Observability Study Portal

Quick recall Q&A

1. Why use the OTel Collector instead of direct export?

• Decoupling: Apps don't need backend credentials
• Batching: Reduces network overhead
• Processing: Filter, transform, sample at collector level
• Reliability: Retries and buffering
• Multi-backend: Export to multiple destinations

2. What's the difference between Agent and Gateway deployment modes?

Agent (DaemonSet):

• Runs on every node
• Low latency, local collection
• Processes data close to source

Gateway (Deployment):

• Centralized, scaled horizontally
• Aggregates from multiple agents
• Better for cross-cutting processing

3. Explain tail-based vs head-based sampling

Head-based: Decision at trace start (random percentage)

• Simple, predictable
• May miss important traces

Tail-based: Decision after trace completes

• Can sample based on outcome (errors, latency)
• Requires buffering, more resources

4. How do you handle collector failures?

• Use persistent queues (file-based)
• Deploy as StatefulSet with PVCs
• Configure retry policies
• Use load balancer for gateway mode
• Monitor collector health metrics