Libvirt

Linux virtualization tool

Tips

List of domain

# virsh list --all

Update config of VM

# virsh edit <VM>

Clone VM

Note: VM have to stopped

# virt-clone --original <name_of_vm> --name <name_of_vm> --file <new_path_to_image_vm>

Extend disk on the fly

Shutdown VM isn't require

• Identify disk, which do you want to extend

# virsh domblklist <name_of_vm>
 Target   Source
--------------------------------
 vda      /volumes/disk01.qcow2

• Using name for Target and VM name define a new size.

Usually size define in KB

# virsh blockresize <name_of_vm> vda 500G
Block device 'vda' is resized

• Check updated size

# qemu-img info /volumes/disk01.qcow2 --force-share

Troubleshouting

Case 01. In during starting VM in cockpit-ui or Terraform deploy Libvirt return error:

• System information:
  • Ubuntu 20.04
  • Apparmor
  • Libvirt

libvirtd[18883]: internal error: qemu unexpectedly closed the monitor: 2023-03-27T11:31:54.139065Z qemu-system-x86_64: -blockdev {"driver":"file","filename":"/volumes/disk01.qcow2","node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}: Could not open '/volumes/disk01.qcow2': Permission denied

Just update Apparmor template: /etc/apparmor.d/libvirt/TEMPLATE.qemu

Example fix:

#include <tunables/global>

profile LIBVIRT_TEMPLATE flags=(attach_disconnected) {
  #include <abstractions/libvirt-qemu>
  "/volumes/{,**}" rwk, # <- Add the line
}