KVM Virtual Machine XML Configuration Example

External

• https://libvirt.org/formatdomain.html

Internal

• Linux Virtualization Concepts

Example

<domain type='kvm'>
  <name>template</name>
  <uuid>2a0523ba-9c44-47bd-8956-fc2b93ac1863</uuid>
  <memory unit='KiB'>1048576</memory>
  <currentMemory unit='KiB'>1048576</currentMemory>
  <vcpu placement='static'>1</vcpu>
  <os>
      <type arch='x86_64' machine='pc-i440fx-rhel7.0.0'>hvm</type>
      <boot dev='hd'/>
  </os>
  <features>
      <acpi/>
      <apic/>
  </features>
  <cpu mode='custom' match='exact'>
      <model fallback='allow'>Broadwell</model>
  </cpu>
  <clock offset='utc'>
      <timer name='rtc' tickpolicy='catchup'/>
      <timer name='pit' tickpolicy='delay'/>
      <timer name='hpet' present='no'/>
  </clock>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <pm>
      <suspend-to-mem enabled='no'/>
      <suspend-to-disk enabled='no'/>
  </pm>
  <devices>
      <emulator>/usr/libexec/qemu-kvm</emulator>
      <disk type='file' device='cdrom'>
          <driver name='qemu' type='raw'/>
          <target dev='hda' bus='ide'/>
          <readonly/>
          <address type='drive' controller='0' bus='0' target='0' unit='0'/>
      </disk>
      <disk type='file' device='cdrom'>
          <driver name='qemu' type='raw'/>
          <target dev='hdb' bus='ide'/>
          <readonly/>
          <address type='drive' controller='0' bus='0' target='0' unit='1'/>
      </disk>
   <disk type='file' device='disk'>
     <driver name='qemu' type='qcow2'/>

     <target dev='vda' bus='virtio'/>
     <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
   </disk>
   <disk type='file' device='disk'>
     <driver name='qemu' type='raw'/>

     <target dev='vdb' bus='virtio'/>
     <address type='pci' domain='0x0000' bus='0x00' slot='0x08' function='0x0'/>
   </disk>
   <controller type='usb' index='0' model='ich9-ehci1'>
     <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x7'/>
   </controller>
   <controller type='usb' index='0' model='ich9-uhci1'>
     <master startport='0'/>
     <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0' multifunction='on'/>
   </controller>
   <controller type='usb' index='0' model='ich9-uhci2'>
     <master startport='2'/>
     <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x1'/>
   </controller>
   <controller type='usb' index='0' model='ich9-uhci3'>
     <master startport='4'/>
     <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x2'/>
   </controller>
   <controller type='pci' index='0' model='pci-root'/>
   <controller type='ide' index='0'>
     <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
   </controller>
   <controller type='virtio-serial' index='0'>
     <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
   </controller>
   <interface type='network'>
     <mac address='52:54:00:79:03:0c'/>

     <model type='virtio'/>
     <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
   </interface>
   <serial type='pty'>
     <target port='0'/>
   </serial>
   <console type='pty'>
     <target type='serial' port='0'/>
   </console>
   <channel type='unix'>
     <target type='virtio' name='org.qemu.guest_agent.0'/>
     <address type='virtio-serial' controller='0' bus='0' port='1'/>
   </channel>
   <input type='tablet' bus='usb'>
     <address type='usb' bus='0' port='1'/>
   </input>
   <input type='mouse' bus='ps2'/>
   <input type='keyboard' bus='ps2'/>
   <memballoon model='virtio'>
     <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
   </memballoon>
 </devices>
</domain>

Elements

name

The short name of the virtual machine. Must consists of alphanumeric characters and it must be unique per virtualization host. Ideally, it should follow the virtual machine name convention when naming virtual machine. Also conventionally, it is also the name of the file storing the virtual machine image, with the ".img" prefix.

uuid

uuid is a globally unique identifier for the virtual machine. Must be in a RFC 4122-compliant format. Can be committed when defining a new machine. If omitted, a new UUID will be generated.

memory

memory represents the maximum amount of memory allocated to the guest at boot time. Valid units are "b" (bytes), "KB" (kilobytes - 1,000 bytes), "KiB" (kibibytes 1,024 bytes), "MB", "MiB", 'GB", "GiB", "TB", "TiB". However, the value will be rounded up to the nearest KiB by libvirt, and may be further rounded up to the granularity supported by the hypervisor. In case NUMA is configured for the guest, the memory element can be omitted.

currentMemory

currentMemory represents the actual allocation of memory for the guest. This value can be less than the maximum allocation, to allow for ballooning up the guests memory on the fly. If this is omitted, it defaults to the same value as the memory element. The unit attribute behaves the same as for memory.

maxMemory

See https://libvirt.org/formatdomain.html#elementsMemoryAllocation.

vcpu

vcpu defines the maximum number of virtual CPUs allocated. It must be 1 and the maximum number supported by the hypervisor.

More details: https://libvirt.org/formatdomain.html#elementsCPUAllocation.