Vincent Untz discusses running multiple hypervisors in an OpenStack cloud. OpenStack supports various hypervisors like KVM, Xen, Hyper-V, and VMware through different drivers. Running multiple hypervisors allows using each hypervisor's strengths and migrating workloads. It presents challenges for integration with OpenStack components and feature parity. SUSE Cloud provides tools to deploy and manage multiple hypervisors in a single OpenStack cloud.

1. Running multiple hypervisors
in your OpenStack Cloud
Vincent Untz <vuntz@suse.com>
Project Manager, SUSE
OpenStack in Action 4 ! - Paris – 5th December 2013

2. OpenStack & Hypervisor
• “OpenStack is a global collaboration of developers and cloud computing
technologists producing the ubiquitous open source cloud computing platform
for public and private clouds.”
http://www.openstack.org/
• “A hypervisor or virtual machine monitor (VMM) is a piece of computer
software, firmware or hardware that creates and runs virtual machines.”
http://en.wikipedia.org/wiki/Hypervisor
OpenStack in Action 4 ! - Paris – 5th December 2013

4. OpenStack: “Ubiquitous”, “Open”
• Perceived as the “Linux of the cloud”
• Hypervisor-agnostic approach
– Support as many hypervisors as possible
– Support running multiple hypervisors in the same cloud
• Impact on the non-compute components of the project
OpenStack in Action 4 ! - Paris – 5th December 2013

5. Hypervisor History in OpenStack
• Ancient times: libvirt (KVM, QEMU)
• Early days (2010/2011):
– libvirt (KVM, QEMU, UML, Xen), XenAPI, first Hyper-V driver
– LXC (through libvirt) and “VMware”
• 2012:
– Hyper-V dropped... and coming back
– Baremetal
– PowerVM
• 2013:
– “VMware” rewritten, using vCenter
– Docker
– Baremetal moving to Ironic
OpenStack in Action 4 ! - Paris – 5th December 2013

6. Hypervisor Trends in OpenStack
• Hypervisor requests:
– 2011: Xen was quite popular
– 2012: KVM moved relatively fast as the “default”
– 2013: People starting to ask for “VMware” and Hyper-V
– Starting to hear about containers
• Multi-hypervisor support:
– Most deployments used a single hypervisor
– Requirements for enterprise clearly show need for multiple hypervisors in the
same cloud
OpenStack in Action 4 ! - Paris – 5th December 2013

7. Summary of Available Hypervisors
• libvirt: KVM, Xen, LXC, QEMU, UML
• XenAPI
• “VMware”
• Hyper-V
• Docker
• PowerVM
• Baremetal
OpenStack in Action 4 ! - Paris – 5th December 2013

9. Ensuring High Quality
• Unit tests and functional tests executed for each code
change
– Obviously requires a huge amount of resources!
– Difficult for some hypervisors; require external system
• In the future, drivers not receiving enough attention will be
deprecated
OpenStack in Action 4 ! - Paris – 5th December 2013

10. Why use a specific hypervisor?
• Better internal knowledge of technology
• Appliances requiring a specific platform
• ISV-provided application certified for specific hypervisor
OpenStack in Action 4 ! - Paris – 5th December 2013

11. Why use a specific hypervisor?
• KVM/Xen:
– Very good support from Linux vendors
• XenAPI:
– Desktop virtualization
• VMware:
– Often an already existing infrastructure
– Ability to use vCenter for advanced features
• Hyper-V:
– Windows on Windows
– Single license covers the hypervisor and the workloads
• LXC/Docker:
– Lightweight
OpenStack in Action 4 ! - Paris – 5th December 2013

12. Why use more than one hypervisor?
• Getting the best of each hypervisor
• Using OpenStack as a common interface for different technologies
– Including self-service features
• Slowly migrate workloads from existing infrastructure to cloud
• Mixed cloud with (for instance) Linux on Linux, Windows on Windows,
legacy application on VMware
• Optimized costs
OpenStack in Action 4 ! - Paris – 5th December 2013

