instance creation fails with an error. libvirtError: Unable to add bridge

Issue

• When we try booting an instances using shell script without any interval in between two commands, boot operation fails with following error:

"libvirtError: Unable to add bridge brqab505b5c-7a port tap359ef2da-27: Device or resource busy"

• If we add some interval(say 10 sec) in between two commands then error occurs, but its rare.