The idea is to integrate LXD into OpenStack as a "lightweight VM". So, LXD runs a system with a full init system and executes them inside of a Linux Container. Another term for this is a "system container".

Kubernetes is designed for running Application Container images (e.g. docker, oci, appc) and in this case those containers are running not as Linux containers on a shared Kernel but inside of a VM with Xen/Hypernetes. Another implementation of this "app container in a VM" concept is Clear Containers which is available in rkt[1] and can, like Hyper, run the application container image formats (docker/appc).

This is all a bit confusing so let me know if this helps :)

[1] https://coreos.com/blog/rkt-0.8-with-new-vm-support/

They're pretty much the exact opposite of each other. LXD is something that runs things that look like VM images when they're actually running the same kernel - this is creating full (albeit lightweight) VMs to run container images.

The broad approach isn't new (https://clearlinux.org/features/clear-containers describes Intel's Clear Containers work which allows you to use rkt to run containers in individual lightweight VMs), but the trick in this case is to perform the isolation at the pod level (ie, a collection of functionally related containers) rather than the individual container level.

(Edit: Apparently the Docker support for Clear Containers hasn't gone upstream, so dropped the reference to it)

And another different side of HyperContainer is that it follows OCI spec, check the runv project here: https://github.com/hyperhq/runv/, so technically speaking, it's a hypervisor version of OCI, just like docker is a linux container version of OCI. Seems rkt/clear linux or LXD does not.

LXD = VM-like Linux container HyperContaineer = (Docker) Container-like ultra-light VM

Make sense?

Awesome guys, that helps a lot. Thanks for the info and links.