2.4. Installing Guest Agents and Drivers

2.4.1. Red Hat Virtualization Guest agents, tools, and drivers

The Red Hat Virtualization guest agents, tools, and drivers provide additional functionality for virtual machines, such as gracefully shutting down or rebooting virtual machines from the VM Portal and Administration Portal. The tools and agents also provide information for virtual machines, including:

  • Resource usage
  • IP addresses

The guest agents, tools and drivers are distributed as an ISO file that you can attach to virtual machines. This ISO file is packaged as an RPM file that you can install and upgrade from the Manager machine.

You need to install the guest agents and drivers on a virtual machine to enable this functionality for that machine.

Table 2.1. Red Hat Virtualization Guest drivers

DriverDescriptionWorks on

virtio-net

Paravirtualized network driver provides enhanced performance over emulated devices like rtl.

Server and Desktop.

virtio-block

Paravirtualized HDD driver offers increased I/O performance over emulated devices like IDE by optimizing the coordination and communication between the virtual machine and the hypervisor. The driver complements the software implementation of the virtio-device used by the host to play the role of a hardware device.

Server and Desktop.

virtio-scsi

Paravirtualized iSCSI HDD driver offers similar functionality to the virtio-block device, with some additional enhancements. In particular, this driver supports adding hundreds of devices, and names devices using the standard SCSI device naming scheme.

Server and Desktop.

virtio-serial

Virtio-serial provides support for multiple serial ports. The improved performance is used for fast communication between the virtual machine and the host that avoids network complications. This fast communication is required for the guest agents and for other features such as clipboard copy-paste between the virtual machine and the host and logging.

Server and Desktop.

virtio-balloon

Virtio-balloon is used to control the amount of memory a virtual machine actually accesses. It offers improved memory overcommitment.

Server and Desktop.

qxl

A paravirtualized display driver reduces CPU usage on the host and provides better performance through reduced network bandwidth on most workloads.

Server and Desktop.

Table 2.2. Red Hat Virtualization Guest agents and tools

Guest agent/toolDescriptionWorks on

ovirt-guest-agent-common

Enables the Red Hat Virtualization Manager to receive internal virtual machine events and information such as IP address and installed applications. Also enables the Manager to execute specific commands on a virtual machine, such as shut down or reboot.

On virtual machines running Red Hat Enterprise Linux 6 or 7, ovirt-guest-agent-common installs tuned on your virtual machine and configures it to use an optimized, virtual machine profile. Use qemu-guest-agent on Red Hat Enterprise Linux 8 virtual machines

Server and Desktop.

qemu-guest-agent

Used instead of ovirt-guest-agent-common on Red Hat Enterprise Linux 8 virtual machines. It is installed and enabled by default.

Server and Desktop.

spice-agent

The SPICE agent supports multiple monitors and is responsible for client-mouse-mode support to provide a better user experience and improved responsiveness than the QEMU emulation. Cursor capture is not needed in client-mouse-mode. The SPICE agent reduces bandwidth usage when used over a wide area network by reducing the display level, including color depth, disabling wallpaper, font smoothing, and animation. The SPICE agent enables clipboard support allowing cut and paste operations for both text and images between client and virtual machine, and automatic guest display setting according to client-side settings. On Windows-based virtual machines, the SPICE agent consists of vdservice and vdagent.

Server and Desktop.

rhev-sso

An agent that enables users to automatically log in to their virtual machines based on the credentials used to access the Red Hat Virtualization Manager.

Desktop.

2.4.2. Installing the Guest Agents and Drivers on Red Hat Enterprise Linux

The Red Hat Virtualization guest agents and drivers are provided by the Red Hat Virtualization Agent repository.

Note

Red Hat Enterprise Linux 8 virtual machines use the qemu-guest-agent service, which is installed and enabled by default, instead of the ovirt-guest-agent service. If you need to manually install the guest agent on RHEL 8, follow the procedure below.

Procedure

  1. Log in to the Red Hat Enterprise Linux virtual machine.
  2. Enable the Red Hat Virtualization Agent repository:

    • For Red Hat Enterprise Linux 6

      # subscription-manager repos --enable=rhel-6-server-rhv-4-agent-rpms
    • For Red Hat Enterprise Linux 7

      # subscription-manager repos --enable=rhel-7-server-rh-common-rpms
    • For Red Hat Enterprise Linux 8

      # subscription-manager repos --enable=rhel-8-for-x86_64-appstream-rpms
  3. Install the guest agent and dependencies:

    • For Red Hat Enterprise Linux 6 or 7, install the ovirt guest agent:

      # yum install ovirt-guest-agent-common
    • For Red Hat Enterprise Linux 8, install the qemu guest agent:

      # yum install qemu-guest-agent
  4. Start and enable the ovirt-guest-agent service:

    • For Red Hat Enterprise Linux 6

      # service ovirt-guest-agent start
      # chkconfig ovirt-guest-agent on
    • For Red Hat Enterprise Linux 7

      # systemctl start ovirt-guest-agent
      # systemctl enable ovirt-guest-agent
  5. Start and enable the qemu-guest-agent service:

    • For Red Hat Enterprise Linux 6

      # service qemu-ga start
      # chkconfig qemu-ga on
    • For Red Hat Enterprise Linux 7 or 8

      # systemctl start qemu-guest-agent
      # systemctl enable qemu-guest-agent

The guest agent now passes usage information to the Red Hat Virtualization Manager. You can configure the guest agent in the /etc/ovirt-guest-agent.conf file.