For my first real post of my new blog, let’s talk about multi-stage docker builds. This blog is built with the aid of just such a build. A multi-stage docker build gives you the ability to build multiple containers. In the case of my build, it helps me build a single end-product that’s uncluttered by extra build configuration and tooling.

Why multi-stage?

Docker holds a place in the modern development pipeline for deployed applications similar to the role the classic Makefile has in building packaged applications. (There’s a reason the Dockerfile and Makefile use a similar nomenclature after all.) However, when building a deployed application, you often need to perform build tasks that create clutter. For example, if you’re building a C program, you’ll like need to install the build tools (sudo apt-get install build-essential) and then when you run make you get all those intermediate .o files needed for linking, and maybe you need to install Perl or Python to help run some of the glue code, etc.