Comment 3 for bug 1836969

The recommendation to address this issue is to disable DAD on the internal management network interface. This would involve setting the net.ipv6.conf.<interface>.accept_dad=0 for the interface as part of a pre_up configuration step.

To handle the dynamically created interfaces, an additional pre_up configuration entry will be required to first create the device. For example, in the bonding case the following pre_up entry would pre-create the interface so that the sysctl can be set for that interface.

echo +bond1 > /sys/class/net/bonding_masters

The only alternative is to patch the ifup scripts to add support for setting this specific sysctl or to create a hook to run a sysctl prior to IPv6 address creation.