Rocks 5.1 Frontend only one core appears?

Hi,

I am installing the rocks 5.1 on my dual quad core cluster. When I installed the frontend, I noticed that there are only 1 core there, where it should be 8 cores.
(cat /proc/cpuinfo)
What's wrong?
What I should do?

Thanks

are you using SMP kernel? the kernel you are running may not be configured to use more than 1 processor