Configuring the physical infrastructure

Before the installation of OpenStack can begin, the physical network infrastructure must be configured to support the networks needed for an operational cloud. In a production environment, this will likely include a dedicated management VLAN used for server management and API traffic, a VLAN dedicated to overlay network traffic, and one or more VLANs that will be used for provider and VLAN-based project networks. Each of these networks can be configured on separate interfaces, or they can be collapsed onto a single interface if desired.

The reference architecture for OpenStack Networking defines at least four distinct types of traffic that will be seen on the network:

• Management
• API
• External
• Guest

These traffic types are often categorized as control plane or data plane, depending on the purpose, and are terms used in networking to describe the purpose of the traffic. In this case, control plane traffic is used to describe traffic related to management, API, and other non-VM related traffic. Data plane traffic, on the other hand, represents traffic generated by, or directed to, virtual machine instances.

Although I have taken the liberty of splitting out the network traffic onto dedicated interfaces in this book, it is not necessary to do so to create an operational OpenStack cloud. In fact, many administrators and distributions choose to collapse multiple traffic types onto single or bonded interfaces using VLAN tagging. Depending on the chosen deployment model, the administrator may spread networking services across multiple nodes or collapse them onto a single node. The security requirements of the enterprise deploying the cloud will often dictate how the cloud is built. The various network and service configurations will be discussed in the upcoming sections.