Metrics & observability platform
A telemetry funnel with cardinality budgets, sketch-based aggregation (t-digest, HLL), hot/cold storage tiers and rollups — observability that doesn't bankrupt you.
What this design does
Metrics platforms die two deaths: label-cardinality explosions and storing raw forever. This design guards the front door with a funnel that enforces cardinality budgets, aggregates with mergeable sketches so percentiles survive fan-in, keeps 24 hours hot, and rolls everything older into cheap downsampled tiers.
The patterns it composes
- Telemetry ingestion funnel — one hardened front door: validate, budget, drop
- t-digest / HyperLogLog — mergeable sketches — accurate percentiles and uniques at any scale
- Rollups / downsampling — 1s raw → 1m → 1h tiers; cost falls with age
- Cardinality budgeting — per-team label budgets, enforced at ingest not at the bill
- Load shedding — under pressure, drop DEBUG-tier series first — deliberately
Import it, attach your own numbers, and verify the design against failures — or read the engineering notes.