CERN is the home of the Large Hadron Collider (LHC), a 27km circular proton accelerator generating tens of petabytes of new data every year. Data is stored and processed using a large amount of resources totaling over 250.000 cores and 1000s of storage servers, managed by OpenStack.
Networking is a critical part of our infrastructure and arguably the hardest to evolve. Given the size of CERN’s infrastructure, its flat network is partitioned in segments each representing a separate broadcast domain and potentially offering different levels of service. This fragmentation improves scalability and reduces the impact of misbehaving systems in the datacentre to individual segments. On the other hand, having multiple broadcast domains means features like floating and virtual IPs are much harder to offer.
We will tell the story of OpenStack Networking at CERN. First integration with Nova Network, the migration to Neutron and how we're adding SDN in our infrastructure.
In this presentation we go through the story of OpenStack and networking at CERN. We will show how we first integrated OpenStack and Nova Network and the restrictions this first setup implied.
Next we cover the migration to OpenStack Neutron with some added functionality, the Neutron extensions we added to express the network fragmentation (and how it later got into the core of Neutron), and how we tackled its scalability challenges. We will provide details on how Nova Cells were used to reduce the impact of introducing the new service as well as migrating older resources from Nova Network to Neutron.
Finally we will cover the next (and ongoing) step in our OpenStack networking path, with the inclusion of software defined networking and overlay networks for greater flexibility and advanced functionality.
