slimtoolkit/slim · error

start monitor timeout

Error message

start monitor timeout

What it means

Pod inspector variant of the start-monitor timeout: sensorCommandStart (called by RunPod in pkg/app/master/inspectors/pod/pod_inspector.go) waits for the sensor monitor to start in the Kubernetes pod and, after exhausting its event waits, returns this ad-hoc error instead of a sentinel. The sensor never confirmed a successful monitor start for the pod.

Source

Thrown at pkg/app/master/inspectors/pod/pod_inspector.go:671

		}

		if evt.Name == event.Error {
			return fmt.Errorf("start monitor error: %v", evt.Data)
		}

		if evt.Name != event.StartMonitorDone {
			i.xc.Out.Info("event.startmonitor.done",
				ovars{
					"status": "received.unexpected",
					"data":   fmt.Sprintf("%+v", evt),
				})

			//TODO: dump temp container logs
			return event.ErrUnexpectedEvent
		}
	}

	return errors.New("start monitor timeout")
}

func (i *Inspector) sensorCommandStop() error {
	resp, err := i.sensorIPCClient.SendCommand(&command.StopMonitor{})
	if err != nil {
		return err
	}
	i.logger.Debugf("'stop' monitor response => '%v'", resp)

	i.logger.Info("waiting for the pod to finish its work...")

	evt, err := i.sensorIPCClient.GetEvent()
	if err != nil {
		return err
	}
	i.logger.Debugf("sensor event => '%v'", evt)
	return nil
}

View on GitHub (pinned to 81940d17fa)

Solutions

1. Check the sensor pod/container logs (kubectl logs) to see why the sensor did not start
2. Ensure cluster network policies allow traffic on the sensor IPC ports between components
3. Retry the inspection; if persistent, verify the sensor image matches the cluster architecture and runs without errors

// Go
if err := RunPod(ctx); err != nil && strings.Contains(err.Error(), "start monitor timeout") {
	// check sensor logs, verify network policies, retry
}

When it happens

Trigger: Running pod inspection when the sensor's start command/IPC never yields a confirming event — sensor container crash, network policy blocking the IPC channel, or the monitor event never arriving before the loop ends.

Common situations: Kubernetes NetworkPolicies blocking sensor traffic; sensor image not schedulable or crashing in the target cluster; slow pod startup exceeding the wait window; RBAC preventing sensor sidecar communication.

Understand the failure class

• Timeouts: ETIMEDOUT, deadlines, and hung requests — what actually expires when a request times out.

Related errors

• Pod terminated
• Pod not running
• start monitor timeout
• unexpected - more than one target pod found
• no pods

AI-assisted analysis of slimtoolkit/slim@81940d17fa (2026-08-31). Data as JSON: /api/errors/9f1d270e887d9fe6. Report an issue: GitHub.