Service objectives

An objective #

An objective pairs a target with a window. The target is the level of service you promise; the window is the period over which you are judged.

• Target — 99.9% of requests succeeding.
• Window — 7, 30 or 90 days.
• SLI — the service level actually achieved in the window.
• Budget remaining — how much of the allowed failure is left.
• Burn rate — how fast the budget is being spent.
• Status — on track, approaching the limit, or breached.

How the numbers work #

The service level indicator is the share of requests that succeeded. The error budget is the share of failures you may spend: a 99.9% target gives you 0.1%.

SLI              = 100 - error rate
Error budget     = 100 - target
Budget remaining = how much of the budget is unspent
Burn rate        = budget spent / budget allowed

Status #

• On track — the indicator is meeting the target.
• Approaching — the target is met but little budget remains.
• Breached — the indicator is below the target.

The daily series #

Each objective carries a daily series so you can see the day the target was missed. A single breach day inside a 30-day window is a warning; several is a trend.

Using objectives #

• Put an objective widget on the dashboard you watch daily.
• Alert on budget burn rate rather than on a single error.
• Review an objective's trend before agreeing to a new target.

Reading objectives together #

Objectives are derived from your services' real traffic, so an objective list reflects what your users actually experience. A service with no traffic has no objective to show.