Installing the QEMU guest agent and VirtIO drivers - Virtual machines | Virtualization

Installing the QEMU guest agent
- Installing QEMU guest agent on a Linux virtual machine
- Installing QEMU guest agent on a Windows virtual machine
Installing VirtIO drivers

The QEMU guest agent is a daemon that runs on the virtual machine and passes information to the host about the virtual machine, users, file systems, and secondary networks.

Installing the QEMU guest agent

Installing QEMU guest agent on a Linux virtual machine

The qemu-guest-agent is widely available and available by default in Fedora virtual machines (VMs). Install the agent and start the service.

To create snapshots of an online (Running state) VM with the highest integrity, install the QEMU guest agent.

The QEMU guest agent takes a consistent snapshot by attempting to quiesce the VM’s file system as much as possible, depending on the system workload. This ensures that in-flight I/O is written to the disk before the snapshot is taken. If the guest agent is not present, quiescing is not possible and a best-effort snapshot is taken. The conditions under which the snapshot was taken are reflected in the snapshot indications that are displayed in the web console or CLI.

Procedure

Access the virtual machine command line through one of the consoles or by SSH.
Install the QEMU guest agent on the virtual machine:
```
$ yum install -y qemu-guest-agent
```
Ensure the service is persistent and start it:
```
$ systemctl enable --now qemu-guest-agent
```

Verification

Run the following command to verify that AgentConnected is listed in the VM spec:
```
$ oc get vm <vm_name>
```

Installing QEMU guest agent on a Windows virtual machine

For Windows virtual machines, the QEMU guest agent is included in the VirtIO drivers. Install the drivers on an existing or a new Windows installation.

To create snapshots of an online (Running state) VM with the highest integrity, install the QEMU guest agent.

Procedure

In the Windows Guest Operating System (OS), use the File Explorer to navigate to the guest-agent directory in the virtio-win CD drive.
Run the qemu-ga-x86_64.msi installer.

Verification

Run the following command to verify that the output contains the QEMU Guest Agent:
```
$ net start
```

Installing VirtIO drivers

Supported VirtIO drivers for Microsoft Windows virtual machines

Supported drivers
Driver name	Hardware ID	Description
viostor	VEN_1AF4&DEV_1001 VEN_1AF4&DEV_1042	The block driver. Sometimes displays as an SCSI Controller in the Other devices group.
viorng	VEN_1AF4&DEV_1005 VEN_1AF4&DEV_1044	The entropy source driver. Sometimes displays as a PCI Device in the Other devices group.
NetKVM	VEN_1AF4&DEV_1000 VEN_1AF4&DEV_1041	The network driver. Sometimes displays as an Ethernet Controller in the Other devices group. Available only if a VirtIO NIC is configured.

About VirtIO drivers

VirtIO drivers are paravirtualized device drivers required for Microsoft Windows virtual machines to run in OKD Virtualization. The supported drivers are available in the container-native-virtualization/virtio-win container disk of the Red Hat Ecosystem Catalog.

The container-native-virtualization/virtio-win container disk must be attached to the virtual machine as a SATA CD drive to enable driver installation. You can install VirtIO drivers during Windows installation on the virtual machine or added to an existing Windows installation.

After the drivers are installed, the container-native-virtualization/virtio-win container disk can be removed from the virtual machine.

Installing VirtIO drivers on an existing Windows virtual machine

Install the VirtIO drivers from the attached SATA CD drive to an existing Windows virtual machine.

This procedure uses a generic approach to adding drivers to Windows. The process might differ slightly between versions of Windows. See the installation documentation for your version of Windows for specific installation steps.

Procedure

Start the virtual machine and connect to a graphical console.
Log in to a Windows user session.
Open Device Manager and expand Other devices to list any Unknown device.
1. Open the Device Properties to identify the unknown device. Right-click the device and select Properties.
2. Click the Details tab and select Hardware Ids in the Property list.
3. Compare the Value for the Hardware Ids with the supported VirtIO drivers.
Right-click the device and select Update Driver Software.
Click Browse my computer for driver software and browse to the attached SATA CD drive, where the VirtIO drivers are located. The drivers are arranged hierarchically according to their driver type, operating system, and CPU architecture.
Click Next to install the driver.
Repeat this process for all the necessary VirtIO drivers.
After the driver installs, click Close to close the window.
Reboot the virtual machine to complete the driver installation.

Installing VirtIO drivers during Windows installation

Install the virtio drivers during or after Windows installation.

This procedure uses a generic approach to the Windows installation and the installation method might differ between versions of Windows. See the documentation for the version of Windows that you are installing.

Prerequisites

A storage device containing the virtio drivers must be attached to the VM.

Procedure

In the Windows Guest OS, use the File Explorer to navigate to the virtio-win CD drive.
Double-click to run the appropriate installer for your VM:
1. For a 64-bit vCPU, use the virtio-win-gt-x64 installer. 32-bit vCPUs are no longer supported.
Optional: During the Custom Setup step of the installer, select the device drivers you want to install. The recommended driver set is selected by default.
After the installation is complete, select Finish.
Reboot the VM.

Verification

Open the system disk on the PC. This is typically C:.
Navigate to Program Files → Virtio-Win.

If the Virtio-Win directory is present and contains a sub-directory for each driver, the installation was successful.

Adding VirtIO drivers container disk to a virtual machine

OKD Virtualization distributes VirtIO drivers for Microsoft Windows as a container disk, which is available from the Red Hat Ecosystem Catalog. To install these drivers to a Windows virtual machine, attach the container-native-virtualization/virtio-win container disk to the virtual machine as a SATA CD drive in the virtual machine configuration file.

Prerequisites

Download the container-native-virtualization/virtio-win container disk from the Red Hat Ecosystem Catalog. This is not mandatory, because the container disk will be downloaded from the Red Hat registry if it not already present in the cluster, but it can reduce installation time.

Procedure

Add the container-native-virtualization/virtio-win container disk as a cdrom disk in the Windows virtual machine configuration file. The container disk will be downloaded from the registry if it is not already present in the cluster.

spec:
  domain:
    devices:
      disks:
        - name: virtiocontainerdisk
          bootOrder: 2 (1)
          cdrom:
            bus: sata
volumes:
  - containerDisk:
      image: container-native-virtualization/virtio-win
    name: virtiocontainerdisk

1 OKD Virtualization boots virtual machine disks in the order defined in the VirtualMachine configuration file. You can either define other disks for the virtual machine before the container-native-virtualization/virtio-win container disk or use the optional bootOrder parameter to ensure the virtual machine boots from the correct disk. If you specify the bootOrder for a disk, it must be specified for all disks in the configuration.

The disk is available once the virtual machine has started:
- If you add the container disk to a running virtual machine, use oc apply -f <vm.yaml> in the CLI or reboot the virtual machine for the changes to take effect.
- If the virtual machine is not running, use virtctl start <vm>.

After the virtual machine has started, the VirtIO drivers can be installed from the attached SATA CD drive.