Glade to hear you, sorry for so much spelling mistakes。
I update my vm os to cnetos7.6 and change my bond configuretion as:
ifcfg-bond0:
# Generated by VDSM version 4.30.9.1
DEVICE=bond0
BONDING_OPTIOS='mode=1 miion=100 downdelay=200 updelay=200'
BRIDGE=ovirtmgmt
MACADDR=a4:be:26:16:e9:b2
ONBOOT=yes
MTU=1500
DEFROUTE=no
NM_CONTROLLED=no
IPV6INIT=no
And there are no 'ifcfg-XXX.bkp' in the network-scripts folder。
But the vm still unreachable when bond link change。
When I plug the second NIC out,the message puts:
localhost kernel: bond0 :Releasing backup interface eno1
localhost kernel: device eno1 left promiscuous mode
localhost kernel: bond0 : making interface eno2 the new active one
localhost kernel: device eno2 entered promiscuous mode
localhost kernel: i40e 0000:1a:00.0 eno1: returing to hw mac address a4:be:26:16:e9:b1
localhost lldpad: recvfrom(Event interface) : No buffer space availabe