Observability Engineering

A book-shaped table of contents for observability engineering: foundations through architecture, metrics, logging, tracing, profiling, OpenTelemetry, instrumentation, Kubernetes/cloud, data platforms, visualization, alerting, SRE integration, cost, security, platform engineering, AI-driven operations, and MAANG interview preparation — cross-linking existing prometheus/grafana-cloud/kubernetes/sre/platform-engineering notes instead of duplicating them.

2 — Metric Types

Distinguishes counter, gauge, histogram, and summary semantics and the aggregation rules each type permits or forbids.

4 — Cardinality Management

Covers estimating and bounding active series count before a label change ships, and the incident patterns an unbounded label causes.

6 — Recording Rules

Covers pre-computing expensive PromQL expressions into new series to keep dashboard and alert queries fast at scale.

What is Cortex (cortexproject)

CNCF Incubating, horizontally-scalable multi-tenant long-term storage for Prometheus — the project Grafana Mimir forked from in 2022, still maintained as the vendor-neutral, community-governed alternative once Grafana Labs redirected engineering effort to Mimir.