Service Level Objective
An SLO is an internal reliability target for a service (e.g., 99.9% availability), measured by SLIs, driving error budgets and development cadence.
Purpose
Quantify reliability targets, balancing speed and stability with error budgets.
Mechanism
SLOs set targets based on SLIs (e.g., request success rate, latency percentiles). E.g., 99.9% of requests < 100ms. Error budget = (1−SLO) × time window. Exhausted budget freezes feature work. SLOs should be looser than SLAs.
Use cases
- Reliability targets
- Error budgets
- Capacity planning