This is how I resolved:
I removed all the network interfaces in OMV webgui, but I forgot to add a backup interface before did this.
Therefore, I end up added my eth0 manually in the /etc/network/interface. (My server has a monitor and keyboard).
I then reboot OMV, and went back into OMV webgui to re-create my bond0.
So far, so good !
@ikogan,
Thanks for your help.