---

name: slo-implementation description: "定义和实施服务级别指标（SLI）、服务级别目标（SLO）和错误预算的框架。" risk: unknown source: community date_added: "2026-02-27"

SLO 实施

定义和实施服务级别指标（SLI）、服务级别目标（SLO）和错误预算的框架。

不要在以下情况使用此技能

• 任务与 SLO 实施无关时
• 你需要此范围之外的不同领域或工具时

说明

• 明确目标、约束和所需输入。
• 应用相关最佳实践并验证结果。
• 提供可操作的步骤和验证。
• 如果需要详细示例，请打开 resources/implementation-playbook.md。

目的

使用 SLI、SLO 和错误预算实施可衡量的可靠性目标，以平衡可靠性与创新速度。

何时使用此技能

• 定义服务可靠性目标
• 衡量用户感知的可靠性
• 实施错误预算
• 创建基于 SLO 的告警
• 跟踪可靠性目标

SLI/SLO/SLA 层级

SLA (Service Level Agreement)
  ↓ Contract with customers
SLO (Service Level Objective)
  ↓ Internal reliability target
SLI (Service Level Indicator)
  ↓ Actual measurement

定义 SLI

常见 SLI 类型

1. 可用性 SLI

# Successful requests / Total requests
sum(rate(http_requests_total{status!~"5.."}[28d]))
/
sum(rate(http_requests_total[28d]))

2. 延迟 SLI

# Requests below latency threshold / Total requests
sum(rate(http_request_duration_seconds_bucket{le="0.5"}[28d]))
/
sum(rate(http_request_duration_seconds_count[28d]))

3. 持久性 SLI

# Successful writes / Total writes
sum(storage_writes_successful_total)
/
sum(storage_writes_total)

参考： 见 references/slo-definitions.md

设置 SLO 目标

可用性 SLO 示例

| SLO % | 每月停机时间 | 每年停机时间 | |-------|-------------|-------------| | 99% | 7.2 小时 | 3.65 天 | | 99.9% | 43.2 分钟 | 8.76 小时 | | 99.95%| 21.6 分钟 | 4.38 小时 | | 99.99%| 4.32 分钟 | 52.56 分钟 |

选择合适的 SLO

考虑因素：

• 用户期望
• 业务需求
• 当前性能
• 可靠性成本
• 竞争对手基准

SLO 示例：

slos:
  - name: api_availability
    target: 99.9
    window: 28d
    sli: |
      sum(rate(http_requests_total{status!~"5.."}[28d]))
      /
      sum(rate(http_requests_total[28d]))

  - name: api_latency_p95
    target: 99
    window: 28d
    sli: |
      sum(rate(http_request_duration_seconds_bucket{le="0.5"}[28d]))
      /
      sum(rate(http_request_duration_seconds_count[28d]))

错误预算计算

错误预算公式

Error Budget = 1 - SLO Target

示例：

• SLO：99.9% 可用性
• 错误预算：0.1% = 每月 43.2 分钟
• 当前错误：0.05% = 每月 21.6 分钟
• 剩余预算：50%

错误预算策略

error_budget_policy:
  - remaining_budget: 100%
    action: Normal development velocity
  - remaining_budget: 50%
    action: Consider postponing risky changes
  - remaining_budget: 10%
    action: Freeze non-critical changes
  - remaining_budget: 0%
    action: Feature freeze, focus on reliability

参考： 见 references/error-budget.md

SLO 实施

Prometheus 记录规则

# SLI Recording Rules
groups:
  - name: sli_rules
    interval: 30s
    rules:
      # Availability SLI
      - record: sli:http_availability:ratio
        expr: |
          sum(rate(http_requests_total{status!~"5.."}[28d]))
          /
          sum(rate(http_requests_total[28d]))

      # Latency SLI (requests < 500ms)
      - record: sli:http_latency:ratio
        expr: |
          sum(rate(http_request_duration_seconds_bucket{le="0.5"}[28d]))
          /
          sum(rate(http_request_duration_seconds_count[28d]))

  - name: slo_rules
    interval: 5m
    rules:
      # SLO compliance (1 = meeting SLO, 0 = violating)
      - record: slo:http_availability:compliance
        expr: sli:http_availability:ratio >= bool 0.999

      - record: slo:http_latency:compliance
        expr: sli:http_latency:ratio >= bool 0.99

      # Error budget remaining (percentage)
      - record: slo:http_availability:error_budget_remaining
        expr: |
          (sli:http_availability:ratio - 0.999) / (1 - 0.999) * 100

      # Error budget burn rate
      - record: slo:http_availability:burn_rate_5m
        expr: |
          (1 - (
            sum(rate(http_requests_total{status!~"5.."}[5m]))
            /
            sum(rate(http_requests_total[5m]))
          )) / (1 - 0.999)

SLO 告警规则

groups:
  - name: slo_alerts
    interval: 1m
    rules:
      # Fast burn: 14.4x rate, 1 hour window
      # Consumes 2% error budget in 1 hour
      - alert: SLOErrorBudgetBurnFast
        expr: |
          ```