# Service Level Objectives (SLO) Definitions ## Overview Service Level Objectives (SLOs) define the expected performance and reliability targets for the Integration Standardization system. These objectives guide incident response, feature development prioritization, and infrastructure investment decisions. --- ## SLO Framework ### Service Level Indicators (SLIs) **SLIs** are measurable aspects of service performance: - Availability (uptime percentage) - Latency (response time) - Error Rate (% of failed requests) - Completeness (% of messages delivered) - Correctness (% of data corruption) ### Service Level Agreements (SLAs) **SLAs** are commitments to customers with penalties for non-compliance. ### Service Level Objectives (SLOs) **SLOs** are internal targets that enable SLA compliance while building reliability. **Relationship:** SLO ⊃ SLA (SLO is stricter than SLA) --- ## Core SLOs ### 1. Availability SLO **Definition:** Percentage of time the system is responding to requests. **Target:** 99.9% uptime **Measurement Period:** Rolling 30-day window **Calculation:** ``` Availability = (Total Seconds - Downtime Seconds) / Total Seconds Expected: 99.9% = max 43.2 minutes downtime per month ``` **Error Budget:** 43.2 minutes per month **Tracking:** - Metric: `up{job="integration-standardized"}` - Query: `avg_over_time(up[30d])` - Alert: Availability < 99.8% for 10 minutes **Failure Modes:** - Service completely down - All replicas crashed - Database unreachable - Network partition ### 2. Latency SLO **Definition:** Response time for user requests. **Targets:** | Percentile | Target | Trigger | |-----------|--------|---------| | P50 | 500ms | 750ms | | P95 | 2s | 3s | | P99 | 5s | 7.5s | **Measurement Period:** Continuous (rolling 5-minute windows) **Calculation:** ``` P50 Latency = 50th percentile response time P95 Latency = 95th percentile response time P99 Latency = 99th percentile response time ``` **Error Budget:** - P99 > 7.5s: -10 points per hour - P99 > 5s for 30 minutes: Incident declaration **Tracking:** - Metric: `http_request_duration_seconds_bucket` - Query: `histogram_quantile(0.99, rate(http_request_duration_seconds_bucket[5m]))` - Alert: P99 > 7.5s for 10 minutes **Failure Modes:** - Database query slowdown - Connection pool exhaustion - Coordination protocol delays - Network latency ### 3. Error Rate SLO **Definition:** Percentage of requests that return errors (5xx status codes). **Target:** < 0.1% error rate **Critical Threshold:** > 1% (triggers auto-rollback) **Measurement Period:** Continuous (rolling 5-minute windows) **Calculation:** ``` Error Rate = (5xx responses) / (Total responses) Expected: < 0.1% = max 5 errors per 10,000 requests ``` **Error Budget:** 0.1% per 30-day period **Tracking:** - Metric: `http_requests_total{status=~"5.."}` - Query: `sum(rate(http_requests_total{status=~"5.."}[5m])) / sum(rate(http_requests_total[5m]))` - Alert: Error rate > 0.1% for 10 minutes **Failure Modes:** - Code bugs/exceptions - Database constraint violations - Integration point failures - Resource exhaustion --- ## Integration Point SLOs ### Database Service SLO **Availability:** 99.95% **Latency:** - Read Query P95: < 100ms - Write Query P95: < 200ms - Transaction P95: < 500ms **Error Rate:** < 0.05% **Metrics:** ``` db_queries_total (labeled by operation type) db_query_duration_seconds_bucket db_transaction_duration_seconds_bucket pg_stat_activity_count ``` **Critical Conditions:** - Connection pool > 90% - Replication lag > 30s - Query failure rate > 1% - Disk space < 10% ### Coordination Protocol SLO **Availability:** 