How to share custom data along with the script?

[devilankur18]

For example scirpt need to run have 100k users ids, so how to

• add data while invoking script
• How to distribute the data between jobs, so for 4 parallel runs, 25K unique users would go each.

[Juandavi1]

Hi,

you can share the information with a pv that uses for example an azure file share.

[mycargus]

We wanted the same feature, particularly splitting the user IDs across distributed load generators. As far as I know, k6-operator doesn't support that feature right now. We devised a different approach and it works well for us.

Instead of feeding the k6-operator a file with a bunch of username+password combos, we leverage k6's awesome Virtual User __VU env var to keep it simple.

From the k6 docs, __VU is:

"Current VU number. The value is assigned incrementally for each new VU instance. One-based."

So, every virtual user in your load test has a unique ID.

Here's our flow:

1. Pre-seed your application with as many users as you want. If you want 10,000 virtual users throwing load at your application during a load test, then seed 10,000 users in your application. You can use any username format you want as long as the username contains a one-based counter. For example, [email protected], [email protected], ... [email protected], [email protected].
2. Since the load test is likely hitting a public site, the seeded password for each user should be secure and unique. Use a shared password with a one-based counter that corresponds to the username. For example, user1 will have the password S3kr3tpassword1, user2 will have S3kr3tpassword2, etc. This will make sense in a minute.
3. Create a secret in your kubernetes cluster. You must create it in the k6-operator-system namespace (or whatever namespace you applied when deploying k6-operator to your cluster):

kubectl -n k6-operator-system create secret generic tutorial-password --from-literal password-base=S3kr3tpassword

4. Add the secret to the .spec.runner.env[] pod configuration in your-k6-test.yaml like so:

spec:
  runner:
    env:
    - name: USER_PASSWORD_BASE
      valueFrom:
        secretKeyRef:
          name: "tutorial-password"
          key: password-base

5. Now each virtual user can use your new USER_PASSWORD_BASE and the k6 __VU env var to login to your app:

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

export default function () {
  const vu = `${__VU}`;
  const email = `user${vu}@mail.com`;
  const password = `${__ENV.USER_PASSWORD_BASE}${vu}`;

  console.log(`VU: ${vu}  -  email: ${email}  -  password: ${password}`);

  const payload = JSON.stringify({ email: email, password: password });
  const params = { headers: { 'Content-Type': 'application/json' } };
  http.post('http://test.k6.io/login', payload, params);

  // .. continue the user flow

  sleep(1);
}

Hope this helps!

[knechtionscoding]

@mycargus The only thing I'll say, is you need the secret to be created in the same place as the job that is being run. Not specifically the namespace where the k6 operator is installed.

You can run jobs in lots of namespaces besides the k6-operator one.

[yorugac]

@mycargus thanks for sharing your workaround!

This issue might be partially solved with the ongoing work done in https://github.com/grafana/k6/issues/1539 which is an addition of data segmentation API to k6. But the creation and management of secrets is specific for k6-operator use case so we need to evaluate whether some additional support for data segmentation is needed in k6-operator itself.

IOW, I'd consider this issue blocked until at least https://github.com/grafana/k6/pull/2273 is merged.

[testn]

What else can we do for this? Can we add some identifier to identifier the worker node id?

[yorugac]

Hi @testn, thanks for monitoring and commenting! This issue is still valid, AFAIK, and it looks like Data Segmentation in k6 remains valid too. However, as mentioned in this comment, it might make sense to try to use the execution API of k6 and see what it's pros and cons here are.

Can we add some identifier to identifier the worker node id?

I'm not sure what you meant here. The operator already has runner ID, attached as tags to the metrics.

[testn]

Runner id is not enough, we need to know which node is supposed to handle 1st, 2nd, 3rd, etc. part of the data.