Multi-Architecture镜像制作指南已到，请查收！

摘要：使用Multi-Architecture镜像，可以让docker根据系统架构去拉取对应的镜像，服务的部署脚本等可以在不同架构的系统间使用相同的配置，减化服务配置，提高了服务在不同系统架构间的一致性。

背景

由于Kubernetes集群支持amd64和arm64架构的系统，容器部署时两种类型的节点都可能被集群调度到；所以容器在打包推送到镜像仓库时需要考虑支持多架构，防止调度到不支持的架构节点导致运行失败。

简介

Docker register: v2.3.0开始支持Multi-Architecture镜像
Docker CLI

v1.11开始支持Multi-Architecture镜像拉取
v18.03开始支持Multi-Architecture镜像制作

参考资料：

- Manifest标准：https://docs.docker.com/registry/spec/manifest-v2-1/
- Manifest命令：https://docs.docker.com/engine/reference/commandline/manifest/
- Registry：https://github.com/docker/distribution/releases/tag/v2.3.0

制作说明

虽然Multi-Architecture标准很早就有，但是官方的Docker CLI直到v18.03版本才开始支持Multi-Architecture镜像的制作；或者可以考虑使用第三方工具，参考：构建多CPU架构支持的Docker镜像

后续Multi-Architecture镜像的制作使用Docker v18.09版本进行说明。

设置Docker

Docker使用manifest命令来设置MANIFEST_LIST从而支持Multi-Architecture。到Docker v18.09版本为止，manifest命令还是实验性的，所以要配置Docker使能实验性功能。

Docker daemon

修改配置文件/etc/docker/daemon.json，添加配置"experimental": true：

$ sudo cat /etc/docker/daemon.json

[sudo] password for zhangsan:

{

    "data-root": "/home/common/docker",

    "experimental": true,               <- 使能docker daemon实验性功能

    "storage-driver": "overlay2",

    "log-driver": "json-file",

    "log-opts": {

        "max-file": "10",

        "max-size": "100m"

    },

    "insecure-registries": [

        "docker-hub.***.com"

    ]

}

Docker Cli

修改当前用户home目录的配置文件~/.docker/config.json，添加配置"experimental": "enabled"：

$ cat ~/.docker/config.json

{

    "experimental": "enabled",          <- 使能docker cli实验性功能

        "proxies":

        {

            "default":

            {

                "httpProxy": "http://127.0.0.1:3128",

                "httpsProxy": "http://127.0.0.1:3128",

                "ftpProxy": "http://127.0.0.1:3128"

            }

        }

}

验证配置

重启docker服务，手工运行docker manifest，出现如下信息说明配置成功：

$ docker manifest

Usage:  docker manifest COMMAND

 Manage Docker image manifests and manifest lists

 Commands:

  annotate    Add additional information to a local image manifest

  create      Create a local manifest list for annotating and pushing to a registry

  inspect     Display an image manifest, or manifest list

  push        Push a manifest list to a repository

Run 'docker manifest COMMAND --help' for more information on a command.

镜像打包

示例程序stop是一个go程序，启动后暂停不做任何操作，编译到amd64和arm64平台，在amd64平台分别运行如下：

$ ll -hR

.:

total 8.0K

drwxrwxr-x 2 zhangsan zhangsan 4.0K Jun  3 17:21 amd64

drwxrwxr-x 2 zhangsan zhangsan 4.0K Jun  3 17:21 arm64

./amd64:

total 240K

-rw-rw-r-- 1 zhangsan zhangsan   51 Jun  3 17:21 Dockerfile

-rwxrwxr-x 1 zhangsan zhangsan 235K Jul 19  2014 stop

./arm64:

total 656K

-rw-rw-r-- 1 zhangsan zhangsan   51 Jun  3 17:21 Dockerfile

-rwxr-xr-x 1 zhangsan zhangsan 651K May 22 14:38 stop

$ amd64/stop

^C%

$ arm64/stop

zsh: exec format error: arm64/stop

使用相同的Dockerfile：

$ cat Dockerfile

FROM scratch

COPY stop /stop

ENTRYPOINT ["/stop"]

amd64版本

$ cd amd64

$ ls

Dockerfile  stop

# 使用tag标注平台信息。

$ docker build -t docker-hub.***.com/zhangsan/stop:1.0-amd64 .

