The Quantum L3 router and floating IPs

This post shows how the Quantum L3 Agent uses the Linux IP stack to implement the Quantum L3 Routing and NAT API extensions. It explains in detail how external access with floating IP works and how it can be debugged.

Debugging Quantum DHCP and Open vSwitch

This post describes how Quantum DHCP in Grizzly works when using the Open vSwitch plugin. A basic understanding of the mechanism is needed to troubleshoot issues.

OpenStack Grizzly with Quantum multi-node auto-install script

This Ansible script installs OpenStack Grizzly onto three Vagrant/VirtualBox nodes using the OpenStack packages from the Ubuntu cloud archive. The install steps are in the readme.

Using the python-quantumclient

I was not able to find any doc except this, so I used the client source for clues on the functions/arguments and the API guide for the make-up of the request/response dictionaries.

This script creates a network (net1) and configures the external network. Then a router is created with its gateway is set to the external network and it is given an interface on net1. An instance is created with an nic connected to net1, and a floating IP is created and associated with the port the vm's nic is plugged into. Here is the CLI doing the same.

Automated OpenStack Folsom with Quantum install using Ansible/Vagrant/VirtualBox

This script (folsom branch) installs OpenStack Folsom with Quantum networking fully configured in about 10 minutes - once the prereqs are in place. The readme has the usage. It is written in Ansible which is easy to learn and quick to work with. It uses the OpenStack packages from the Ubuntu cloud archive and sets up this configuration:

Eventlet snippets

OpenStack services use the green threads model as described here. I found an excellent explanation of Eventlet in a video by Donovan Preston. I have typed in some of the snippets he uses here.

Paste config in OpenStack

If you are new to OpenStack you may be wondering what ini files like this are all about. OpenStack services (Nova, Glance, Quantum etc) use Paste Deployment to wire up middleware like authorisation, API extensions, request rate limiting etc. It helps to have a basic knowledge of this stuff for installing and troubleshooting. This post is a simple example based on this presentation. Here I have put the various parts in different modules.