Ruby

A Ruby service gets eBPF monitoring out of the box with no code change, and deeper OpenTelemetry tracing once you add the Ruby gems to the app. The agent can’t inject a Ruby SDK from outside, because Ruby only loads gems listed in the app’s Gemfile. For the shared opt-in flow, see the Application APM overview.

eBPF monitoring, no code change

eBPF monitoring gives a Ruby service HTTP server traces, RED metrics (request rate, errors, and duration), and the service map from the kernel, with no gem and on any Ruby version. This is the same coverage Go gets, and it works on Linux, Kubernetes, and Docker. On Kubernetes it’s the only trace path for Ruby, since there’s no OpenTelemetry Operator injector for it.

Deep Ruby tracing with the OpenTelemetry gems

For database queries, view rendering, background jobs, and outbound HTTP calls, add the OpenTelemetry Ruby gems to the app’s Gemfile. With them, use_all traces the whole request path.

# Gemfile
gem 'opentelemetry-sdk'
gem 'opentelemetry-instrumentation-all'
gem 'opentelemetry-exporter-otlp'

# config/initializers/opentelemetry.rb
require 'opentelemetry/sdk'
require 'opentelemetry/instrumentation/all'
require 'opentelemetry/exporter/otlp'
OpenTelemetry::SDK.configure { |c| c.use_all }

Set the service name and where to send traces through the app’s environment:

OTEL_SERVICE_NAME=my-rails-app
OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318

The SQL query text on a database span comes from the driver instrumentation (pg, mysql2), not from ActiveRecord. A database with no OpenTelemetry driver, such as SQLite, shows the model operation (User#save) but no SQL. For the full breakdown of what these gems capture, see Ruby manual instrumentation.

Versions

The current OpenTelemetry Ruby gems need Ruby 3.3 or newer. On Ruby 3.0 to 3.2 you have to pin older gem versions, and on Ruby 2.x they won’t install at all. On those versions, use eBPF monitoring, which doesn’t depend on the Ruby version.

Next steps

eBPF observability The kernel-level monitoring that covers Ruby.

Ruby manual instrumentation What the OpenTelemetry Ruby gems capture.

Application APM overview How opt-in tracing works.