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Load testing is a critical aspect of ensuring backend systems can handle real-world traffic. Instead of arbitrary request-per-second (RPS) values, a data-driven approach ensures reliability. Hereās how to perform realistic load testing using k6, along with key insights.
You Should Know:
1. Pull Real Production Traffic Stats
Before testing, analyze actual API usage:
- Daily/hourly request counts ā Convert to RPS.
- Example: If an API gets 8,640 calls/day, thatās 0.1 RPS (
8640 / 86400).
- Design a k6 Test with a Safety Margin
A 1-hour test simulating 3.5 RPS (35x real traffic) ensures scalability.
Example k6 Script:
import http from 'k6/http';
import { sleep } from 'k6';
export let options = {
stages: [
{ duration: '5m', target: 3.5 }, // Ramp-up
{ duration: '50m', target: 3.5 }, // Sustained load
{ duration: '5m', target: 0 }, // Ramp-down
],
};
export default function () {
http.get('https://api.example.com/product-data');
sleep(1);
}
3. Use a Preview Environment Matching Prod
- Same CPU, memory, and pod configuration as production.
- Avoid testing directly on prod to prevent unintended outages.
4. Monitor with Grafana & Loki
Track:
- Latency (p95, p99)
- CPU/Memory usage
- Error rates
Grafana Query Example:
[promql]
sum(rate(container_cpu_usage_seconds_total{namespace=”preview”}[5m])) by (pod)
[/promql]
5. Cache Considerations
- Issue: Repeated IDs may hit cached responses, skewing results.
- Fix: Randomize IDs or disable caching headers:
headers: { 'Cache-Control': 'no-cache' }
What Undercode Say
Load testing isnāt just about extreme stressābaseline tests with real data are often more valuable. Key takeaways:
– Test beyond current traffic (e.g., 3.5 RPS for 0.1 RPS real traffic).
– Monitor infrastructure resilience (CPU, memory, latency).
– Avoid cache skew by randomizing requests or disabling caching.
Linux/Windows Commands for Load Testing:
Stress CPU (Linux) stress --cpu 4 --timeout 60s Monitor Network (Linux) iftop -i eth0 Windows Performance Monitor perfmon /res Generate HTTP traffic (Linux) ab -n 1000 -c 100 http://test.api/endpoint
Expected Output:
A system handling 3.5 RPS with:
- 0 errors
- Low, consistent latency
- Minimal CPU/memory impact
For more on k6, visit: k6.io/docs.
References:
Reported By: Sarahenriques Dev – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ā
