Azure/azure-sdk-for-net Azure.Monitor.OpenTelemetry.AspNetCore_1.5.0

on GitHub

1.5.0 (2026-04-30)

Features Added

• Add ability to specify EnableStandardMetrics and EnablePerformanceCounters
  (#56438)

Breaking Changes

• Default Sampler Changed: The default sampling behavior has been changed from
  ApplicationInsightsSampler with 100% sampling (all traces sampled) to
  RateLimitedSampler with 5.0 traces per second. This change significantly
  reduces telemetry volume for high-traffic applications and provides better
  cost optimization out of the box.
  Impact: Applications with more than 5 requests per second will see fewer
  traces exported by default.
  Migration: To maintain the previous behavior (100% sampling), explicitly
  configure the sampler:

// Option 1: Set SamplingRatio and clear TracesPerSecond
builder.Services.AddOpenTelemetry()
    .UseAzureMonitor(options =>
    {
        options.SamplingRatio = 1.0f;
        options.TracesPerSecond = null;
    });
// Option 2: Use environment variables
// OTEL_TRACES_SAMPLER=microsoft.fixed_percentage
// OTEL_TRACES_SAMPLER_ARG=1.0

Bugs Fixed

• Fixed an issue where Azure Container Apps instances were showing VM instance GUIDs
  instead of replica names in the Role Instance field.
  (#54586)