A bonding's primary setting is not effective

Issue

• A bonding's primary setting is not effective.  How to fix this phenomenon?

     /etc/sysconfig/network-scripts/ifcfg-bond0

BONDING_OPTS='mode=1 miimon=100 primary=eth0'

     /proc/net/bonding/bond0

Ethernet Channel Bonding Driver: v3.2.4 (January 28, 2008)

Bonding Mode: fault-tolerance (active-backup)
Primary Slave: None          <----- here
Currently Active Slave: eth3
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 0
Down Delay (ms): 0

Slave Interface: eth3
MII Status: up
Link Failure Count: 0
Permanent HW addr: XX:XX:XX:XX:XX:XX

Slave Interface: eth0
MII Status: up
Link Failure Count: 0
Permanent HW addr: XX:XX:XX:XX:XX:XX