13. Challenges of running multiple
hypervisors
• Integration with other OpenStack components:
– Networking
– Block Storage
– Metering
• Unified interface, but not exact same feature set
OpenStack in Action 4 ! - Paris – 5th December 2013

15. Challenges of running multiple
hypervisors
• Integration with other OpenStack components:
– Networking
– Block Storage
– Metering
• Unified interface, but not exact same feature set
• Scheduling images to the right compute node
• Full support from vendor (and its partners)?
OpenStack in Action 4 ! - Paris – 5th December 2013

16. The end user point of view
• No easy way to do all this from the OpenStack Dashboard
• Choosing hypervisor while uploading an image:
– hypervisor_type property:
glance image-create --property hypervisor_type=kvm […]
– vm_mode property. For Xen:
vm_mode=xen, vm_mode=hvm
• Choosing hypervisor while booting an instance:
– Picking a specific host for the instance:
nova boot --availability_zone zone:host […]
OpenStack in Action 4 ! - Paris – 5th December 2013

17. The end user point of view
• Alternative: using host aggregates
– Group compute nodes in a host aggregate with a specific property
– Create favors using this property
– Downside: only doable by administrators
OpenStack in Action 4 ! - Paris – 5th December 2013

18. vCenter (“VMware”)
• Compute host communicates with vCenter
– Enables the use of features such as vMotion, High Availability,
Dynamic Resource Scheduling (DRS)
• A cluster of ESX hosts is seen as one hypervisor entity
– vCenter uses DRS to schedule inside the cluster
• One compute host can manage several clusters
OpenStack in Action 4 ! - Paris – 5th December 2013

19. OpenStack in Action 4 ! - Paris – 5th December 2013

20. vCenter (“VMware”)
• Limitations:
– Shared storage required for ESX hosts
– Images must use the VMDK format
– Security groups only work with the NSX neutron plug-in
– vSphere 5.0 and earlier require some manual configuration
• VMware (and others) working in the community to improve support for
this driver
– VMDK driver for Cinder to have volumes on vCenter managed data stores
OpenStack in Action 4 ! - Paris – 5th December 2013

21. Hyper-V
• Integration architecture with OpenStack is rather simple: a
Windows node will be a compute node
• Manual setup of Windows as compute node is not trivial,
though. Solutions:
– Cloudbase provides an installer
– SUSE Cloud automates this step
OpenStack in Action 4 ! - Paris – 5th December 2013

22. Hyper-V
• Windows Server 2012 recommended
– Hyper-V Server can be used for free
• Limitations:
– Images must use the VHD/VHDX format
– Does not work with all neutron plug-ins
• Development is going well. Changes in Havana include:
– Support for Windows Server 2012 R2
– Support of VHDX format
– Ephemeral storage
– Dynamic memory
– Integration with Ceilometer
OpenStack in Action 4 ! - Paris – 5th December 2013

23. Hyper-V
• Session from Alessandro Pilotti (Cloudbase) at 15:20 in the
business track:
“OpenStack, Hyper-V and Windows”
OpenStack in Action 4 ! - Paris – 5th December 2013

24. What about deployment?
• “Simply” a matter of configuring all compute nodes the
way you want
• Need to be careful about networking technology used
– ML2 plug-in in Havana does help
• Most deployment tools are targeting the one hypervisor
use case, though
OpenStack in Action 4 ! - Paris – 5th December 2013

25. Concrete example: using KVM
• In nova.conf of compute node:
compute_driver=libvirt.LibvirtDriver
libvirt_type=kvm
• Of course, there are many other options
• Each hypervisor generally has a set of specific options
OpenStack in Action 4 ! - Paris – 5th December 2013

26. Multiple Hypervisors with
SUSE Cloud
• Support for:
– KVM
– Xen
– Hyper-V
• Tech preview for:
– VMware vCenter
• All in the same cloud!
• Install from baremetal for KVM, Xen and Hyper-V compute nodes
OpenStack in Action 4 ! - Paris – 5th December 2013

27. OpenStack in Action 4 ! - Paris – 5th December 2013

28. Thank you!
Vincent Untz <vuntz@suse.com>
OpenStack in Action 4 ! - Paris – 5th December 2013