%s executor '%s' doesn't support pause and resume operations

Error message

%s executor '%s' doesn't support pause and resume operations after its start

What it means

Once a test has started, Scheduler.SetPaused asks each executor to pause via the lib.PausableExecutor interface - and only the externally-controlled executor implements it. If any scenario uses another executor type (constant-vus, ramping-vus, per-vu-iterations, shared-iterations, constant-arrival-rate, ramping-arrival-rate), the loop returns this error naming the executor type and scenario that cannot be paused. Pause/resume after start is an externally-controlled-only feature (used by the cloud/distributed control plane).

Source

Thrown at internal/execution/scheduler.go:588

// IMPORTANT: Currently only the externally controlled executor can be paused
// and resumed multiple times in the middle of the test execution! Even then,
// "pausing" is a bit misleading, since k6 won't pause in the middle of the
// currently executing iterations. It will allow the currently in-progress
// iterations to finish, and it just won't start any new ones nor will it
// increment the value returned by GetCurrentTestRunDuration().
func (e *Scheduler) SetPaused(pause bool) error {
	if !e.state.HasStarted() && e.state.IsPaused() {
		if pause {
			return fmt.Errorf("execution is already paused")
		}
		e.state.Test.Logger.Debug("Starting execution")
		return e.state.Resume()
	}

	for _, exec := range e.executors {
		pausableExecutor, ok := exec.(lib.PausableExecutor)
		if !ok {
			return fmt.Errorf(
				"%s executor '%s' doesn't support pause and resume operations after its start",
				exec.GetConfig().GetType(), exec.GetConfig().GetName(),
			)
		}
		if err := pausableExecutor.SetPaused(pause); err != nil {
			return err
		}
	}
	if pause {
		return e.state.Pause()
	}
	return e.state.Resume()
}

View on GitHub (pinned to 93accf6570)

Solutions

If mid-test pause/resume is a hard requirement, drive the run with an externally-controlled executor scenario
Otherwise remove pause/resume from your tooling - plan the whole load shape declaratively via scenarios (stages, startTime) instead
Note the error names the first non-pausable executor; fixing that scenario alone is not enough, every scenario must be externally-controlled

Example fix

// before: normal scenario + external pause attempt -> error
export const options = { vus: 5, duration: '10m' };
// `k6 pause` fails: constant-vus executor 'default' doesn't support pause and resume

// after: externally-controlled executor can be paused/resumed after start
export const options = {
  scenarios: {
    ext: { executor: 'externally-controlled', vus: 2, maxVUs: 10, duration: '10m' },
  },
};

Defensive patterns

Strategy: validation

Validate before calling

// before wiring pause/resume buttons, verify every scenario is externally-controlled
import Options from './options.json';
const allPausable = Object.values(Options.scenarios ?? {}).every(
  (s) => s.executor === 'externally-controlled'
);
if (!allPausable) {
  throw new Error('pause/resume controls require externally-controlled scenarios only');
}

Prevention

Treat pause/resume as a cloud/externally-controlled feature; do not assume it works for local scenario types
Document which test profiles may be paused so operators do not try it on plain scenarios
Prefer declarative load shaping (stages, startTime) over interactive control for local runs

When it happens

Trigger: `k6 pause` / `k6 resume` or PUT /v1/status {"data":{"attributes":{"paused":true}}} on a running test whose options.scenarios contain any executor other than 'externally-controlled'.

Common situations: Teams wiring generic pause/resume buttons into locally-run or self-hosted k6 via the REST API; porting cloud-driven test control flows to plain local scenarios.

Related errors

AI-assisted analysis of grafana/k6@93accf6570 (2026-08-15). Data as JSON: /api/errors/a811a2eca4e6033b. Report an issue: GitHub.