Libvirt.md

libvirt

How to create VM

Example:

lvcreate --size 20G --name lv_vm_example_01 vg1

virt-install \
    --connect qemu:///system \
    --name example-01 \
    --ram 2048 \
    --vcpus 1 \
    --location http://http.debian.net/debian/dists/stable/main/installer-amd64/ \
    --file /dev/mapper/vg1-lv_vm_example_01 \
    --virt-type kvm \
    --os-type linux --os-variant debianwheezy \
    --network network=default \
    --graphics vnc,port=5901,listen=127.0.0.1,password=xxx \
    --noautoconsole

virsh autostart example-01

virt-viewer -c qemu:///system example-01
virt-viewer -c qemu+ssh://root@example.com/system example-01

Faster disk I/O

Not for production - guest file system may become corrupt if guest operating system is not terminated gracefully.

virsh edit example-01

Add the parameter cache='unsafe':

<domain type='kvm'>
   ...
   <devices>
     <disk type='file' device='disk'>
       <driver name='qemu' type='qcow2' cache='unsafe'/>
       ...
     </disk>
   </devices>
   ...
</domain>