Hello, I have an Openstack cluster which was created using devstack. And recently I was involved in project in which there is a dependency on SSSE3 cpu flag in an Openstack VM instance, to accomplish certain tasks. I searched many posts but couldn't find a definitive solution. The suggestion mentioned didn't worked for me either. I have added below in /etc/nova/nova.conf and restarted devstack@n-cpu.service cpu_mode = host-model cpu_model_extra_flags = ssse3 Please let me know a possible way to enable SSSE3 cpu flag in a vm instance. Thanks, Tarun