Only schedule instances on hosts if there are sufficient CPU cores available. If this filter is not set, the scheduler may overprovision a host based on cores (i.e., the virtual cores running on an instance may exceed the physical cores).
This filter can be configured to allow a fixed amount of
vCPU overcommitment by using the cpu_allocation_ratio
Configuration option in nova.conf.
The default setting is:
cpu_allocation_ratio=16.0
With this setting, if there are 8 vCPUs on a node, the scheduler will allow instances up to 128 vCPU to be run on that node.
To disallow vCPU overcommitment set:
cpu_allocation_ratio=1.0
