code: func (fc FirewalldCheck) Check() (warnings, errorList []error) {
  	klog.V(1).Infoln("validating if the firewall is enabled and active")
  	initSystem, err := initsystem.GetInitSystem()
  	if err != nil {
  		return []error{err}, nil
  	}
  
  	warnings = []error{}
  
  	if !initSystem.ServiceExists("firewalld") {
  		return nil, nil
  	}
  
  	if initSystem.ServiceIsActive("firewalld") {
  		warnings = append(warnings,
  			errors.Errorf("firewalld is active, please ensure ports %v are open or your cluster may not function correctly",
  				fc.ports))
  	}
  
  	return warnings, errorList
  }
docs: // Check validates if the firewall is enabled and active.