Notes/System Design/08 Observability/05 Telemetry Ingestion Pipeline

3.4 Scaling Each Layer

Scaling unit and trigger for every layer of the telemetry ingestion pipeline, from the ingestion gateway through to storage.

Chapter Navigation
On This Page

Appears in: Telemetry Ingestion Pipeline — §3, Deep Dives — this is §3.4.

3.4 Scaling Each Layer

LayerScaling unitScaling triggerNotes
Ingestion gatewayPod replicas (HPA)CPU > 70% OR active connections > 10KStateless; L7 load balancer distributes
Kafka brokersPartition countConsumer lag growing + broker CPU > 80%Increase partitions; re-assign partition leaders
Metric processorConsumer group podsConsumer lag > target (e.g., 60s worth)Pods = partition count for maximum parallelism
Trace assemblerStateful shard podsMemory > 70% OR assembly latency risingResharding is costly; over-provision or use consistent hashing
Log processorConsumer group podsConsumer lagStateless; easy to scale
Storage (Mimir)Ingester podsSeries per ingester > targetCortex/Mimir uses ring-based consistent hashing for ingesters

Local graph

Full graph →

Linked from 7 notes

3 — Prometheus in the Observability Ecosystem

Where Prometheus sits in the CNCF landscape — its pull-based cloud-native origins, its companion projects, and where this book does (and doesn't yet) connect it to the wider stack.

2 — Long-Term Storage

Why single-node Prometheus has no built-in long-term-storage or HA story, and how remote_write receivers like Thanos, Cortex, Mimir, and VictoriaMetrics fill that gap at a horizontally-scaled, multi-tenant layer.

3.7 Data Tiering and Compaction (Mimir/Thanos)

Data tiering and compaction in Mimir/Thanos — the ingester-to-object-store journey, compaction levels, vertical compaction/dedup, compaction storms, and the config knobs that control them.

Q3: Trace Sampling Loses Spans During Incident Peaks — Redesign

Full principal-level solution: the trace pipeline drops spans exactly when incidents spike trace volume — diagnose the failure mode and redesign the tail-sampling pipeline to survive it.

Q6: Compactor Queue Backing Up During a Multi-Tenant Flush

Full principal-level solution: diagnose a compactor backlog causing query latency spikes during a large multi-tenant flush, and mitigate it without pausing ingestion.

Prometheus

A book-shaped table of contents for Prometheus: monitoring foundations through architecture, data model, instrumentation, service discovery, PromQL, alerting, production operation, PCA certification, and MAANG interview prep — cross-linking existing notes instead of duplicating them.

Chapter 5 — Telemetry Ingestion Pipeline

Principal/Staff-level design of a high-throughput telemetry ingestion pipeline — requirements, architecture, deep dives, and trade-offs at 10x scale.