1. OpenStack and Xen
Stefano Stabellini & Anthony Perard
Feb 2015

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Why Xen?
Xen is a type-1 hypervisor
small footprint (Less then 100K LOC)
GPLv2
Powers the largest public cloud in production
(>50% of vendors listed in Gartner 2014 Cloud magic
quadrant, more in terms of hosts)

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Make Xen the best hypervisor for OpenStack

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OpenStack

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OpenStack

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OpenStack

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OpenStack

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OpenStack

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OpenStack

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OpenStack

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OpenStack

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Status and Goals
Xen via Libvirt is currently in Group C
Goals:
• Xen should be a great platform for OpenStack production deployments
• Get Xen via Libvirt in Group A within 1 year
• Xen should be a great platform for OpenStack development and hacking
• devstack should deploy Xen and OpenStack

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From 0 to Xen and OpenStack
1. Install Ubuntu 14.04 LTS
2. Install Xen
apt-get install xen-hypervisor-4.4-amd64
3. git clone devstack && configure it to use Xen
LIBVIRT_TYPE=xen
4. ./stack.sh

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From 0 to Xen and OpenStack
What we actually did
1. Install Ubuntu 14.04 LTS
2. Install Xen
apt-get install xen-hypervisor-4.4-amd64
3. git clone devstack && configure it to use Xen
LIBVIRT_TYPE=xen
4. ./stack.sh
5. Fix Bugs!!

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Bugs
2 Xen related bug in Nova
1 Xen related bug in Libvirt
Stability issues with libvirt 1.2.2-0ubuntu13.1.8 under stress

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Bugs
2 Xen related bug in Nova
1 Xen related bug in Libvirt
Stability issues with libvirt 1.2.2-0ubuntu13.1.8 under stress
FIXED!

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Bugs
2 Xen related bug in Nova
1 Xen related bug in Libvirt
Stability issues with libvirt 1.2.2-0ubuntu13.1.8 under stress
FIXED!

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Latest Update
2 patches under review for Nova
1 patch upstream in Libvirt
 everything works out of the box!
Using the latest OpenStack and libvirt trees
 Tempest runs and *all* tests pass!

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Tuning OpenStack and Xen
• 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

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More information
www.xenproject.org
wiki.xenproject.org
wiki.xenproject.org/wiki/Tuning_Xen_for_Performance
wiki.xenproject.org/wiki/OpenStack
http://lists.xenproject.org/mailman/listinfo/xen-devel

21. Demo

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Questions?

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WORK BETTER. LIVE BETTER.