I noticed when running an Alpine based virtual machine with Consul DNS forwarding set up, that sometimes the machine couldn’t resolve *.consul domains, but not in a consistent manner. Inspecting the logs looked like the request was being made and responded to successfully, but the result was being ignored. After a lot of googling and frustration, I was able to track down that it’s down to a difference (or optimisation) in musl libc, which glibc doesn’t do....

I use Vagrant when testing new machines and experimenting locally with clusters, and since moving (mostly) to Linux, I have been using the LibVirt Plugin to create the virtual machines. Not only is it significantly faster than Hyper-V was on windows, but it also means I don’t need to use Oracle products, so it’s win-win really. The only configuration challenge I have had with it is setting up VM hostname resolution, and as I forget how to do it each time, I figured I should write about it....

I will update this post as I learn more (both positive and negative), and is here to be linked to when people ask me why I don’t like Kubernetes, and why I would pick Nomad in most situations if I chose to use an orchestrator at all. TLDR: I don’t like complexity, and Kubernetes has more complexity than benefits. Operational Complexity Operating Nomad is very straight forward. There are very few moving parts, so the number of things which can go wrong is significantly reduced....

So we want to set up a Vault instance, and have it’s storage be a TLS based Consul cluster. The problem is that the Consul cluster needs Vault to create the certificates for TLS, which is quite the catch-22. Luckily for us, quite easy to solve: Start a temporary Vault instance as an intermediate ca Launch Consul cluster, using Vault to generate certificates Destroy temporary Vault instance Start a permanent Vault instance, with Consul as the store Reprovision the Consul cluster with certificates from the new Vault instance There is a repository on Github with all the scripts used, and a few more details on some options....

I was recently using my Hashibox for a test, and I noticed the DNS resolution didn’t seem to work. This was a bit worrying, as I have written about how to do DNS resolution with Consul forwarding in Ubuntu, and apparently something is wrong with how I do it. Interestingly, the Alpine version works fine, so it appears there is something not quite working with how I am configuring Systemd-resolved....

This post is going to go through how to set up a Consul cluster to communicate over TLS. I will be using Vagrant to create three machines locally, which will form my cluster, and in the provisioning step will use Vault to generate the certificates needed. How to securely communicate with Vault to get the TLS certificates is out of scope for this post. Host Configuration Unless you already have Vault running somewhere on your network, or have another mechanism to generate TLS certificates for each machine, you’ll need to start and configure Vault on the Host machine....

Often when developing or testing some code, I need (or want) to use SSL, and one of the easiest ways to do that is to use Vault. However, it gets pretty annoying having to generate a new CA for each project, and import the CA cert into windows (less painful in Linux, but still annoying), especially as I forget which cert is in use, and accidentally clean up the wrong ones....

This is a text version of a short talk (affectionately known as a “Coffee Bag”) I gave at work this week, on Architecture Design Records. You can see the slides here, but there isn’t a recording available, unfortunately. It should be noted; these are not to replace full architecture diagrams; you should definitely still write C4 Models to cover the overall architecture. ADRs are for the details, such as serializer formats, convention-over-configuration details, number precisions for timings, or which metrics library is used and why....

I wanted to implement canary routing for some HTTP services deployed via Nomad the other day, but rather than having the traffic split by weighting to the containers, I wanted to direct the traffic based on a header. My first choice of tech was to use Fabio, but it only supports routing by URL prefix, and additionally with a route weight. While I was at JustDevOps in Poland, I heard about another router/loadbalancer which worked in a similar way to Fabio: Traefik....

One of the points I make in my Feature Toggles talk is that you shouldn’t be querying a toggle’s status all over your codebase. Ideally, each toggle gets checked in as few places as possible - preferably only one place. The advantage of doing this is that very little of your codebase needs to be coupled to the toggles (either the toggle itself or the library/system for managing toggles itself)....