firecracker-microvm/firecracker · error

Failed to start the event manager

Error message

Failed to start the event manager

What it means

Error "Failed to start the event manager" thrown in firecracker-microvm/firecracker.

Source

Thrown at src/firecracker/src/main.rs:674

    // INVARIANT: seccomp must be applied before entering the event loop.
    vmm::seccomp::apply_filter(
        seccomp_filters
            .get("vmm")
            .ok_or(RunWithoutApiError::MissingSeccompFilter)?,
    )
    .map_err(RunWithoutApiError::SeccompFilter)?;

    // Start the metrics.
    firecracker_metrics
        .lock()
        .expect("Poisoned lock")
        .start(metrics::WRITE_METRICS_PERIOD_MS);

    // Run the EventManager that drives everything in the microVM.
    loop {
        event_manager
            .run()
            .expect("Failed to start the event manager");

        match vmm.lock().unwrap().shutdown_exit_code() {
            Some(FcExitCode::Ok) => break,
            Some(exit_code) => return Err(RunWithoutApiError::Shutdown(exit_code)),
            None => continue,
        }
    }
    Ok(())
}

View on GitHub (pinned to 0a745def42)

Solutions

1. Check the event manager's subscriber registrations and fd state before run; a bad fd causes run to fail.
2. Inspect the underlying error returned by EventManager::run for the precise cause.

When it happens

Trigger: Thrown at src/firecracker/src/main.rs:674 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of firecracker-microvm/firecracker@0a745def42 (2026-08-19). Data as JSON: /api/errors/65b105366a0dc1f8. Report an issue: GitHub.