Mastering KVM Virtualization

Hardware configuration examples

Let us take a look at some common hardware configurations; the domcapabilities options of virsh commands will show you the host capabilities. You can parse the output to find the exact supported value of a particular hardware configuration which you can present to a virtual machine. The following is the maximum vcpu that you can present to a VM:

[root@kvmHOST ~]# virsh domcapabilities  | grep -i max
  <vcpu max='255'/>
[root@kvmHOST ~]#

As per the output, on this host a maximum of 255 vcpus can be defined for a virtual machine:

[root@kvmHOST ~]# virsh domcapabilities  | grep diskDevice -A 5
    <enum name='diskDevice'>
      <value>disk</value>
      <value>cdrom</value>
      <value>floppy</value>
      <value>lun</value>
    </enum>
[root@kvmHOST ...