SLOs, SLAs, etc.

These terms get thrown around a lot in the industry.

• SLA - Service Level Agreement. This is like a promise you made with another department, your boss, etc. It’s like saying, “We agree to do better than 99% uptime this quarter, otherwise we get fired.”
• SLO - Service Level Objective. This is the actual goal you set internally, in order to meet the SLA. For example, “We must hit 99.9% uptime.”
• SLI - Service Level Indicator. The actual measured metric. For example, “We made 99.99% uptime this quarter.”