LXD is a lightweight container hypervisor for full system containers, unlike Docker and Rocket which is for application containers. This means that the container will look and feel like a regular VM – but will act like a container. LXD uses the same container technology found in the Linux kernel (cgroups, namespaces, LSM, etc). The LXD project has a 2 week development cycle which many more features are coming in the future. Stéphane Graber’s blog post is a very good introduction about LXD.