Visualizing Neutron Networking with GraphViz

Mon 23 December 2013 by Lars Kellogg-Stedman Tags openstack neutron networking

I've put together a few tools to help gather information about your Neutron and network configuration and visualize it in different ways. All of these tools are available as part of my neutron-diag repository on GitHub.

In this post I'm going to look at a tool that will help you visualize the connectivity of network devices on your system.

read more

Quantum in Too Much Detail

Thu 14 November 2013 by Lars Kellogg-Stedman Tags openstack quantum networking

I originally posted this article on the RDO website.

The players

This document describes the architecture that results from a particular OpenStack configuration, specifically:

  • Quantum networking using GRE tunnels;
  • A dedicated network controller;
  • A single instance running on a compute host

Much of the document will be relevant to other configurations, but details will vary based on your choice of layer 2 connectivity, number of running instances, and so forth.

The examples in this document were generated on a system with Quantum networking but will generally match what you see under Neutron as well, if you replace quantum by neutron in names. The OVS flow rules under Neutron are somewhat more complex and I will cover those in another post.

read more

Why does the Neutron documentation recommend three interfaces?

Mon 28 October 2013 by Lars Kellogg-Stedman Tags openstack neutron networking

The documentation for configuring Neutron recommends that a network controller has three physical interfaces:

Before you start, set up a machine to be a dedicated network node. Dedicated network nodes should have the following NICs: the management NIC (called MGMT_INTERFACE), the data NIC (called DATA_INTERFACE), and the external NIC (called EXTERNAL_INTERFACE).

People occasionally ask, "why three interfaces? What if I only have two?", so I wanted to provide an extended answer that might help people understand what the interfaces are for and what trade-offs are involved in using fewer interfaces.

read more

Waiting for networking using PowerShell

Sun 04 November 2012 by Lars Kellogg-Stedman Tags powershell networking windows

I've recently been exploring the world of Windows scripting, and I ran into a small problem: I was running a script at system startup, and the script was running before the network interface (which was using DHCP) was configured.

There are a number of common solutions proposed to this problem …

read more

Chasing OpenStack idle connection timeouts

Mon 30 July 2012 by Lars Kellogg-Stedman Tags openstack networking

The original problem

I've recently spent some time working on an OpenStack deployment. I ran into a problem in which the compute service would frequently stop communicating with the AMQP message broker (qpidd).

In order to gather some data on the problem, I ran the following simple test:

  • Wait n …
read more