Http_req_failed high on output.json but succed on console output

Grafana k6
1

Hi Team,

I just run loadtest k6 using this script

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


// Accept these status codes as successful
// http.setResponseCallback(
//   http.expectedStatuses(200, 201, 202, 204, 302);
// );

// export let options = {
//   vus: 5, // Number of virtual users
//   duration: '10s', // Test duration
// };

// Load test configuration
export const options = {
    stages: [
        { duration: '10s', target: 10 },
        { duration: '10s', target: 20 },
        { duration: '30s', target: 60 },
        { duration: '90s', target: 20 },
        { duration: '10s', target: 10 },
        { duration: '30s', target: 0 },
    ],
    // Explicit failure thresholds (optional)
    thresholds: {
      http_req_failed: ['rate<0.05'], // Allow <5% failures
      http_req_duration: ['p(95)<1500']
    }
  };

export default function () {
  let res = http.get('https://test.k6.io'); // Replace with your API URL
  
  // ✅ Check if response status is 200
  check(res, {
    'Response status is 200': (r) => r.status === 200,
  });

  

  sleep(1); // Simulate real user wait time
}

The result on console like this below
http_req_failed…: 0.00% 0 out of 3732

    execution: local
        script: ./script-dasar-copy.js
        output: -

     scenarios: (100.00%) 1 scenario, 60 max VUs, 3m30s max duration (incl. graceful stop):
              * default: Up to 60 looping VUs for 3m0s over 6 stages (gracefulRampDown: 30s, gracefulStop: 30s)



  █ THRESHOLDS 

    http_req_duration
    ✓ 'p(95)<1500' p(95)=1.07s

    http_req_failed
    ✓ 'rate<0.05' rate=0.00%


  █ TOTAL RESULTS 

    checks_total.......................: 3732    20.698302/s
    checks_succeeded...................: 100.00% 3732 out of 3732
    checks_failed......................: 0.00%   0 out of 3732

    ✓ Response status is 200

    HTTP
    http_req_duration.......................................................: avg=409.49ms min=249.09ms med=278.85ms max=4.91s p(90)=713.24ms p(95)=1.07s
      { expected_response:true }............................................: avg=409.49ms min=249.09ms med=278.85ms max=4.91s p(90)=713.24ms p(95)=1.07s
    http_req_failed.........................................................: 0.00%  0 out of 3732
    http_reqs...............................................................: 3732   20.698302/s

    EXECUTION
    iteration_duration......................................................: avg=1.44s    min=1.24s    med=1.28s    max=8.5s  p(90)=1.8s     p(95)=2.21s
    iterations..............................................................: 3732   20.698302/s
    vus.....................................................................: 1      min=1         max=60
    vus_max.................................................................: 60     min=60        max=60

    NETWORK
    data_received...........................................................: 43 MB  240 kB/s
    data_sent...............................................................: 400 kB 2.2 kB/s

But on output.json file we got http_req_failed 3732

"root_group": {
        "name": "",
        "path": "",
        "id": "d41d8cd98f00b204e9800998ecf8427e",
        "groups": {},
        "checks": {
                "Response status is 200": {
                    "id": "6231ab582661f5cb4ca95f62ebf36012",
                    "passes": 3732,
                    "fails": 0,
                    "name": "Response status is 200",
                    "path": "::Response status is 200"
                }
            }
    },
    "metrics": {
        "http_req_failed": {
            "passes": 0,
            "fails": 3732,
            "thresholds": {
                "rate<0.05": false
            },
            "value": 0
        },

Can anyone explain why this result ? how to fix it ?

Regards,
Harun