What is referred to as the error budget in SLOs?

The error budget in the context of Service Level Objectives (SLOs) is defined as the remaining buffer until a defined target is reached. It quantifies the acceptable level of errors or failures that can occur without violating the service level agreement or objective. Essentially, this budget allows a certain percentage of errors or downtime, which helps teams manage reliability while still permitting flexibility for development and deployment activities.

This concept is crucial because it provides teams with a measurable framework to balance the need for system reliability against the pace of new feature releases or updates. By knowing how much "error" is acceptable, teams can make informed decisions about where to allocate resources, when to prioritize reliability improvements, and when they can afford to take risks in their development practices.

The error budget also helps in fostering a culture of accountability, encouraging teams to monitor their service performance closely and take corrective actions if they are nearing the limits of their budget. Thus, the significance of establishing a clear error budget cannot be overstated; it is essential for maintaining a healthy balance between delivering new features and ensuring consistent service reliability.