Service level objectives (SLO)

Service Level Objectives (SLOs) are important tools for observability that organizations can use to monitor the performance and availability of their services in a systematic and objective way. SLOs enable you to define clear targets for system performance to help in identifying degraded user experience and platform instability. Also, SLOs can be used to track the performance of a service over time to enable organizations to identify trends and patterns in service performance.

Users can set a target for system performance over a time based on the indicator provided. When the target is not reached, further analysis can be completed to determine the cause of the degraded performance.

Terminology

Service level indicator (SLI): Defines the defined quantitative measure of one characteristic of the level of service that is provided to a customer. Common examples include error rate or response latency of a service.

Service level objective (SLO): Defines the target value for the service level that is measured by a SLI. As an example, the SLO might specify that a particular SLI is 99.9% of the defined time.

Error Budget: The specified target value of an SLO implicitly defined a small budget where the service is allowed to not work fully reliably. This error budget allows the incorporation of planned or unplanned downtime of the service that is unavoidable in practice.

Burn Rate: A unitless value that measures how quickly a service consumes its error budget in relation to the target length of its service level objective (SLO). The goal of burn rate is to detect conditions that might result in an SLO violation before it happens.

To learn more and begin creating SLOs, see the following topics: