Docker Arm images

Docker Arm images with Depot

Building Docker images for Arm via docker build from a host architecture running an Intel chip is forced to use QEMU emulation to build Docker Arm images. It's also only possible to build multi-platform Docker images using emulation or running your own BuildKit builders.

Depot removes emulation altogether.

Depot is a remote Docker container build service that orchestrates optimized BuildKit builders on native CPUs for Intel (x86) and Arm (arm64).

When a Docker image build is routed to Depot either via depot build or docker build, we launch optimized builders for each architecture requested with a persistent layer cache attached to them. Each image builder, by default, has 16 CPUs and 32GB of memory. If you're on a startup or business plan, you can configure your builders to be larger, with up to 64 CPUs and 128 GB of memory. Each builder also has a fast NVMe SSD with at least 50GB for layer caching.

How to build Docker images for Arm CPUs like Apple Silicon or AWS Graviton

With depot build or docker build configured to use Depot, it automatically detects the architecture you're building for and routes the build to the appropriate builder.

So, if you're building a Docker image from a macOS device running Apple Silicon (M1, M2, M3, M4), there is nothing extra you need to do. We will detect the architecture and route the build to an Arm builder.

depot build .

If you're building a Docker image from an Intel machine, like a CI provider, you can specify --platform linux/arm64 to build a Docker Arm image.

docker build --platform linux/arm64 .

We have integration guides for most of the CI providers:

• Bitbucket Pipelines
• Buildkite
• CircleCI
• GitHub Actions
• GitLab CI
• Google Cloud Build
• Jenkins
• Travis CI

How to build multi-platform Docker images

With Depot, we can launch multiple builders in parallel to build multi-platform Docker images concurrently. To build a multi-platform Docker image for both Intel & Arm, we can specify --platform linux/amd64,linux/arm64 to depot build or docker build.

depot build --platform linux/amd64,linux/arm64 .

Loading a multi-platform Docker image via --load

If you want to load a multi-platform Docker image into your local Docker daemon, you will hit an error when using docker buildx build --load:

docker exporter does not currently support exporting manifest lists

This is because the default behavior of load does not support loading multi-platform Docker images. To get around this, you can use depot build --load instead where we have made load faster & more intelligent.

depot build --platform linux/amd64,linux/arm64 --load .