In my previous post I described how I transitioned myself into the container era by installing the OpenShift v3 in DigitalOcean and containerizing my applications. This post will describe how I moved from my previous blog engine to Hugo engine.

My previous blog engine was a hand-written Sinatra application that was just serving Markdown files. Everything else was just Javascript. While that seems pretty decent and minimal, in fact it is not. The Ruby Docker image is something around 430MB and while 90% of that is just centos:7, it is still ‘too much’. Also the ruby itself is pretty memory hungry and DigitalOcean is not really about having extra memory to spare.

I was looking into something more minimal, preferably Go based static web site generator, so I can just copy the static binary into a minimal Docker image and have really small image with my blog in the end.

Then I found hugo. It is fast and flexible static site generator, written by spf13, a guy who is behind popular cobra and many other successfull Go projects.

Hugo is very simple to use tool, you can check the tutorial, and what it basically does is converting the Markdown files into static HTML pages. It also comes with countless themes you can start from. As a bonus, it also comes with very fast HTTP server, which is built-in into its binary.

Now, how to configure OpenShift to automatically build and deploy my blog? First, I have to create Github repository and upload my content there.

Then I need to craft the Source-To-Image builder image that will take the source (content above) and produce the Docker image that will contain hugo server and my content.

The source for the image is here. Some points about this image:

  • It uses FROM golang:alpine which is a new official Go builder image based on minimal Alpine Linux.
  • It compiles hugo from the source, giving me the latest master version.
  • I remove all unnecesary packages after the build to keep the final image small.
  • Image log to a pipe which is streamed to the standard output, so I can watch the logs in container log.
  • The assemble script compiles the blog content to verify that nothing is broken.
  • You can change the theme by setting HUGO_THEME variable.
  • And you should change HUGO_BASE_URL as well ;-)

To create my blog, I run the following command:

$ oc new-app mfojtik/hugo~

That’s it! The resulting image is ~200 MB. It also consume almost no memory, so I can scale it up on DigitalOcean without adding extra node to get more memory.

I also configured the Github hooks to automatically trigger the build of this blog when I push to the master branch. Which is how I publishing this article. Jut by pushing it to github. And you can see the result here :-)