL_SERVICE_NAME wins over a name in OTEL_RESOURCE_ATTRIBUTES:

OTEL_SERVICE_NAME=checkout-api
OTEL_RESOURCE_ATTRIBUTES=service.instance.id=checkout-7f9c

With those two lines, the service’s rows arrive with cloud_RoleName checkout-api and cloud_RoleInstance checkout-7f9c.

The Java agent reads APPLICATIONINSIGHTS_ROLE_NAME and APPLICATIONINSIGHTS_ROLE_INSTANCE (or role.name and role.instance in its JSON file), and defaults to the resource name and the machine name. The classic .NET SDK sets telemetry.Context.Cloud.RoleName in a telemetry initializer.

Keep role names stable and few: one per deployable service, not one per version or per pod. The version belongs in application_Version, the host or pod name in the instance.

Where it comes up

Correlation in Application Insights: trace context, operation_Id and Application Map

Guide · How operation_Id and operation_ParentId map to W3C trace context, why Application Map shows one node or none, and how to correlate work across queues.

Telemetry initializers in Application Insights, and their OpenTelemetry equivalents

Guide · What ITelemetryInitializer and ITelemetryProcessor do, how to add custom dimensions and role names, and the OpenTelemetry processors that replace them.

Attach version and build information to Application Insights telemetry

Guide · Set application_Version from your build in the classic SDK, SDK 3.x and OpenTelemetry (service.version), mark deployments, and compare versions in KQL.

Request latency p50, p95 and p99 by cloud role

KQL · One row per cloud role name with its request count and its p50, p95 and p99 duration in milliseconds, slowest p95 first.

Cloud role instances and versions seen per role

KQL · One row per service and application version with its sampling-adjusted request count, the number and names of instances that served it, and when it was first and last seen in the window.

Related terms

operation_Id

The Application Insights column that ties together every row of one distributed operation; in OpenTelemetry and W3C Trace Context terms it is the trace ID.

Telemetry initializer

A hook in the classic Application Insights SDK that runs on every telemetry item before it is sent, used to add or correct properties such as the cloud role name, user ID or a custom dimension.

Dependency

A call an app makes to something outside it, such as an HTTP API, a database, a queue or a cache, recorded in the dependencies table with its target, duration and result.

Where it comes up

Related terms

Sources, checked Oct 21, 2026