Versioning is one of the many hard problems when it comes to writing software. There is no one correct way to do it, and all have various tradeoffs. After reading keep a changelog, I was inspired to implement this into a couple of CLI tools that I am working on at the moment: Flagon (feature flags on the CLI, for CI usage), and Cas (Content Addressable Storage for Make), but I also wanted to solve my versioning and release process....

When migrating to a continuous delivery process, it is often the case that a QA team are worried about what their role is going to be, and how the changes will affect the quality of the software in question. While doing continuous delivery does change the QA process, when done well, it improves everyone’s lives and makes the software better quality. Are silver bullets incoming? Not quite, but we don’t have to make someone’s life worse to improve other people’s lives....

Recently we were having a debate about release processes, and I wrote that deployments are not always equal to releases. also deploy != release —Andy, baiting discussion in Slack This turned out to be somewhat controversial until we discussed what I specifically meant by deploy and release. As with all things, agreeing on definitions or understanding what someone means when they use a specific term is essential, so I thought I would write down a short blog post on it....

On several occasions when building complex projects, I have been tempted to set up Bazel to help speed up the build process; after all, it has a lot to offer: only building what has changed, caching built artifacts, and sharing that cache between machines for even more speed. TLDR We can use Make and a couple of short shell scripts to implement file content-based caching and read/write that cache to remote storage, such as S3....

I write a lot of blog posts which contain code snippets. Like most people, I have done this using a fenced codeblock in markdown which is fine for short blocks of code. The problem occours when I am embedding code from another repository; often there will be tweaks or bug fixes, and keeping the code in the blog post in sync with the code in the other repo is annoying and manual....

This is in response to the recent posts about the death of UML; while I think some parts of UML have fallen ill, the remaining parts are still alive, and useful to this day. TLDR Out of 14 types of diagram there are 3 that I use on a regular basis: Activity Diagram, State Machine Diagram, and Sequence Diagram. I think the Timing Diagram is borderline, but I can only think of a couple of occasions when it has been useful....

One of the reasons I prefer Pulumi over Terraform is the additional control I have over my processes due to the fact that it’s a programming language. For example, I have a CLI, that creates a cluster of machines for a user; the machines use IAM Authentication with Vault so that they can request certificates on boot. The trouble with this application is that it is slow; it takes 175 seconds on average to provision the machines, write the IAM information to Vault, and then re-run the cloud-init script on all the machines in the cluster (as when they first booted, the configuration hadn’t been written to Vault yet....

I recently encountered a behaviour in Nginx that I didn’t expect and caused a production outage in the process. While I would love to blame DNS for this, as it’s usually the cause of most network-related issues, in this case, the fault lies with Nginx. I was running a very simple Nginx proxy, relaying an internal service to the outside world. The internal service is behind an AWS ALB, and the Nginx configuration was proxying to the ALB’s FQDN:...

The Operator Pattern from Kubernetes is an excellent way of handling tasks in a cluster in an automated way, for example, provisioning applications, running backups, requesting certificates, and injecting chaos testing. As a Nomad user, I wanted to do something similar for my clusters, so I set about seeing how it would be possible. It turns out; it is much easier than I expected! While Nomad doesn’t support the idea of Custom Resource Definitions, we can achieve an operator by utilising a regular Nomad job and the nomad HTTP API....

An interesting question came up at work today: how do you tag your Docker images? In previous projects, I’ve always used a short git sha, or sometimes a semver, but with no great consistency. As luck would have it, I had pushed for a change in tagging format at a client not so long ago as the method we were using didn’t make a lot of sense and, worst of all, it was a manual process....