Sending build context to Docker daemon  242.7kB

Step 1/3 : FROM scratch

 --->

Step 2/3 : COPY stop /stop

 ---> ffb0d366bb8c

Step 3/3 : ENTRYPOINT ["/stop"]

 ---> Running in 715d1fbcf450

Removing intermediate container 715d1fbcf450

 ---> 0584fe60ca3d

Successfully built 0584fe60ca3d

Successfully tagged docker-hub.***.com/zhangsan/stop:1.0-amd64

$ docker images | grep stop

REPOSITORY                                        TAG                 IMAGE ID            CREATED             SIZE

docker-hub.***.com/zhangsan/stop        1.0-amd64           0584fe60ca3d        3 seconds ago       240kB

$ docker push docker-hub.***.com/zhangsan/stop:1.0-amd64

The push refers to repository [docker-hub.***.com/zhangsan/stop]

9e352dcc98ab: Pushed

1.0-amd64: digest: sha256:e5b6263b7e45840f139f1bf40b774294712c95df1b43d41598b736f07110341f size: 526

# 可以用manifest的子命令inspect查看镜像的manifest信息，由于是私有仓库，需要使用--insecure参数。

$ docker manifest inspect -v --insecure docker-hub.***.com/zhangsan/stop:1.0-amd64

{

        "Ref": "docker-hub.***.com/zhangsan/stop:1.0-amd64",

        "Descriptor": {

                "mediaType": "application/vnd.docker.distribution.manifest.v2+json",

                "digest": "sha256:e5b6263b7e45840f139f1bf40b774294712c95df1b43d41598b736f07110341f",

                "size": 526,

                "platform": {

                        "architecture": "amd64",

                        "os": "linux"

                }

        },

        "SchemaV2Manifest": {

                "schemaVersion": 2,

                "mediaType": "application/vnd.docker.distribution.manifest.v2+json",

                "config": {

                        "mediaType": "application/vnd.docker.container.image.v1+json",

                        "size": 1489,

                        "digest": "sha256:0584fe60ca3dbff4c746d376855e89b72b022a4198373b3c8d4c41b97b8b4faf"

                },

                "layers": [

                        {

                                "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",

                                "size": 71322,

                                "digest": "sha256:7797d3b3ba41f7abc6a914250f793cf2d69a3e7c0bcc787a596eab4836554552"

                        }

                ]

        }

}

arm64版本

$ cd arm64

$ ls

Dockerfile  stop

$ docker build -t docker-hub.***.com/zhangsan/stop:1.0-arm64 .

Sending build context to Docker daemon  669.2kB

Step 1/3 : FROM scratch

 --->

Step 2/3 : COPY stop /stop

 ---> e02dd9cc9ffa

Step 3/3 : ENTRYPOINT ["/stop"]

 ---> Running in 9b574680691a

Removing intermediate container 9b574680691a

 ---> 1fc97e49b088

Successfully built 1fc97e49b088

Successfully tagged docker-hub.***.com/zhangsan/stop:1.0-arm64

$ docker images | grep stop

docker-hub.***.com/zhangsan/stop        1.0-arm64           1fc97e49b088        8 seconds ago       666kB

docker-hub.***.com/zhangsan/stop        1.0-amd64           0584fe60ca3d        3 minutes ago       240kB

$ docker push docker-hub.***.com/zhangsan/stop:1.0-arm64

The push refers to repository [docker-hub.***.com/zhangsan/stop]

a0c07ccfc4ae: Pushed

1.0-arm64: digest: sha256:089798dc96fcc3d2bf4da3ec4243adcc2507d2ae0c5ba77c5582af626702b3d6 size: 527

# 由于打包镜像的机器是amd64架构，所以arm64的应用镜像中architecture为amd64，后面可以修改，或者直接在arm64机器上打包。

$ docker manifest inspect -v --insecure docker-hub.***.com/zhangsan/stop:1.0-arm64

{

        "Ref": "docker-hub.***.com/zhangsan/stop:1.0-arm64",

        "Descriptor": {

                "mediaType": "application/vnd.docker.distribution.manifest.v2+json",

                "digest": "sha256:089798dc96fcc3d2bf4da3ec4243adcc2507d2ae0c5ba77c5582af626702b3d6",

                "size": 527,

                "platform": {

                        "architecture": "amd64",

                        "os": "linux"

                }

        },

        "SchemaV2Manifest": {

                "schemaVersion": 2,

                "mediaType": "application/vnd.docker.distribution.manifest.v2+json",

                "config": {

                        "mediaType": "application/vnd.docker.container.image.v1+json",

                        "size": 1488,

                        "digest": "sha256:1fc97e49b0883f59e1e894404785ea1867b9e557d55bdac92f2da09c92b659e7"

                },

                "layers": [

                        {

                                "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",

                                "size": 318698,

                                "digest": "sha256:4397808817371da0348eb097ca181996165a9836d629aa1fb97b0d3824ffe2e2"

                        }

                ]

        }

}

验证镜像

$ docker images | grep stop

docker-hub.***.com/zhangsan/stop        1.0-arm64           1fc97e49b088        21 hours ago        666kB

docker-hub.***.com/zhangsan/stop        1.0-amd64           0584fe60ca3d        21 hours ago        240kB