99.9% **Message Delivery Success Rate:** > 99.9% **Latency:** - Message delivery P95: < 100ms - Acknowledgment P95: < 50ms **Queue Depth:** < 500 messages **Metrics:** ``` coordination_messages_total coordination_messages_delivered_total coordination_protocol_latency_seconds_bucket redis_queue_size redis_connected_clients ``` **Critical Conditions:** - Redis down - Queue depth > 1000 - Message delivery < 99% - Latency > 500ms ### Artifact Storage SLO **Availability:** 99.9% **Latency:** - Upload P95: < 2s - Download P95: < 1s - List P95: < 500ms **Error Rate:** < 0.1% **Metrics:** ``` artifact_storage_operations_total artifact_storage_errors_total artifact_storage_latency_seconds_bucket artifact_storage_backend_available ``` **Critical Conditions:** - Backend unavailable - Error rate > 1% - Latency > 2x baseline - Storage capacity > 80% ### Metrics Collection SLO **Delivery Rate:** > 99% **Latency:** < 1s **Cardinality Explosion:** < 50k unique metric series **Metrics:** ``` metrics_collection_total metrics_collection_errors_total metrics_collection_latency_seconds_bucket ``` **Critical Conditions:** - Collection service down - Delivery < 95% - Latency > 5s - Series count > 100k --- ## Non-Functional SLOs ### Security SLO **Definition:** Vulnerability detection and remediation. **Targets:** - Zero critical vulnerabilities in production - Security validation latency < 100ms - False positive rate < 0.1% **Tracking:** - Vulnerability scans: Daily - Patch application: Within 48 hours of release - Penetration testing: Quarterly ### Data Integrity SLO **Definition:** Data correctness and consistency. **Targets:** - Zero data corruption incidents - Data consistency validation success > 99.99% - Recovery Time Objective (RTO): < 1 hour **Metrics:** ``` data_consistency_violations_total data_corruption_incidents_total backup_creation_success_rate ``` ### Skill Deployment SLO **Definition:** Integration skill availability and execution. **Targets:** - Skill availability: > 99% - Execution success rate: > 99% - Average execution time: < 5s **Metrics:** ``` skill_deployment_status skill_executions_total skill_executions_failed_total skill_execution_duration_seconds_bucket ``` --- ## Error Budget Management ### Budget Calculation ``` Total Budget = 100% - SLO Target Example: 99.9% SLO = 0.1% budget per month Monthly Budget: 0.1% × 43,200 seconds = 43.2 seconds Hourly Budget: 0.1% × 3,600 seconds = 3.6 seconds ``` ### Budget Tracking ``` Budget Remaining = Total Budget - Consumed Budget Consumed by: - Downtime (full availability loss) - Error rate exceeding SLO - Latency exceeding SLO (weighted) ``` ### Budget Decision Rules **Sufficient Budget (>25%):** - Enable risky deployments - Run chaos engineering experiments - Perform infrastructure maintenance - A/B test new features **Medium Budget (10-25%):** - Careful deployments only - No chaos engineering - Limit infrastructure changes - Conservative feature rollouts **Low Budget (<10%):** - Freeze all non-emergency changes - Emergency incident focus only - Enhanced monitoring - Prepare for manual intervention **Exhausted Budget:** - All non-critical work stopped - Full incident response protocols - Executive escalation - Customer communication --- ## SLO Review and Adjustment ### Quarterly Review **Schedule:** Last week of each quarter **Participants:** Engineering, DevOps, Product, Leadership **Assessment:** - Actual performance vs. SLO target - Error budget consumption - Trend analysis - Customer impact - Infrastructure capacity ### Review Questions 1. Are we meeting the SLO target? 