安装 buildx

如果需要构建多架构的 Docker 镜像，可以使用在 Docker 19.03 中引入的 buildx 命令：

docker buildx

如果出现下列错误，代表 buildx 还未安装：

docker: 'buildx' is not a docker command.
See 'docker --help'

为 Alpine Linux 安装 buildx：

apk add docker-cli-buildx

配置 buildx

安装 QEMU 模拟器：

docker run --privileged --rm tonistiigi/binfmt --install all

创建 builder 实例：

docker buildx create --use

构建 Docker 镜像

在当前目录创建 Dockerfile 文件，示例如下：

FROM busybox:uclibc
ARG TARGETARCH
RUN echo "I'm building for $TARGETARCH"

构建 amd64、arm、arm64 架构，arch 标签的镜像：

docker buildx build --platform amd64,arm,arm64 -t arch .

输出：

WARN[0000] No output specified for docker-container driver. Build result will only remain in the build cache. To push result image into registry use --push or to load image into docker use --load
[+] Building 13.8s (12/12) FINISHED
 => [internal] booting buildkit 5.3s
 => => pulling image moby/buildkit:buildx-stable-1 2.2s
 => => creating container buildx_buildkit_dazzling_noyce0 3.1s
 => [internal] load build definition from Dockerfile 0.0s
 => => transferring dockerfile: 112B 0.0s
 => [internal] load .dockerignore 0.0s
 => => transferring context: 2B 0.0s
 => [linux/amd64 internal] load metadata for docker.io/library/busybox:uclibc 6.4s
 => [linux/arm64 internal] load metadata for docker.io/library/busybox:uclibc 6.4s
 => [linux/arm/v7 internal] load metadata for docker.io/library/busybox:uclibc 6.4s
 => [linux/arm64 1/2] FROM docker.io/library/busybox:uclibc@sha256:133c96e963fb798875f6dd48df3fd6e5d474e28b6f90cebef4f49f5b416200db  0.2s
 => => resolve docker.io/library/busybox:uclibc@sha256:133c96e963fb798875f6dd48df3fd6e5d474e28b6f90cebef4f49f5b416200db 0.0s
 => => sha256:9836d7c303877b21ce6157ef5e9a05f8d57ce86e8a1dc672777f6bbdbce6e9e3 833.12kB / 833.12kB 1.3s
 => => extracting sha256:9836d7c303877b21ce6157ef5e9a05f8d57ce86e8a1dc672777f6bbdbce6e9e3 0.2s
 => [linux/amd64 1/2] FROM docker.io/library/busybox:uclibc@sha256:133c96e963fb798875f6dd48df3fd6e5d474e28b6f90cebef4f49f5b416200db 0.2s
 => => resolve docker.io/library/busybox:uclibc@sha256:133c96e963fb798875f6dd48df3fd6e5d474e28b6f90cebef4f49f5b416200db 0.0s
 => => sha256:4399114b4c59be45238d2958ccaef1fa50ac18f83d2c1bb585e15a4af273b31f 778.68kB / 778.68kB 1.5s
 => => extracting sha256:4399114b4c59be45238d2958ccaef1fa50ac18f83d2c1bb585e15a4af273b31f 0.2s
 => [linux/arm/v7 1/2] FROM docker.io/library/busybox:uclibc@sha256:133c96e963fb798875f6dd48df3fd6e5d474e28b6f90cebef4f49f5b416200db 0.1s
 => => resolve docker.io/library/busybox:uclibc@sha256:133c96e963fb798875f6dd48df3fd6e5d474e28b6f90cebef4f49f5b416200db 0.0s
 => => sha256:385e4e16fa93807eb4867a8f553c32d6eb1f0275822b84a047342bb42e7cba66 729.12kB / 729.12kB 1.2s
 => => extracting sha256:385e4e16fa93807eb4867a8f553c32d6eb1f0275822b84a047342bb42e7cba66 0.1s
 => [linux/arm/v7 2/2] RUN echo "I'm building for arm" 0.3s
 => [linux/arm64 2/2] RUN echo "I'm building for arm64" 0.3s
 => [linux/amd64 2/2] RUN echo "I'm building for amd64" 0.2s

添加 --push 选项以将 Docker 镜像推送到 Docker Hub：

docker buildx build --push --platform amd64,arm,arm64 -t arch .

添加 --load 选项以将 Docker 镜像保存到本地（此选项仅支持一次构建 1 种架构）：

docker buildx build --load --platform amd64 -t arch .

参考：