I am trying to attach a usb device to my virtualbox node using libvirt. My node is already running, I stop my node and then I am trying to add this usb device.

I have a separate xml file defined for usb. It looks like this:

I am trying to attach it using code:

conn = libvirt.open("vbox:///session") 
    if conn ==None: 
        print 'Failed to open connection to the hypervisor' 
        sys.exit(1) 
        print 'connected to vbox hypervisor driver' 
        domainInstance = conn.lookupByName('SampleNode') 
        filed = open('/root/testFolder/usbSharedFolder.xml', 'r') 
        config_str = filed.read()
        libvirt.virDomain.attachDevice(domainInstance, config_str)