Originally published 2015-09-02 on the UoB Unix blog The eduroam wireless network has a reliance on a database for the authorization and accounting parts of AAA (authentication, authorization and accounting – are you who you say you are, what access are you allowed, and what did you do while connected). When we started dabbling with database-backed AAA in 2007 […]Read more "Rethinking database architecture"
Originally published 2016-11-21 on the UoB Unix blog Several times, senior management have asked Team Wireless to provide an uptime figure for eduroam. While we do have an awful lot of monitoring of systems and services, it has never been possible to give a single uptime figure because it needs some detailed knowledge to make sense of […]Read more "Service availability monitoring with Nagios and BPI"
The Ford Mondeo mk5 (from 2015 onwards) has a number of useful features that are disabled in the factory but can be unlocked using free software and a USB cable, without any special knowledge. Here’s how. You will need a compatible ELM327 cable. There are loads on eBay but it can’t be just any – […]Read more "Unlocking features in your mk5 Mondeo with FORScan"
Originally published 2016-08-01 on the UoB Unix blog We make extensive use of SELinux on all our systems. We manage SELinux config and policy with the jfryman/selinux Puppet module, which means we store SELinux policies in plain text .te format – the same format that audit2allow generates them in. One of our SELinux policies that covers permissions for NRPE is a large file. When we generate […]Read more "Merging SELinux policies"
There are many benefits to Kubernetes but what’s not discussed so often is how to migrate your services from their legacy hosting to their new home in Kubernetes. Specifically, I’m looking at the case where you have a single server or a single public IP address and you want to run your services on that […]Read more "Fronting legacy services with Kubernetes"
The M5 motorway is notorious for accidents in the summer holidays, and 2019 seems to be the worst year than anyone can remember – it seems like there is a crash on the M5 every other day. I’ve done a little light research to put some numbers to the congestion.Read more "M5 traffic incidents"
Since the 1960s, Canon SLRs have had their power switch confusingly labelled as A and L. This has persisted through many different generations of camera and confused beginners through the ages. But what do the letters A and L stand for? Why not use On and Off, or a red dot and a white dot, […]Read more "The mystery of the Canon A/L switch"
It was recently announced that a new building is being constructed next to my office. It’s not any old building – it’s going to be a 26-storey tower, the tallest in Bristol! Working on the second-top floor of an adjacent office block, this is a great opportunity to get a birds’ eye view of the construction […]Read more "Time lapse photography"
For the last article I wrote, a comparison of Canon 50mm lenses, I needed some way of photographing and displaying these lenses so they wouldn’t roll away. I decided to make some very simple lens stands out of scrap wood. Here’s how.Read more "Making simple lens display stands out of wood"
Anyone interested in photography will surely have heard of the “nifty fifty” – the 50mm standard SLR lens. Almost every single SLR manufacturer had a 50mm lens with and f/1.7, f/1.8 or f/2.0 aperture that was sold as the “kit lens”, and Canon was no exception. These days, “kit lens” has become a dirty word […]Read more "Canon 50mm f/1.8: the evolution of an icon"