Author: doozer
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Understanding TUN TAP Interfaces
As I mentioned in the previous article Understanding Bridges, Linux and most other operating systems have the ability to create virtual interfaces which are usually called TUN/TAP devices. This article will discuss those devices with particular focus on how they are used in OpenStack.
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Understanding Bridges
In this article I’ll discuss network bridges and where they are commonly used (spoiler: they aren’t any more). Mainly though I want to discuss how bridges are used in an OpenStack set up as building a personal cloud is my final aim. Hardware network bridges aren’t as common as they once were as switches have…
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Understanding VLANs
The aim of this article is to explain VLANs to someone who has a reasonable understand of how a computer network works. Recently I’ve been reading up on OpenStack as I’d like to put together a small personal cloud for a project I’m working on. So far so easy but the one aspect that I’ve been…
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WobblyStack – Reading List
I had to read a lot before I could get to the point where I felt I could write a script that installed OpenStack for me. The links below are a selection of articles that I found useful. This is the complete list of things I read as I didn’t start compiling the list before…
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A Quick Introduction to Open vSwitch
In a previous article I discussed bridges and showed how the Linux utilities bridge-utils and iproute2 could be used to create virtual bridges within a system. This is great for simple set up but when deploying a cloud environment a bit more functionality is required and that’s where Open vSwitch comes in.
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Installing VirtualBox Additons on Ubuntu Server
I have a number of Ubuntu 14.04 virtual machines installed under VirtualBox running on Windows 8.1 and occasionally I find it useful to have the VirtualBox additions installed. Unfortunately for me the documented process doesn’t seem to work. Whenever I mount the ISO image using Devices –> Insert Guest Additions CD Image… I find that…
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Udacity Computer Networking Course Notes
I’ve just started the Udacity course on Computer Networking and I’ve hit a few bumps along the way so I thought I’d document them here for others to find.
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Mininet Waiting for Network Configuration
I recently started taking the Udacity course on Computer Networking and while it looks like a good course it suffers from the same problem all the Udacity courses seem to suffer from: really badly put together examples and quizzes. It’s a shame because the material itself is generally of a really high quality. The problem I…
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Using PuTTY for Key-Based SSH Login
If you are on Windows and need to “shell” into a Linux machine then PuTTY is the tool of choice. For password based logins it’s as simple as entering the IP address or name of the machine you want to connect to but for key based logins things get a little more complicated. This guide…
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WobblyStack – A Single Node OpenStack Install
For a couple of years now I’ve run a small VMWare virtualization system for my business. Broadly speaking it’s gone well and been fairly uneventful. The only panic came when I transitioned from the free to the small business version of the software – I installed more memory than was allowed in the free version,…
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ManagedBeanCreationException – What’s gone wrong now!
I recently failed to inject a managed bean into another bean that I was writing and for the life of me I couldn’t see what I’d done wrong. As is often the case it’s the little things that trip us up and in this case I was so used to doing it I couldn’t see…