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RedHat OpenStack Networking

Course Description

RHELOSP4 - Built on OpenStack Havana
20140424 - Looking to upgrade to Juno within the next month or so

Not overly popular course to look into upgrading the course content.
People doing development and then verbal training to other groups is the main ways to distribute knowledge

OpenStack Platform Terminology

Neutron - Only reason for neutron is if you need to compute to various other compute hosts where other instances are running. Neutron will supply them with managing the connections between those tunnels.

You wouldn't even need neutron if you had a single isolated host with guests on it.

Rally is a benchmarking tool that will allow you to try to configure a network node with appropriate bandwidth.

Packstack Install

packstack is basically an automated install environment where you generate a bunch of answers to installation questions kind of like kickstart for openstack.

In Ubuntu similar functionality is done via JuJu

Install Packstack

yum install -y openstack-packstack

Generate answer files

packstack --gen-answer-file /root/answers.txt

Modify the answer file to your chosing and then use it to install openstack

packstack --answer-file /root/answers.txt

You can specify where you would like any of the nodes to exist in packstack by specifying IP addresses. You will need to be registered with a repo that has the associated packages required for the redhat installation though.

5-6 node limitation

Openstack Dashboard allowed hosts file


In the allowed hosts settings you can specify * to allow all hosts or else you will have to specify the FQDN in order to access or direct IP address.

Networking Overview

Find all of the namespaces associated
You will find a dhcp and a router namespace

ip netns

Run commands against the namespace

ip netns qrouter-xxx-xxx ip a

NetworkManager service is not supported by OpenStack and we need to make sure it is not installed or disabled.


Removing IP Addresses from interfaces

ip address flush dev $interface

Open vSwitch

To show mac-address table on openvswitch

ovs-appctl fdb/show br-int

Information on ovs


No knowledge of GRE or VXLAN on linux bridges (some say you can get this knowledge implemented in bridges by updating linux kernel)

Linux Bridging with Libvirt

Linux bridges can be created using libvirt and the configuration is stored/saved in libvirt configs rather than in /etc/sysconfig/network-scripts/

You can either create local bridges or you can change the forward mode to "route" and tie that to a particular interface of your choosing if you'd like to route traffic externally.

Otherwise all traffic will either be internal or NAT'ed.

You can also create DHCP pools inside of these virtual network bridges.

vim testbridge.xml
<bridge name="testbr0">
<forward mode="route">
<ip address="" netmask="">
<range end="" start="">


virsh net-define testbridge.xml
virsh net-autostart private
virsh net-start private
virsh net-list

Neutron Networking Overview

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