2. Is the error budget appropriate? 3. Are alerts firing too frequently? 4. Are we over-provisioned or under-provisioned? 5. Should we adjust the SLO? ### Adjustment Criteria **Increase SLO Target (more stringent) if:** - Consistently exceeding by >5% - Customer feedback positive - Infrastructure capacity available - Business requirements demand it **Decrease SLO Target (more lenient) if:** - Consistently missing by >5% - Disproportionate infrastructure cost - Business requirements change - Customer satisfaction sufficient --- ## Monitoring and Alerting ### SLO Metrics Dashboard Location: `monitoring/dashboards/integration-overview.json` **Key Panels:** - Availability trend (30-day rolling) - Error rate distribution - Latency percentiles (P50, P95, P99) - Error budget consumption - Integration point health ### Alert Rules **SLO Violation Alerts:** ```yaml Alert: AvailabilitySLOViolation Condition: availability < 99.8% Duration: 10 minutes Severity: Warning Alert: ErrorRateSLOViolation Condition: error_rate > 0.1% Duration: 10 minutes Severity: High Alert: LatencySLOViolation Condition: p99_latency > 7.5s Duration: 10 minutes Severity: High ``` **Error Budget Alerts:** ```yaml Alert: ErrorBudgetLow Condition: consumed_budget > 75% Duration: 1 minute Severity: Warning Alert: ErrorBudgetCritical Condition: consumed_budget > 90% Duration: 1 minute Severity: Critical ``` ### Runbooks **For each SLO violation:** - `docs/INCIDENT_RESPONSE.md` - General procedures - `docs/ROLLBACK_RUNBOOK.md` - Rollback procedures - Integration-specific runbooks (database, coordination, etc.) --- ## SLO Success Criteria ### During Rollout Phases **Phase 1: Canary (10%)** - Maintain SLO targets - Error rate < 0.1% - Latency increase < 5% - Go/No-Go decision at 48 hours **Phase 2: Staged (50%)** - Maintain SLO targets - Error rate < 0.1% - Latency increase < 8% - Go/No-Go decision at 72 hours **Phase 3: Full (100%)** - Maintain SLO targets - Error rate < 0.1% - Latency increase < 10% - Stable for 7 days ### Post-Rollout SLOs **Weeks 1-4:** - 99.9% availability - < 0.1% error rate - P99 latency < 7.5s - No critical incidents **Months 2-3:** - 99.95% availability - < 0.05% error rate - P99 latency < 5s - < 1 SEV2 incident per month **Month 4+:** - 99.95%+ availability - < 0.05% error rate - P99 latency < 5s (normalized) - Capacity planning for growth --- ## Example: SLO Calculation ### Scenario: Monday Error Rate ``` Requests at 10:00: 100,000 Successful: 99,900 Errors: 100 Error Rate: 100/100,000 = 0.1% SLO Target: < 0.1% Status: AT THRESHOLD - Alert triggered Consumed Error Budget: 0.1% for 1 minute = 0.1% / (60 min × 24 hours × 30 days) × 1 min = 0.1% / 43,200 min × 1 min = 0.00000231% per minute = 100 × 0.00000231% = 0.000231% consumed ``` ### Scenario: Monthly Budget Tracking ``` Month: November (2,592,000 seconds) Budget: 0.1% = 2,592 seconds (43.2 minutes) Events: Nov 5: 15-minute outage = 900 seconds consumed (budget: 1,692s remaining) Nov 12: Error rate spike = 10 minutes × 0.1% = 600 seconds consumed (budget: 1,092s remaining) Nov 25: Maintenance window = 30-minute downtime × 100% = 1,800 seconds (EXCEEDS budget) Result: SLO VIOLATED on Nov 25 Impact: Error budget exhausted, all non-critical deployments frozen ``` --- ## References - [Google SRE Book - SLOs](https://sre.google/books/) - Rollout Plan: `docs/ROLLOUT_PLAN.md` - Incident Response: `docs/INCIDENT_RESPONSE.md` - Monitoring Dashboards: `monitoring/dashboards/` - Alert Rules: `monitoring/alerts/` --- **Last Updated:** 2025-11-16 **Version:** 1.0 **Status:** Active **Next Review:** 2026-02-16 (Quarterly)