This document discusses Project Kronos, which aims to port the Xen API (XAPI) to Linux distributions like Ubuntu and Debian in order to more easily integrate the Xen hypervisor with OpenStack. It notes that Kronos allows OpenStack's compute service (Nova) to run directly on the management domain (Dom0) of Xen hosts. The document outlines Kronos' current status and roadmap, and invites input from the OpenStack community on potential conflicts or issues with running Nova on Dom0 versus in a guest VM. It also compares Kronos to existing Xen-based solutions like XCP and XenServer.

1. Integrating Xen and OpenStack
with Project Kronos
OpenStack Essex Design Summit
October 5, 2011
Todd Deshane
Xen.org

2. Xen and OpenStack Overview
● XCP and XenServer
○ XenAPI driver
○ Compute installed in a guest (DomU)
● Project Kronos
○ XenAPI driver
○ Compute node installed on management domain (Dom0)
● Xen hypervisor
○ libvirt driver possible
○ Note that XenAPI has a lot more features than libvirt
(See discussion: http://wiki.openstack.org/XenAPI)

3. Project Kronos
● Port Xen API (XAPI) to Linux distributions
○ Debian and Ubuntu first
○ Fedora next
● Phase 1 timeline
○ Ubuntu PPAs of XAPI packages for Ubuntu 11.10
○ Simultaneously, push packages to Debian unstable
● Phase 2 timeline
○ Ubuntu 12.04 LTS blueprint
○ Project Kronos developers @ UDS

4. Pros and Cons of Nova in Dom0
Cons
Pros
● Shares resources with
● Ease of management Dom0
● Package install ● Less isolation
● Shares auth/networking ○ Nova problem could
● Direct access to all VM affect Dom0 or other
operations VMs
● Simpler solution in
general
● Great for development
● Easy proof of concept
(install on existing distro)

5. Pros and Cons of Nova in a VM
Pros Cons
● Can be installed/updated ● Additional auth/network
as a brand new VM for every host
● Can be deployed in ● Another layer of
similar manner to VMs complexity
● Isolation ○ System administration
○ Decoupled ○ Indirect access for VM
dependencies operations
○ Dom0 and other VMs
not affected by Nova
● Restartable Nova VM
● Dedicated VM resources

6. Project Kronos vs. XCP/XenServer
● Project Kronos
○ Simpler for new users (deployers)
○ Start from distribution (Ubuntu, etc.)
○ Nova in Dom0 potential isolation issue
● XCP/XenServer
○ More effort to set up initially (especially for new users)
○ Start from pre-packaged distribution
○ Nova in VM model is still a great option

7. Project Kronos - Current Status
● Working Debian packages and repo
○ http://wiki.xen.org/xenwiki/XAPI_on_debian
● Work items and manpower breakdown
○ http://bit.ly/n5wQca
● Ubuntu Developer Summit planning in progress

8. Project Kronos and You
● Still under development, but functional
○ Any testing is welcome (report issues on xen-api mailing
list)
● Working OpenStack packages in Debian unstable would be
nice to have (could apt-get install everything)
● Packaging help is always appreciated
○ RHEL port in progress (Xen community member)
○ Ubuntu packages of our Debian ones
○ Interest in Fedora and other distributions?
● Any OpenStack/xapi conflicts?
○ xapi uses port 80 for management (stunnel for HTTPS)
○ Other potential issues or conflicts?
● More info: http://blog.xen.org/index.php/2011/07/22/project-
kronos/

9. http://etherpad.openstack.org/kronos