- you have enabled Virtualization (VT-x or AMD-V) in the computer BIOS
- the CPU flags, should then contain virtualization flags, please try:
- for Intel: grep vmx /proc/cpuinfo
- for AMD: grep sv /proc/cpuinfo
- the KVM modules are loaded (kvm_intel for Intel or kvm_amd for AMD)
Most likely the first point is the root cause here.
Thanks. I am able to figure it out. I am using nested virtualization. ESXi are base hypervisior layer and on the top of it i had build Opennebula using CentOS 7. I had forgot yo enable VT at ESX level for the CentOS machine.