how to create guest with /dev/vda ROOT volume?

[Yiping Zhang]

Hi, All:

My CloudStack environment is 4.3.0 running on rhel 6.5 and kvm hypervisor also 
running rhel 6.5.

When I create my  first VM from an imported rhel 6.5 ISO image,  the root 
volume is identified as /dev/sda.  Is there a way to force the root volume to 
be identified as  /dev/vda device ? How do you create guest VM with /dev/vda 
root volume?

Thanks

Yiping