Recent Blog Posts

Adding strings to an array in Ansible

From time to time, I need to dynamically build a list of strings (or a list of other things) using Ansible's set_fact module.

Since set_fact is a module like any other, you can use a with_items loop to loop over an existing list, and pull out a value from that list to add to another list.

For example, today I needed to retrieve a list of all the AWS EC2 security groups in a region, then loop through them, building a list of all the security group names. Here's the playbook I used:

Use an ARG in Dockerfile FROM for dynamic image specification

Dockerfiles have been able to use ARGs to allow passing in parameters during a docker build using the CLI argument --build-arg for some time. But until recently (Docker's 17.05 release, to be precise), you weren't able to use an ARG to specify all or part of your Dockerfile's mandatory FROM command.

But since the pull request Allow ARG in FROM was merged, you can now specify an image / repository to use at runtime. This is great for flexibility, and as a concrete example, I used this feature to allow me to pull from a private Docker registry when building a Dockerfile in production, or to build from a local Docker image that was created as part of a CI/testing process inside Travis CI.

To use an ARG in your Dockerfile's FROM:

Mount a Raspberry Pi SD card on a Mac (read-only) with osxfuse and ext4fuse

So you're telling me I can read files from a Raspberry Pi microSD card?

For my Raspberry Pi Time-Lapse App, I find myself having to either copy hundreds (or thousands!) of 3+ MB image files, or a 1-2 GB video file from a Raspberry Pi Zero W to my Mac.

Copying over the WiFi network works, but it's extremely slow (usually topping out around 5 Mbps... which means it could take a couple hours to copy). So I decided to finally try to mount the Raspberry Pi's drive directly on my MacBook Pro (running macOS Sierra 10.12). This is normally a bit tricky, because the Raspberry Pi uses the Linux ext4 filesystem—which is not compatible with either macOS or Windows!

dockrun oneshot — quick local environments for testing infrastructure

Since I work among a ton of different Linux distros and environments in my day-to-day work, I have a lot of tooling set up that's mostly-OS-agnostic. I found myself in need of a quick barebones CentOS 7 VM to play around in or troubleshoot an issue. Or I needed to run Ubuntu 16.04 and Ubuntu 14.04 side by side and run the same command in each, checking for differences. Or I needed to bring up Fedora. Or Debian.

I used to use my Vagrant boxes for VirtualBox to boot a full VM, then vagrant ssh in. But that took at least 15-20 seconds—assuming I already had the box downloaded on my computer!

Drupal VM does Docker

Drupal VM on Docker Hub

Drupal VM has used Vagrant and (usually) VirtualBox to run Drupal infrastructure locally since its inception. But ever since Docker became 'the hot new thing' in infrastructure tooling, I've been asked when Drupal VM will convert to using Docker.

The answer to that question is a bit nuanced; Drupal VM has been using Docker to run its own integration tests for over a year (that's how I run tests on seven different OSes using Travis CI). And technically, Drupal VM's core components have always been able to run inside Docker containers (most of them use Docker-based integration tests as well).

But Docker usage was always an undocumented and unsupported feature of Drupal VM. But no longer—with 4.5.0, Drupal VM now supports Docker as an experimental alternative to Vagrant + VirtualBox, and you can use Drupal VM with Docker in one of two ways:

Call for Sessions is open for DrupalCamp St. Louis 2017 - come and speak!

DrupalCamp St. Louis logo - Fleur de Lis

DrupalCamp St. Louis 2017 will be held September 22-23, 2017, in St. Louis, Missouri. This will be our fourth year hosting a DrupalCamp, and we're one of the best camps for new presenters!

If you did something amazing with Drupal, if you're an aspiring themer, site builder, or developer, or if you are working on making the web a better place, we'd love for you to submit a session. Session submissions are due by August 1.

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