Yesterday I mentioned that I’d used the constant-vus executor to recreate the stepped load profile. Well, the thing about learning publicly is that it also means making mistakes publicly!

I was kindly informed by a few of my new colleagues that constant-vus was not the most optimal way to recreate the stepped load profile. Simme wrote up a little function so I wouldn’t have to repeat myself so much, and Pepe Cano and Pawel Suwala (the CTO of k6 himself) both told me nicely that using stages would have been the better solution.

So, let’s chalk that up to a TIL (Today I Learned) and record that snippet here for prosperity (found in the k6 documentation linked above):

import http from 'k6/http';
import { check, sleep } from 'k6';

export let options = {
  stages: [
    { duration: '30s', target: 20 },
    { duration: '1m30s', target: 10 },
    { duration: '20s', target: 0 },
  ],
};

export default function () {
  let res = http.get('https://httpbin.org/');
  check(res, { 'status was 200': (r) => r.status == 200 });
  sleep(1);
}