SLIs, SLOs & Error Budgets

Summary

An SLI is a measured indicator (e.g. request latency), an SLO is the target for that indicator (e.g. 99.9% of requests under 200ms), and the error budget is the acceptable amount of failure before the SLO is at risk.

• 1Define an SLI and SLO for a hypothetical service (e.g. API uptime).
• 2Calculate the error budget implied by a 99.9% availability SLO over a month.
• 3Learn why error budgets give teams a data-driven way to balance reliability work against new feature work.