The Nectar Research Cloud is built using the OpenStack Open Source Cloud Computing Software (link) and benefits from a strong maturation of the OpenStack software suite via its 6 monthly release cycle. The benefits include improved features, new services, and improved stability and reliability. Federation wide (i.e. at all 8 nodes and at Core Services) we have just finished, as of March 2017, migrating from the Liberty release to the Mitaka release (OpenStack 6 monthly releases are given names in alphabetical order).
Operationally it is not practical or even possible to jump all OpenStack components, across all 8 nodes in the federation, simultaneously from one release to a new release. The upgrade process sees the Research Cloud in a Chimera state most of the time - with various components at two or more different release levels. Also, OpenStack is deployed in combination with other software which also have dependencies and release schedules that further complicate our work - software such as the base Operating Systems (Ubuntu), networking software (MidoNet), management tools (puppet, libvirt etc.).
An analogy could be that it is like doing maintenance on an aircraft (engines etc) while in flight. Our goal is to keep it in the air without passengers (users) being notably affected or in many cases even aware that the work is being done.
Priority and final order of deployment of upgrades of individual OpenStack components depends on end user feature demand (LBaaS, updated and new API services etc.) and experience garnered at other OpenStack installations world wide.
Broadly, our plans for upgrades to OpenStack on the Nectar Research Cloud are:
Q1 Finalise upgrade to Mitaka release (most installed components at Mitaka release)
Q1 Commence upgrade to Newton release
Q2 Commence preparation/planning for Ocata release
Q3 Finalise upgrade to Newton release (most installed components at Newton release)
Q4 Commence upgrade to Ocata release
Q1 Commence preparation/planning for Pike release
Q1 Finalise upgrade to Ocata release (most installed components at Ocata release)
Our success in upgrading the Nectar Research cloud is due to the coordinated and dedicated approach of the technical staff at the eight (8) nodes and at Core Services.