1) Calculate Threads, Core and Socket $ lscpu | grep -i -E "^CPU\(s\):|core|socket" CPU(s): 8 Thread(s) per core: 2 Core(s) per socket: 4 Socket(s): 1 Model name: Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz 2) vCPU calculation: vCPU = Thread(s) per core * Core(s) per socket * Socket(s) vCPU = 2 *4 * 1 =8 3) Over Commiting Ratio : Dependends on CPU model can be increased upto 16 vCPUS nova.conf in compute node [DEFAULT] ...