# SLO/SLI

> A rule or precondition that a service's reliability is stated as a measured indicator with an objective and an error budget over a window.

Record: `architecture:slo-sli`
Kind: constraint
Layer: [Observability](https://banes-lab.com/records/layer/observability.md)
Severity: contextual
Scope: service, reliability, operations
Aliases: Service Level Objective, Service Level Indicator, Objective Reliability Targets
Canonical: https://banes-lab.com/ontology#architecture-slo-sli

Listed in [Architecture principles](https://banes-lab.com/api/records/architecture.md), after [Distributed Tracing](https://banes-lab.com/records/architecture/distributed-tracing.md) and before [Dashboards](https://banes-lab.com/records/architecture/dashboards.md).

## Repair

- Refactored by: Define SLIs and SLOs
- Detected by: no measured indicator behind reliability claims
- Violated by: reliability judged by subjective feel
- Measured by: SLO attainment vs error budget
- Enforced by: reliability review

## Requires

- [Monitoring](https://banes-lab.com/records/architecture/monitoring.md)

## Reinforces

- [Observability](https://banes-lab.com/records/architecture/observability.md)
- [Alerting](https://banes-lab.com/records/architecture/alerting.md)

## Enables

- [Error-Budget Decisions](https://banes-lab.com/records/lexicon/error-budget-decisions.md)

## Conflicts with

- [Vague Reliability Goals](https://banes-lab.com/records/lexicon/vague-reliability-goals.md)

## In tension with

- [Feature Velocity](https://banes-lab.com/records/lexicon/feature-velocity.md)

## Tensions

- [SLO/SLI / Feature Velocity](https://banes-lab.com/records/tension/feature-velocity-slo-sli.md)

## Severity

- [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md)

## Category

- [Observability / Auditability / Traceability](https://banes-lab.com/records/architecture-category/observability-auditability-traceability.md)

## Linked from

- [Observability / Auditability / Traceability](https://banes-lab.com/ontology/principles/architecture-category-observability-auditability-traceability.md)
- [Observability / Auditability / Traceability](https://banes-lab.com/ontology/lexicon/lexicon-category-observability-auditability-traceability.md)
- [Severity levels](https://banes-lab.com/ontology/schema/the-vocabulary-severity.md)
- [The resolutions](https://banes-lab.com/ontology/schema/the-resolutions.md)