libvirtd

libvirtd is the daemon component of the libvirt virtualization API project. It provides a centralized interface for managing virtualization platforms and resources. libvirtd exposes a stable, hypervisor-agnostic API that client applications use to control domains, networks, and storage across multiple virtualization technologies such as KVM/QEMU, Xen, LXC, and OpenVZ.

Architecture and interfaces: libvirtd runs as a system daemon and communicates with clients over UNIX domain sockets or TCP, using TLS or SASL for authentication. The core library, libvirt, provides the C API and bindings for multiple languages, while client tools such as virsh and virt-manager interact with libvirtd to perform operations.

Key capabilities: the system can create, start, pause, reset, migrate, and snapshot virtual machines; manage storage pools and volumes; configure virtual networks; and monitor events and statistics. libvirt’s driver layer abstracts the specifics of each hypervisor, allowing a single API to control different backends.

Security and configuration: libvirtd can be configured to listen on local sockets by default, with optional TCP/TLS access. Access control supports Unix-based permissions, TLS certificates, and policy frameworks such as SELinux or AppArmor. The project emphasizes stability and compatibility across supported hypervisors.

Licensing and ecosystem: libvirtd is part of the libvirt project and is licensed under the GNU Lesser General Public License (LGPL) version 2.1 or later. The ecosystem includes tools like virsh, virt-manager, and web-based frontends, alongside third-party integrations that use the libvirt API.