Buildkit with Docker Compose

By Syed Wahaj

Docker Compose is a tool for defining and running multi-container Docker applications. It uses YAML files to configure the services and containers that make up an application. BuildKit is a new build engine that is included with Docker since version 18.09. It provides faster and more efficient builds compared to the traditional Docker build engine.

By default, Docker Compose uses the traditional Docker build engine, but it’s possible to enable BuildKit by configuring Docker Compose. In this article, we’ll show how to enable BuildKit in Docker Compose.

Prerequisites

Before we begin, ensure that you have the following prerequisites:

Docker Compose installed
Docker version 18.09 or higher

Step 1: Create a Docker Compose File

First, we need to create a Docker Compose file. This file defines the services that make up our application. We will create a simple example that builds a web application using BuildKit.

Create a new directory for your project and change into it:

$ mkdir myproject$ cd myproject

Create a new file called docker-compose.yml and add the following contents:

version: '3'services:web:build:context: .dockerfile: Dockerfileimage: my-web-app

This file defines a service called web. The service uses the Dockerfile in the current directory to build an image. The resulting image is tagged with the name my-web-app.

Step 2: Enable BuildKit

To enable BuildKit in Docker Compose, set the DOCKER_BUILDKIT environment variable to 1.

You can set the environment variable in your shell before running Docker Compose:

$ export DOCKER_BUILDKIT=1$ docker-compose build

Or you can set the environment variable in your Docker Compose file:

version: '3'services:web:build:context: .dockerfile: Dockerfileextra_hosts:- "example.com:host_ip"network_mode: "host"image: my-web-appenvironment:DOCKER_BUILDKIT: 1

In this example, we set the DOCKER_BUILDKIT environment variable to 1 in the web service.

Step 3: Build and Run the Application

Now that we have enabled BuildKit, we can build and run our application.

To build the image, run:

$ docker-compose build

Docker Compose will use BuildKit to build the image.

To run the application, run:

$ docker-compose up

This will start the web service and any other services defined in your Docker Compose file.

Conclusion

BuildKit is a new build engine that provides faster and more efficient builds compared to the traditional Docker build engine. In this article, we showed how to enable BuildKit in Docker Compose. By enabling BuildKit, you can speed up your Docker builds and take advantage of the latest Docker features.