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 retrieve their metadata

In Chapter 3, Installing Neutron, we briefly covered the process instances accessing metadata over the network, through either a proxy in the router namespace or the DHCP namespace. The latter is described in the following section.

The DHCP namespace

Instances can access metadata at, followed by a URI that corresponds to the version of metadata, usually /latest. When an instance is connected to a network that does not utilize a Neutron router as the gateway, the instance must learn how to reach the metadata service. This can be accomplished in a few different ways, including:

  • Setting a route manually on the instance

  • Allowing DHCP to provide a route

When enable_isolated_metadata is set to true in the DHCP configuration file at /etc/neutron/dhcp_agent.ini, each DHCP namespace provides a proxy to the metadata service running on the controller node. The proxy service listens directly on port 80, as shown in the following figure...