Load Testing with k6 in CI/CD
Load testing simulates multiple concurrent users to measure how a system performs under expected and peak load. Integrating load tests into CI/CD catches performance regressions early — before they affect production users. k6 is a modern, developer-friendly load testing tool that integrates well into automated pipelines.
k6 Overview
k6 (Grafana k6) is an open source load testing tool designed for developer workflows. Tests are written in JavaScript, version-controlled alongside application code, and run from the command line or CI. k6 provides detailed performance metrics: response time percentiles (p50, p95, p99), request rate, error rate, and check pass rate.
Load Test Scenarios
- Smoke test: Minimal load (1-2 VUs) — verifies the system works at all under test conditions
- Load test: Expected production load — verifies the system meets performance requirements under normal conditions
- Stress test: Load beyond normal capacity — identifies at what point the system degrades
- Spike test: Sudden load increase — simulates traffic spikes (viral content, marketing campaigns)
- Soak test: Sustained normal load over extended time — identifies memory leaks and resource exhaustion
CI/CD Integration
Run smoke and load tests as part of deployment pipelines — especially to staging environments. Use k6 thresholds to fail the pipeline if performance degrades: http_req_duration: ['p95<500'] fails the test if 95th percentile response time exceeds 500ms. Compare results over time to detect gradual performance degradation.