Build Time: Especially when your builds are integrated in a Continuous Integration pipeline (CI), reducing the build time can significantly reduce your apps' development cost.Consistency: If you are consistent designing your images, they are easier to maintain and you will reduce the time spent when developing new images.These are the main areas of improvement I will cover in this guide: Reuse cached layers that do not change in the image rebuild process to improve the build time. What is the Docker build cache?Įvery time you build a Docker image, each build step is cached. The layers can also be referred to as 'build steps'. What is a Docker layer?Įach layer in a Docker context represents an instruction included in a Docker image's Dockerfile. The process of building a Docker image from a Dockerfile is known as a Docker build.įind detailed information in the Dockerfile reference.

Currently, more than a million Dockerfiles are on GitHub. What is a Dockerfile?Ī Dockerfile is just a blueprint that contains the instructions to build a Docker image. It is represented as a list of instructions (known as layers) in a filesystem. What is a Docker image?Ī Docker image is a template that allows you to instantiate running containers. Let's review some of the basic concepts before you start to put them into practice. This guide assumes you are familiar with Docker and its build environment.

Refreshing basic concepts about Docker images and Dockerfiles To do that, I have provided you with a GitHub repository that contains all the files you need, to follow the tips and tricks shown in this post. Then, I will walk you through some practical examples, to improve the build time, the size, and the security of a Docker image. First, I will briefly explain some basic concepts that you need to refresh before examining specific cases.

In this tutorial, I will go over these lessons learned, describing some of the best practices and common pitfalls that you are likely to encounter when developing Dockerfiles, by applying them on practical examples. As part of the team which maintains a container catalog with more than 130 apps, I have worked on adapting the containers and their Dockerfiles to meet the community requirements. Since Bitnami published its first Docker container in 2015, the techniques for writing Dockerfiles have significantly evolved.

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