一、前言

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最近接了ARM架构的容器化项目,于是乎新的需求出现了,同一个服务需要构建对应CPU架构的镜像,先前人是单独用ARM的机器编译,但是不优雅且重复性劳动,维护起来累.

二、 探索buildx

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2.1 启动buildx

在 Docker 19.03+ 版本中可以使用 docker buildx build 命令使用 BuildKit 构建镜像

2.2 查看docker buildx是否已开启

低版本的docker默认是没有开启的,手动开启下,export DOCKER_CLI_EXPERIMENTAL=enabled

高版本的docker默认是开启buildx,如图

三、启用buildx

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3.1 指定buildx 构建器

由于 Docker 默认的 builder 实例不支持同时指定多个 --platform ，我们必须首先创建一个新的 builder 实例并切换到指定名称的 buildx 构建器

[root@iZj6c261538xjcb56g6iv4Z ~]# docker buildx create --name builder --use

3.2 构建多架构镜像

前提基础镜像支持多架构CPU,可以参考下参数文档 (opens new window),文章 (opens new window)

[root@iZj6c261538xjcb56g6iv4Z demo]# docker login registry.cn-hangzhou.aliyuncs.com

[root@iZj6c261538xjcb56g6iv4Z demo]# cat Dockerfile
FROM ubuntu:latest

# 设置时区
ENV TZ=Asia/Shanghai

WORKDIR /opt
RUN echo "${TZ}" > /etc/timezone \
    && ln -sf /usr/share/zoneinfo/${TZ} /etc/localtime \
    && apt-get update \
    && apt install -y --no-install-recommends --no-install-suggests tzdata build-essential libpcre3 libpcre3-dev libssl-dev zlib1g-dev libpcre2-dev curl gnupg2 ca-certificates lsb-release ubuntu-keyring

[root@iZj6c261538xjcb56g6iv4Z demo]# docker buildx build --platform=linux/arm64,linux/amd64 -t  registry.cn-hangzhou.aliyuncs.com/s-ops/demo:v1 . --push

3.3查看某个多架构镜像的信息

上面的图可以清晰的看到同时构建了ARM64和AMD64的镜像,可以使用 docker manifest inspect 查看相关信息

[root@iZj6c261538xjcb56g6iv4Z demo]# docker manifest inspect  registry.cn-hangzhou.aliyuncs.com/s-ops/demo:v1
{
   "schemaVersion": 2,
   "mediaType": "application/vnd.oci.image.index.v1+json",
   "manifests": [
      {
         "mediaType": "application/vnd.oci.image.manifest.v1+json",
         "size": 863,
         "digest": "sha256:d93ef783d103a776ab5cf32aa7da942aefec1863a22b6879ab3f7c452a658290",
         "platform": {
            "architecture": "arm64",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.oci.image.manifest.v1+json",
         "size": 863,
         "digest": "sha256:0dc9bfb5b8e23e445b1e854d5e626d3dcbf7bdb845c1b79aa6c67fc323ade86b",
         "platform": {
            "architecture": "amd64",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.oci.image.manifest.v1+json",
         "size": 566,
         "digest": "sha256:26f1b2d7d10d9222e2646bde1ff9df2dda7ede956a53d6454ae5aa6ee8d422a6",
         "platform": {
            "architecture": "unknown",
            "os": "unknown"
         }
      },
      {
         "mediaType": "application/vnd.oci.image.manifest.v1+json",
         "size": 566,
         "digest": "sha256:8e5e4fa92a2a2cdc3c1a7dd0346af19c597e3c286f16d7aff9473403df508faa",
         "platform": {
            "architecture": "unknown",
            "os": "unknown"
         }
      }
   ]
}