Introduction

Linux Containers (LXC) is a lightweight system virtualization that uses resource isolation instead of the hardware emulation approach used by KVM and Xen. For users who do not require full OS virtualization as provided by KVM and Xen, container technologies such as LXC provide an attractive performant solution for virtualization.

Cloudstack currently does not support containers such as LXC and OpenVZ.

Purpose

This docoument contains the design specification for LXC support in Cloudstack.

References

http://sourceforge.net/mailarchive/message.php?msg_id=28030821

Feature Specification

LXC will be implemented as a hypervisor in Cloudstack and will be a first class citizen to the other hypervisors such as Xen, KVM, VMWare. As such, a user will be able to select LXC as the hypervisor for all areas a hypervisor is selectable and where the system resources have been met.

LXC will leverage the code found in the Libvirt classes which is currently used for KVM. Some of the Libvirt and Kvm classes will be refactored for code reusablility.

Secondary storage

LXC template images will be stored as a tar format.

Primary storage

TODO: investigate options or if this should always remain local

System VMs

Each of the different hypervisors currently have their own System VMs. These system VM images are used to run the console proxy VM and the secondary storage VM.

One proposal is to make the console proxy optional and run the secondary storage daemon on baremetal (next ot the management server)

API

TODO: investigate