Tell me about SLI, SLO, and SLA.

SLI (Service Level Indicator) — is a metric that measures a specific aspect of service quality, such as response time, success request percentage, or availability.

SLO (Service Level Objective) — is a target value for the SLI, representing an acceptable level of service quality. For example, 99.9% of responses should be under 200 ms.

SLA (Service Level Agreement) — is a contract between the provider and the client, specifying the SLOs and the consequences of their violation (penalties, compensations).

Example:

• SLI: percentage of successful HTTP requests.
• SLO: 99.95% successful requests per month.
• SLA: if the SLO is not met, the provider compensates the client part of the service cost.

These concepts help manage reliability and quality of services by setting measurable goals and responsibilities.