How Do I Customize Properties When Creating a VM on oVirt?

Symptom

During VM creation, a custom property qemu:commandline is desired, but this custom property is not included in the list of recognized keywords.

Key Process and Cause Analysis

The XML configuration of an oVirt-based VM cannot be manually modified. To enable various VM configurations, oVirt allows property customization. The official built-in custom properties do not contain qemu:commandline. However, the vdsm-hook-qemucmdline extension package is provided, which requires manual installation and configuration.

Conclusion and Solution

Currently, vdsm-hook-qemucmdline supports only the qemu:arg subtag. If you want to enable other qemucmdline property tags, you can modify the /usr/libexec/vdsm/hooks/before_vm_start/50_qemucmdline script to customize the property configuration.
If you want to enable other custom properties, create and add custom attributes and hook scripts by referring to the official document.

Install the extension package.

        
             yum install vdsm-hook-qemucmdline.noarch

Add customized properties.

        
             engine-config -s "UserDefinedVMProperties=qemu_cmdline=^.*$" --cver=4.4

Restart the ovirt-engine service.
1

service ovirt-engine restart

The following is an example.

Access the oVirt web page, choose New Virtual Machine > Custom Properties > qemu_cmdline, and enter the following content:

["-chardev","socket,path=/tmp/vm_sock0,server=on,wait=off,id=vm_sock","-device","virtio-serial","-device","virtserialport,chardev=vm_sock,name=serialport0"]

After the VM is created and started, run the virsh dumpxml command to check the VM configuration. The following content is added to the VM configuration.

<qemu:commandline>
  <qemu:arg value='-chardev'/>
  <qemu:arg value='socket,path=/tmp/vm_sock0,server=on,wait=off,id=vm_sock'/>
  <qemu:arg value='-device'/>
  <qemu:arg value='virtio-serial'/>
  <qemu:arg value='-device'/>
  <qemu:arg value='virtserialport,chardev=vm_sock,name=serialport0'/>
</qemu:commandline>

Parent topic: oVirt