Book Image

Learning OpenStack Networking (Neutron)

By : James Denton
Book Image

Learning OpenStack Networking (Neutron)

By: James Denton

Overview of this book

OpenStack Neutron is an OpenStack component that provides networking as a service for other OpenStack services to architect networks and create virtual machines through its API. This API lets you define network connectivity in order to leverage network capabilities to cloud deployments. Through this practical book, you will build a strong foundational knowledge of Neutron, and will architect and build an OpenStack cloud using advanced networking features. We start with an introduction to OpenStack Neutron and its various components, including virtual switching, routing, FWaaS, VPNaaS, and LBaaS. You’ll also get hands-on by installing OpenStack and Neutron and its components, and use agents and plugins to orchestrate network connectivity and build a virtual switching infrastructure. Moving on, you’ll get to grips with the HA routing capabilities utilizing VRRP and distributed virtual routers in Neutron. You’ll also discover load balancing fundamentals, including the difference between nodes, pools, pool members, and virtual IPs. You’ll discover the purpose of security groups and learn how to apply the security concept to your cloud/tenant/instance. Finally, you' ll configure virtual private networks that will allow you to avoid the use of SNAT and floating IPs when connecting to remote networks.
Table of Contents (21 chapters)
Learning OpenStack Networking (Neutron) Second Edition
About the Author
About the Reviewers

Exploring how instances get their addresses

When a network is created and DHCP is enabled on a subnet within the network, the network is scheduled to one or more DHCP agents in the environment. A dnsmasq process is spawned in a network namespace that corresponds to the network. If a dnsmasq process already exists for the network and a new subnet is added, the existing process is updated to support the additional subnet.


When DHCP is not enabled on a subnet, a dnsmasq process is not spawned. An IP address is still associated with the Neutron port that corresponds to the interface within the instance, however. Without DHCP services, it is up to the user to manually configure the IP address on the interface within the guest operating system through a console session.

Most instances rely on DHCP to obtain their associated IP addresses. DHCP goes through the following stages:

  • A DHCP client sends a DHCPDISCOVER broadcast packet that requests IP information from a DHCP server.

  • A DHCP server responds...