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 Driver Description Works 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/tool Description Works on 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. 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 Log in to the Red Hat Enterprise Linux virtual machine. 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 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 and 9, install the qemu guest agent: # yum install qemu-guest-agent 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 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, 8 or 9 # 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 oVirt guest agent in the /etc/ovirt-guest-agent.conf file.

Commands:
subscription-manager repos --enable=rhel-6-server-rhv-4-agent-rpms
subscription-manager repos --enable=rhel-7-server-rh-common-rpms
subscription-manager repos --enable=rhel-8-for-x86_64-appstream-rpms
yum install ovirt-guest-agent-common
yum install qemu-guest-agent
service ovirt-guest-agent start chkconfig ovirt-guest-agent on
systemctl start ovirt-guest-agent systemctl enable ovirt-guest-agent
service qemu-ga start chkconfig qemu-ga on
systemctl start qemu-guest-agent systemctl enable qemu-guest-agent