...

The cluster is installed with a real-time kernel on each node. It must execute orders without delay. So, some CPUs should be isolated from the scheduler kernel run with isolcpus kernel parameter.

• To specify some CPU:

isolcpus=<cpu number>,...,<cpu number>

• To specify a range of CPU is:

isolcpus=<cpu number>-<cpu number>

...

some parameters:

• isolcpus parameter: Isolate some CPUs from the scheduler. It's the value of cpumachinesrt.
• rcu_nocbs parameter: Remove one or more CPUsfrom candidates for running callbacks. It's the value of cpumachinesrt.

VM configuration

The official documentation on the XML format of libvirt is here.

...