This Post will give you an introduction to Docker BuildKit & Buildx

What is buildkit?

Buildkit is a project made by moby it’s working on top of docker to give you ability to have custom volumes while building images (caching, secret, etc.)

Using buildkit you cat easily cache package managers (even if you change packages), change network mode per-layer, secret files only for one layer, ssh keys (cloning a repo), or running one layer as privileged, and also faster than normal docker :)

What about buildx?

buildx makes buildkit even more powerful, it supports all syntaxes from buildkit it features:

  1. multiple types of builders (kubernetes [also buildkit got that option but this one is better], qemu/kvm[multi-arch builds], docker container, docker)

  2. custom layer cache exporting (registry with our custom name, or local)

  3. pushing image (and also cache [if set]) to registry after build


with the help of that you can have up to 6x faster builds (depends on conditions)

and I got better performance from buildx than kaniko

Enough, How to use them?

For Buildkit

You have two ways to activate it:

  1. setting DOCKER_BUILDKIT=1 as environment variable
  2. set this configuration in /etc/docker/daemon.json and restart docker daemon
    "buildkit": true

NOTE: You need active internet connection to get custom frontends and also docker 18.09 or higher

Sample Dockerfile to cache apt package manager

# syntax = docker/dockerfile:1.3
FROM debian
RUN rm -f /etc/apt/apt.conf.d/docker-clean; echo 'Binary::apt::APT::Keep-Downloaded-Packages "true";' > /etc/apt/apt.conf.d/keep-cache
RUN --mount=type=cache,target=/var/cache/apt --mount=type=cache,target=/var/lib/apt \
  apt update && apt-get --no-install-recommends install -y gcc

Specify syntax to get all features that we need checkout docker/dockerfile in dockerhub (like shebang in bash :])

checkout here to see more info about syntax

For Buildx

  1. if you are not using deb or rpm package get the latest release from Release page on github & put in into ~/.docker/cli-plugins/docker-buildx
  2. make it executable by running
chmod a+x ~/.docker/cli-plugins/docker-buildx

NOTE: is not supported only CE & EE

Full document for buildx is here there are tons of commands but syntax is as the same as Buildkit.

What I Love about these is the impact of speed of buildx & also a beautiful logging

Also Using k8s & docker-container builders you can monitor what is happening easily

thats it ;)