docker镜像

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多架构镜像

查看镜像的多架构信息

可以使用 docker manifest inspect $image 命令来查看，manifest为docker的体验特性，在Linux系统下开启，需要在本地创建 ~/.docker/config.json 文件，内容如下：

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{
    "experimental": "enabled"
}

最好的方式为开启docker daemon的特性，修改 /etc/docker/daemon.json 文件：

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{
  "experimental": true
}

例如执行 docker manifest inspect golang:alpine 可以看到golang 官方的docker镜像包含了多架构信息，每个架构下会对应一个sha256值。

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{
   "schemaVersion": 2,
   "mediaType": "application/vnd.docker.distribution.manifest.list.v2+json",
   "manifests": [
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1365,
         "digest": "sha256:725f8fd50191209a4c4a00def1d93c4193c4d0a1c2900139daf8f742480f3367",
         "platform": {
            "architecture": "amd64",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1365,
         "digest": "sha256:5adcff3a3e757841a6c7b07f1986b2a36cb0afaf47025e78bb17358eda2d541a",
         "platform": {
            "architecture": "arm",
            "os": "linux",
            "variant": "v6"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1365,
         "digest": "sha256:84a1e4174b934fbf8f1dfe9f7353a5be449096b6f2273d6af5a364ffd6bf8f15",
         "platform": {
            "architecture": "arm",
            "os": "linux",
            "variant": "v7"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1365,
         "digest": "sha256:86cfea5046e196f5061324c93f25ef05e1df58ba96721e0c0b42cc6e0cf22e49",
         "platform": {
            "architecture": "arm64",
            "os": "linux",
            "variant": "v8"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1365,
         "digest": "sha256:5ad072476cb8b51dddaf4142789f1528c7d48a3a0c31941a5ce21177c8e47259",
         "platform": {
            "architecture": "386",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1365,
         "digest": "sha256:fca6cbe2f1fb9095eac2669c0be58b482135f9cf7196d51ac7338ea3e7c556c7",
         "platform": {
            "architecture": "ppc64le",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1365,
         "digest": "sha256:3f7ac24ca4b3ce61b51439cb59b57a8151ba60bd73a0e33cc06020dda6b692cb",
         "platform": {
            "architecture": "s390x",
            "os": "linux"
         }
      }
   ]
}

gcr.io 可以在 console 上直接看到信息，比如: nginx镜像

多架构镜像的构建

可以使用docker buildx命令，比如 docker buildx build -t <image-name> --platform=linux/arm64,linux/amd64 . --push 可以同时构建出arm64和amd64的镜像。

查看镜像的构建历史

可以使用 docker history --no-trunc ${image} 来查看镜像的每层构建命令

通过代理拉取镜像

创建或者修改/etc/docker/daemon.json文件，文件内容如下：

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{
  "registry-mirrors": [
    "https://hub-mirror.c.163.com",
    "https://mirror.baidubce.com"
  ]
}

重启docker后通过docker info命令查看输出结果：

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$ docker info
 Registry Mirrors:
  https://hub-mirror.c.163.com/
  https://mirror.baidubce.com/
 Live Restore Enabled: false

参考资料