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Since I work a lot with clustered VMs, I’ve ended up spending a lot of time trying to figure out how DNS lookups work. I applied ‘fixes’ to my problems from StackOverflow without really understanding why they work (or don’t work) for some time. Eventually I got fed up with this and decided to figure out how it all hangs together. I couldn’t find a complete guide for this anywhere online, and talki

After 6 years, I removed Docker from all my home servers. apt purge -y docker-ce Why? This was triggered by a recurring incident I faced where the Docker daemon was using 100% CPU on multiple cores that made the host effectively unusable. This had happened a few times before, and was likely due to a script that had got out of hand starting up too many containers. I’d never really got to the bottom

Continuing in the series of posts about lesser-known bash features, here I take you through seven variables that bash makes available that you may not have known about. 1) PROMPT_COMMAND You might already know that you can manipulate your prompt to show all sorts of useful information, but what fewer people know is that you can run a shell command every time your prompt is displayed. In fact many

Then… If, like me, you’re over 40 and work in IT, you’ll probably remember a time when everyone used Windows, and a small but growing proportion of people were wasting their lives compiling Linux in their spare time. The Windows users would look on, baffled: ‘Why would you do that, when Windows has everything you need, is supported, and is so easy to use?!’ Answers to this question varied. Some li

Here it is (base64-encoded): H4sICIa2A1sCA2IA7Vrrbts2FFYL7M9+7QUGGNyfDYhtkuJFFLAhWZOhBYJmaLMOWBAEFC+xVlkyJLpYEBjdY+0l+k6jfGvqtkEWp2qD8TMg8vAqnsNzDg9lQhhmEjHDhY4zgWJBBUQJ5ZnCGAubMUQMyhJqoRRMJxYbo7Q2CedYxlQO/myqMroeEEHICIngApspxohEKI4h5DHmGEUQQw7jqAejDjBtnKz9q2w7zubi7gkugazVKHdGuWltQArkWDMCdoCqSpufg/QSPK4aV8pxW+nL96uxzMu39G+NqRe5PeekGj13Oi9BamXRmCtl1dS9X2jqel147C7W+aOJKd8dZ04dlcqsSw7KVyA9Ab/uHT/+cTh

I work at a very ‘locked-down’ enterprise, where direct access to Docker is effectively verboten. This, fundamentally, is because access to Docker is effectively giving users root. From Docker’s own pages: First of all, only trusted users should be allowed to control your Docker daemon. Most home users get permissions in their account (at least in Linux) by adding themselves to the docker group, w

If you’re managing a complex git codebase with multiple developers, then you may well be using a tool like GitHub or BitBucket to delve into the history and figure out branch and merge issues. These GUIs are great for providing a nice user interface for managing pull requests and simple histories and the like, but when the workflow SHTF there’s no substitute for using git log and its relatively li

If you haven’t seen it, this is a very accurate and smart Downfall satire on Docker’s ecosystem, technology, and culture. It’s so good that I thought it would be instructive to annotate it so that the state of the art and some technical details of Docker could be better explained. Tweet me @ianmiell if you spot a problem or want to suggest an improvement. Annotated script Henchman: We pushed the i

This post is based on material from Docker in Practice, available on Manning’s Early Access Program. Get 39% off with the code: 39miell We’re writing a book on Docker that’s focussed on its practical aspects. Why? James Turnbull’s “The Docker Book” is a great introduction to Docker for those that want a good grounding in the basics of Docker. And other books like Docker in Action are in the pipe t