SRE

• Service Level Indicators (SLI)
  Metrics over time (latency, throughput of requests per second, or failures per request)
• Service Level Objectives (SLO)
  Targets for the cumulative success of SLIs over a period ("last 30 days" or "this quarter")
• Service Level Agreement (SLA)
  Promise by a service provider to a service customer about availability. Usually less than SLO.