OpenStack

From the OpenStack Documentation:

"The OpenStack Open Source Cloud Mission: to produce the ubiquitous Open Source Cloud Computing platform that will meet the needs of public and private clouds regardless of size, by being simple to implement and massively scalable."

USING XAPI

The OpenStack documentation reads:

"The recommended way to use XAPI with OpenStack is through the XenAPI driver. To enable the XenAPI driver, add the following configuration options to /etc/nova/nova.conf and restart OpenStack Compute: "

compute_driver = xenapi.XenAPIDriver
xenapi_connection_url = http://your_xenapi_management_ip_address
xenapi_connection_username = root
xenapi_connection_password = your_password

"These connection details are used by the OpenStack Compute service to contact your hypervisor and are the same details you use to connect XenCenter, the XenServer management console, to your XenServer or XCP box."

While XAPI is the preferred mechanism for supporting XenServer at this time, most existing Xen Project integration into OpenStack is done through libvirt below.

USING LIBVIRT

As late as 2014, The OpenStack documentation used to read:

"It is possible to manage Xen using libvirt, though this is not well-tested or supported. To experiment using Xen through libvirt add the following configuration options /etc/nova/nova.conf:"

compute_driver = libvirt.LibvirtDriver
[libvirt]
virt_type = xen

If your documentation says something like that, it is out of date. Currently, the majority of OpenStack integrations in the market use libvirt to employ the Xen Project hypervisor. SUSE, Ubuntu, and Oracle are all using libvirt in their OpenStack implementations.

As of February of 2015, the recommendation is to install software from the latest trees of both OpenStack and libvirt to make sure that your installation has all the patches needed to make Xen Project run correctly. With current levels of software, your Xen Project-based OpenStack cloud will simply work as expected.

The minimum level of libvirt you should use is 1.2.9; earlier versions will have stability problems.

TUNING

Use the following as a guideline for configuring Xen Project software for use in OpenStack:

• Dom0 Memory:

 1-4G dom0_mem=1024M

• Dom0 vcpus:

 4 dom0_max_vcpus=4 dom0_vcpus_pin

• Use LVM for local storage:

 VOLUME_GROUP=volume_group_name

• PV vs HVM guests:

 nova image-meta set vm_mode=HVM
 nova image-meta delete vm_mode 

HOWTOs

• Learn about using Xen Project via libvirt for OpenStack "juno"
• OpenStack via DevStack, to quickly install OpenStack on a single machine.
• Getting Started document for OpenStack using Oracle VM (which uses the Xen Project Hypervisor)
• Using OpenStack with Xen Project on ARM64 on the Linaro Wiki

DOCUMENTATION

• The OpenStack documentation Introduction to Xen Project
• The OpenStack chart of Xen Project configuration options with both libvirt and XAPI/XenServer configuration parameters
• The OpenStack Wiki documentation for using Xen Project and XenServer
• The OpenStack Wiki documentation for using Xen Project via libvirt
• The OpenStack Wiki documentation of the Hypervisor Support Matrix with pointers to current OpenStack bugs when using the Xen Project Hypervisor
• The OpenStack Wiki documentation for using XenServer
• Oracle's Getting Started document for OpenStack using Oracle VM (which uses the Xen Project Hypervisor)
• The Linaro Wiki entry for using OpenStack with Xen Project on ARM64
• The NetIQ Cloud Manager 2.2 documentation for using the SUSE Xen Project Provisioning Adapter
• Thoughts on configuring XenServer (not Xen Project) for OpenStack Nova
• OpenStack Wikipedia entry

PRESENTATIONS

• Slides from the presentation Configuring OpenStack to Use the Xen Project Hypervisor from FOSDEM 2015
• Video presentation on Xen Project in OpenStack: An Overview with SUSE Cloud from Xen Project User Summit 2014
• Video presentation on Building the Rackspace Open Cloud with Xen Project and OpenStack from Xen Project User Summit 2013