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[Instana] Introduction to LLM Observability - New Architecture Without ODCG

By Hiraoka Daisuke posted 02/04/26 06:53 AM

  

Introduction

Starting with IBM Instana Observability 1.0.312, the LLM Observability architecture has been simplified.

Previously, sending Metrics required a separate service called OTel Data Collector for GenAI (ODCG), but this is no longer necessary.

What Changed:

  • Old: Traces/Logs → Instana, Metrics → ODCG → Instana (separate paths)
  • New: Traces/Logs/Metrics → Instana (unified path)

This article explains the new architecture configuration and the role of each component.


Architecture Changes

Previous Configuration (Using ODCG)

Traces/Logs Flow:

OpenLLMetry → Instana Backend (direct)
or
OpenLLMetry → Instana Agent → Instana Backend

Metrics Flow:

OpenLLMetry → ODCG (separate service) → Instana Backend (direct)
or
OpenLLMetry → ODCG (separate service) → Instana Agent → Instana Backend

New Configuration (ODCG Not Required)

Traces/Logs/Metrics Flow (Unified):

OpenLLMetry → Instana Backend (direct - recommended)
or
OpenLLMetry → Instana Agent → Instana Backend

Key Points of the Change:

  • ODCG as a separate service is no longer needed
  • Traces/Logs/Metrics now use the same path (path unification)
  • OpenLLMetry remains required (instrumentation source)
  • Instana Agent is optional (you can choose direct sending or via Agent)

Role of Each Component

Component Roles

Old Configuration Diagram:

image

New Configuration Diagram:

image

Three Important Facts

1. OpenLLMetry Remains Required

Role:

  • Operates within GenAI applications
  • Automatically detects and instruments LLM calls
  • Captures token count, cost, and latency
  • Generates data in OpenTelemetry format

Status: No Change - Still Required

Important: Without OpenLLMetry, GenAI operation visibility is impossible.

2. ODCG Only Handled Relay Processing

Role:

  • Relay point between OpenLLMetry and Instana
  • Data aggregation and forwarding
  • Price information management (prices.properties)

Status: Deprecated - Removal Recommended

Why It's No Longer Needed:

  • Instana Backend can now process GenAI data directly
  • Price information can be managed in Instana UI
  • Single endpoint receives both traces and metrics
  • Additional relay point is unnecessary

3. Instana Agent Is an Optional Component

Role:

  • Optional data aggregation point
  • Aggregates data from multiple applications in one place
  • Integration with existing Instana monitoring infrastructure

Important: ODCG functionality did not move to the Agent. The Agent was and remains an "optional component."


Essence of the Change

What Changed

Item Old New
Data Path OpenLLMetry → ODCG → Instana OpenLLMetry → Instana (direct or via Agent)
Relay Point ODCG required ODCG not needed
Number of Endpoints 2 (for traces and metrics) 1 (unified)
Price Management ODCG's prices.properties Instana UI
Configuration Complexity Complex (ODCG deployment & config needed) Simple (environment variables only)

What Didn't Change

Item Status Description
OpenLLMetry Still required Continues as instrumentation source
Instrumentation Method No change Automatic LLM call detection
Instrumentation Code No change needed Traceloop code remains the same
Instana Agent Optional (was optional before) Free to choose whether to use
Visualization Features No change Display in Instana UI is the same

Configuration Patterns

Pattern 1: Agentless 

GenAI App
    ↓ [OpenLLMetry instruments] ← Required
OpenLLMetry
    ↓ [Direct sending]
Instana Backend

Characteristics:

  • Simplest approach
  • Instana Agent not required
  • ⚠️ OpenLLMetry is required

Configuration Example:

export TRACELOOP_BASE_URL=export"x-instana-key=exporttrueexportfalseexport"INSTANA_PLUGIN=genai"

Pattern 2: Via Agent

GenAI App
    ↓ [OpenLLMetry instruments] ← Required
OpenLLMetry
    ↓ [Via Agent]
Instana Agent
    ↓
Instana Backend

Characteristics:

  • Effective for aggregating multiple applications
  • Leverages existing Agent infrastructure
  • Enables correlation analysis with infrastructure (Important)
  • ⚠️ OpenLLMetry is required

Benefits:

  • Can correlate infrastructure metrics (CPU, memory, network, etc.) with GenAI metrics
  • Unified understanding of application performance issues and infrastructure problems
  • Easier troubleshooting

Pattern 3: Old Configuration (Deprecated)

GenAI App
    ↓ [OpenLLMetry instruments]
OpenLLMetry
    ↓ [Via ODCG]
ODCG ← Deprecated
    ↓
Instana Backend

Characteristics:

  • Removal recommended
  • Complex configuration
  • High operational cost
  • ODCG redeployment needed when updating prices

Summary

Core Understanding

  1. OpenLLMetry = Instrumentation Source (Required, no change)

    • The only means to automatically instrument GenAI operations
    • Visibility is impossible without this
  2. ODCG = Relay Point (Deprecated, removal recommended)

    • Simply data relay and aggregation processing
    • No longer needed as Instana Backend can process directly
  3. Instana Agent = Optional Aggregation Point (Optional, no change)

    • Was and remains an "optional" component
    • ODCG functionality did not move here
  4. Instana Backend = Final Storage Destination (Required, enhanced functionality)

    • Can now process GenAI data directly
    • Integrated price management functionality

Essence of the Change

"Simplification through removal of relay point," not "change in instrumentation method"


References

Conclusion

Instana's LLM Observability has become simpler and easier to adopt with the removal of ODCG.

Configuration Points:

  • Instrument GenAI operations with OpenLLMetry
  • Send directly to Instana Backend (or via Agent)
  • Complete with environment variable configuration only

I hope this helps those starting LLM monitoring. If you have questions or additional information, feel free to comment!


Tags: #Instana #LLM #GenAI #Observability #OpenTelemetry #OpenLLMetry #IBM


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