Langfuse Service

Langfuse provides comprehensive observability for AI applications, offering detailed tracing, monitoring, and analytics for your ARK agents and teams. This guide covers setting up and using Langfuse with ARK.

Overview

Langfuse integration with ARK provides:

LLM Call Tracing - Track all model interactions and API calls
Cost Monitoring - Monitor API usage and associated costs
Performance Analytics - Response times, throughput, and latency metrics
Session Management - Group related interactions and conversations
Error Tracking - Identify and debug issues in agent workflows

Installation

Quick Start

Deploy Langfuse as part of your ARK installation:


# From repository root - install Langfuse with headless initialization
make langfuse-install
 
# Show credentials and access instructions
make langfuse-credentials

Headless Initialization

Langfuse is automatically configured with:

Organization: ark
Project: ark
User: ark@ark.com / password123
API Keys: Pre-configured for OpenTelemetry integration

The installation automatically:

Deploys Langfuse to the telemetry namespace
Configures OTEL environment variables for ARK services
Restarts ARK controller with proper telemetry configuration

Accessing Langfuse Dashboard

Local Development Access

After installation, you have two options to access Langfuse:

Option 1: Get credentials only


make langfuse-credentials
# Output:
# Username: ark@ark.com
# Password: password123
# 
# To access the dashboard, run:
#   make langfuse-dashboard

Option 2: Start dashboard directly (recommended)


make langfuse-dashboard
# Output:
# Starting Langfuse dashboard...
# 
# Username: ark@ark.com
# Password: password123
# 
# Dashboard available at: http://localhost:3000
# Press Ctrl+C to stop

The dashboard command automatically:

Finds an available port (starting from 3000)
Shows you the exact URL to visit
Starts port-forwarding to Langfuse
Displays the login credentials

Simply visit the URL shown and login with the credentials displayed.

Gateway API Access

Langfuse is configured with Gateway API HTTPRoute for namespace-based access:


# Access via nip.io DNS pattern
open http://langfuse.telemetry.127.0.0.1.nip.io:8080

Configuration

OTEL Environment Variables

The installation automatically configures these OpenTelemetry environment variables:


# Automatically configured by make langfuse-install
OTEL_EXPORTER_OTLP_ENDPOINT=http://langfuse-web.telemetry.svc.cluster.local:3000/api/public/otel
OTEL_EXPORTER_OTLP_HEADERS=Authorization=Basic <base64-encoded-credentials>

Service Configuration

Langfuse is deployed with these default settings:

Namespace: telemetry
Service Name: langfuse-web
Port: 3000
Public Key: lf_pk_1234567890
Secret Key: lf_sk_1234567890

Automatic OTEL Header Deployment

The installation automatically deploys OTEL configuration to:

ark-system namespace
default namespace

This enables automatic telemetry collection from ARK services.

Using Langfuse Dashboard

Dashboard Overview

Once logged in, the Langfuse dashboard provides:

Traces View

Complete execution traces for ARK controller operations
Model calls and responses
Timing and performance metrics

Sessions View

Grouped interactions and conversations
Session-level analytics

Models View

Model usage statistics
Cost breakdown by model
Performance comparisons

Viewing ARK Traces

After installation, you should immediately see a ‘startup’ trace from the ARK controller. This confirms that telemetry is working correctly.

Traces include:

Controller startup events
Query execution flows
Model interactions
Tool executions

Troubleshooting

Langfuse Service Issues


# Check Langfuse pod status
kubectl get pods -l app=langfuse -n telemetry
 
# View Langfuse logs
kubectl logs -l app=langfuse -n telemetry
 
# Check service connectivity
kubectl exec -it <ark-controller-pod> -- curl http://langfuse-web.telemetry.svc.cluster.local:3000/health

OTEL Configuration Issues


# Check OTEL environment variables
kubectl get secret otel-environment-variables -n ark-system -o yaml
 
# Verify ARK controller has OTEL config
kubectl describe deployment ark-controller-manager -n ark-system | grep -A 10 envFrom
 
# Check telemetry initialization logs
kubectl logs deployment/ark-controller-manager -n ark-system | grep telemetry

Dashboard Access Issues


# Check if Langfuse is ready
kubectl get deployment langfuse-web -n telemetry
 
# Test direct port-forward access
kubectl port-forward service/langfuse-web 5264:3000 -n telemetry
 
# Check Gateway API configuration
kubectl get httproute langfuse-telemetry -n telemetry -o yaml

Uninstalling

To remove Langfuse and clean up OTEL configuration:


# Uninstall Langfuse and clean up OTEL secrets
make langfuse-uninstall

This will:

Remove Langfuse from the telemetry namespace
Delete OTEL environment variable secrets from ark-system namespace
Clean up installation stamps