What Every OpenStack Nova User Needs To Know


By Gary Hilson | March 18, 2015 | Cloud, OpenStack, Nova



The release of OpenStack Juno in October 2014 added a slew of new features to the Nova component that include networking capabilities, but as work continues on the next-generation Kilo release, experts say users can expect more advanced features in a component called Neutron with which Nova will coexist.openstack-cloud

Nova, the cloud-based fabric controller used to provide OpenStack infrastructure-as-a-service, originally was the sole networking piece within OpenStack. In 2011, however, the OpenStack Quantum project, renamed Neutron, was started as a dedicated effort within OpenStack to provide full Software Defined Networking (SDN) capabilities and as a possible replacement for Nova.

With OpenStack Juno, however, both Neutron and Nova have seen improvements in networking features. This includes support for multiple networks while gaining visibility into network information by way of new data hooks. Juno also improved Network Functions Virtualization (NFV) in Nova with new multiple interface support. Meanwhile, Nova is poised to get a slew of updates with Kilo, the next version of OpenStack, including some additional networking features.

As Michael Still, project team leader for OpenStack Compute project, outlines in this video, Nova is what allows users to build a virtual machine and provide access to it. But to do that, Still notes, it might have to orchestrate other systems, which is where Neutron could be used for configuration purposes. Ultimately, Nova is what provides access to compute resources, Still said, and ties in with other OpenStack projects. Nova is likely part of the majority of OpenStack deployments, he added.

Nova and Neutron together

According to Still, the recent Kilo summit in Paris provided a clear direction as to where Nova should go, including the need for big architectural improvements. One new feature already available is the ability to create sub-Novas, which are called cells. Version 2 of this feature already is underway, but not likely to be completed with Kilo. There also is a lot of interest in developing the scheduler. Another priority for Kilo is Nova-to-Neutron migration, which is close to reality. There is a plan, but it has yet to be implemented.   

Donna Scott, an analyst with Cambridge, Mass.-based Gartner Inc., said Neutron is stealing some of the attention from Nova right now because it is a newer project within OpenStack. It also provides more advanced networking capabilities that businesses are demanding, such as automated networking across multiple data centers and clouds.

“It’s the (business) requirements that are pushing Neutron,” she said. “You need something more sophisticated, and Neutron lays the groundwork for that.”

Scott expects that in terms of new capabilities, networking updates probably will be implemented in Neutron, and having a migration tool would be a good thing. For anyone who starts an OpenStack deployment today, they would use Nova and Neutron together.

Nova Remains at the Core

Andreas Olah, research analyst for servers with IDC European Systems and Infrastructure Solutions, also expects Nova and Neutron to continue to coexist. He said the research firm has not done any studies that contrast Nova with Neutron yet, but that Nova remains a core component for the compute service, with Neutron fulfilling networking, Swift providing object storage, and Cinder supporting block storage. All these major OpenStack components need to be linked together.

Olah said Nova is considered the most complex component of the OpenStack family, mainly due to its numerous processes and highly distributed nature. Nova controls the cloud computing fabric and, therefore, is at the core of the infrastructure service.

As Nova is to continue in parallel with Neutron, the focus will be on tighter integration, said Olah. OpenStack consists of many different independent modules, he added, and there still are challenges integrating Nova with other components such as Neutron. He noted the Juno release provided 342 new features and corrected more than 3,200 errors that were causing headaches for users of previous versions. NFV also is gaining importance in the community as the Nova Compute project provides advanced functionality, such as the Ironic bare metal-as-a-service feature.

Olah said users should follow a step-by-step approach for deploying less critical workloads on Nova/OpenStack, then extend to key business applications as the initial trial proves successful.

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