Reliability & SRE Skill

Goal

To treat operations as a software problem and balance improved reliability with feature velocity.

Capabilities

1. Service Level Objectives (SLO)

• SLI: What you measure (e.g., Latency < 100ms).
• SLO: The target (e.g., 99.9% of requests meet SLI).
• Structure: 28-day rolling window. 99.9% = 43m downtime.

2. Error Budgets

• Definition: 1 - SLO. The allowed unreliability.
• Policy: If budget is exhausted -> Freeze feature launches -> Focus on stability.

3. Incident Management

• Postmortems: Blameless analysis of process failure, not human error.
• Severity Levels: SEV1 (Critical/Down) to SEV4 (Minor bug).
• MTTR: Mean Time To Recovery (Focus on fixing fast, not just preventing failure).