These days there is a wide spectrum of virtualisation technologies that could in theory be used as alternatives to LXD. They differ with regard to various criteria and can divided into two main groups: traditional VM-based virtualisation tools and container-based technologies. LXD is an exception to this grouping, as it’s a hybrid approach that virtualises an entire Linux operating system using containers.
Some virtualisation tools require Linux to be used as the host system; others can run on any operating system. Some only support Linux as a guest system, while others support various systems. Many container-based technologies place the focus primarily on app virtualisation, whereas virtual machines always involve an entire operating system.
Since LXD is based on LXC, it’s possible to use a ‘naked’ LXC installation as an alternative to LXD. However, the experience will likely be less comfortable. Since there’s no daemon without LXD, virtualisation can’t be controlled on the network. And there also won’t be a REST API to serve as a uniform interface.
Among the well-known virtualisation tools, containerd is most comparable to LXD. It also works as a daemon that provides an API. This makes it possible to manage containers on the network, like with LXD. The technology is integrated in Docker and is frequently used.
In general, you should of course choose the right technology based on your specific needs. Here’s an overview of the most frequently used virtualizationvirtualisation technologies.