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Libvirt virsh and virt-manager

Libvirt virsh and virt-manager

Definition

libvirt is a virtualization management API. virsh is a command-line interface to it. virt-manager is a graphical management application built on libvirt.

How the lecture connects the layers

virsh / virt-manager / other management tools
                  -> libvirt
                  -> QEMU/KVM or another supported backend
                  -> VM

This is a management path, not the path every guest instruction or packet follows.

Responsibilities in the slides

  • Provision, create, modify, monitor, start/stop, and migrate domains.
  • Represent a virtual hardware profile in XML.
  • Configure storage pools and networks.
  • Manage local or remote hypervisors.
  • Inspect performance and resource utilization through virt-manager.
  • View the guest console through the GUI’s embedded viewer.

Domain is libvirt’s term for the managed VM environment in this context.

Study example: hardware profile

The XML excerpt on PDF page 85 / printed slide 91 names a domain, gives it 1,048,576 KiB of memory and one vCPU, specifies an x86_64 guest machine, and points to a QEMU emulator. That memory quantity is 1 GiB.

The excerpt is partial; its old machine type and executable path are not assumed to match an installed system.

Networking and Vagrant boundaries

The deck briefly names bridges, NAT, physical interfaces, dnsmasq for DNS/DHCP, and bridge-management tools. It defers detail to dedicated networking slides. Vagrant is mentioned as infrastructure as code without a developed workflow, so no configuration guide is inferred from that one slide.

Common mistakes

  • Calling libvirt the CPU hypervisor or emulator.
  • Treating virsh and virt-manager as unrelated VM execution engines.
  • Assuming all libvirt backends expose identical features.
  • Reading an XML profile as proof that the host has spare capacity to satisfy it.

Related: QEMU and KVM, Virtual Machines and Hypervisors, VM Migration - Cold Hot and Live.

Source

Lecture 03 PDF pages 84-90 (printed slides 90-96). Context: Lecture 03 - Computing Virtualization Technologies and Tools. Layer diagram, unit conversion, and common mistakes are study explanations.

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