$ docker run docker-hub.***.com/zhangsan/stop:1.0-amd64

^C%

$ docker run docker-hub.***.com/zhangsan/stop:1.0-arm64

standard_init_linux.go:207: exec user process caused "exec format error"

创建MANIFEST_LIST

创建一个MANIFEST_LIST引用之前两个不同平台的镜像。

$ docker manifest inspect -v --insecure docker-hub.***.com/zhangsan/stop:1.0

no such manifest: docker-hub.***.com/zhangsan/stop:1.0

$ docker manifest create --insecure docker-hub.***.com/zhangsan/stop:1.0 docker-hub.***.com/zhangsan/stop:1.0-amd64 docker-hub.***.com/zhangsan/stop:1.0-arm64

Created manifest list docker-hub.***.com/zhangsan/stop:1.0

$ docker manifest inspect -v --insecure docker-hub.***.com/zhangsan/stop:1.0

[

        {

                "Ref": "docker-hub.***.com/zhangsan/stop:1.0-amd64",

                "Descriptor": {

                        "mediaType": "application/vnd.docker.distribution.manifest.v2+json",

                        "digest": "sha256:e5b6263b7e45840f139f1bf40b774294712c95df1b43d41598b736f07110341f",

                        "size": 526,

                        "platform": {

                                "architecture": "amd64",

                                "os": "linux"

                        }

                },

                "SchemaV2Manifest": {

                        "schemaVersion": 2,

                        "mediaType": "application/vnd.docker.distribution.manifest.v2+json",

                        "config": {

                                "mediaType": "application/vnd.docker.container.image.v1+json",

                                "size": 1489,

                                "digest": "sha256:0584fe60ca3dbff4c746d376855e89b72b022a4198373b3c8d4c41b97b8b4faf"

                        },

                        "layers": [

                                {

                                        "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",

                                        "size": 71322,

                                        "digest": "sha256:7797d3b3ba41f7abc6a914250f793cf2d69a3e7c0bcc787a596eab4836554552"

                                }

                        ]

                }

        },

        {

                "Ref": "docker-hub.***.com/zhangsan/stop:1.0-arm64",

                "Descriptor": {

                        "mediaType": "application/vnd.docker.distribution.manifest.v2+json",

                        "digest": "sha256:089798dc96fcc3d2bf4da3ec4243adcc2507d2ae0c5ba77c5582af626702b3d6",

                        "size": 527,

                        "platform": {

                                "architecture": "amd64",

                                "os": "linux"

                        }

                },

                "SchemaV2Manifest": {

                        "schemaVersion": 2,

                        "mediaType": "application/vnd.docker.distribution.manifest.v2+json",

                        "config": {

                                "mediaType": "application/vnd.docker.container.image.v1+json",

                                "size": 1488,

                                "digest": "sha256:1fc97e49b0883f59e1e894404785ea1867b9e557d55bdac92f2da09c92b659e7"

                        },

                        "layers": [

                                {

                                        "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",

                                        "size": 318698,

                                        "digest": "sha256:4397808817371da0348eb097ca181996165a9836d629aa1fb97b0d3824ffe2e2"

                                }

                        ]

                }

        }

]

修改MANIFEST_LIST

修改刚创建的MANIFEST_LIST，使镜像和架构对应。

$ docker manifest annotate docker-hub.***.com/zhangsan/stop:1.0 docker-hub.***.com/zhangsan/stop:1.0-arm64 --arch arm64

[

        {

                "Ref": "docker-hub.***.com/zhangsan/stop:1.0-amd64",

                "Descriptor": {

                        "mediaType": "application/vnd.docker.distribution.manifest.v2+json",

                        "digest": "sha256:e5b6263b7e45840f139f1bf40b774294712c95df1b43d41598b736f07110341f",

                        "size": 526,

                        "platform": {

                                "architecture": "amd64",

                                "os": "linux"

                        }

                },

                "SchemaV2Manifest": {

                        "schemaVersion": 2,

                        "mediaType": "application/vnd.docker.distribution.manifest.v2+json",

                        "config": {

                                "mediaType": "application/vnd.docker.container.image.v1+json",

                                "size": 1489,

                                "digest": "sha256:0584fe60ca3dbff4c746d376855e89b72b022a4198373b3c8d4c41b97b8b4faf"

                        },

                        "layers": [

                                {

                                        "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",

                                        "size": 71322,

                                        "digest": "sha256:7797d3b3ba41f7abc6a914250f793cf2d69a3e7c0bcc787a596eab4836554552"

                                }

                        ]

                }

        },

        {

                "Ref": "docker-hub.***.com/zhangsan/stop:1.0-arm64",

                "Descriptor": {

                        "mediaType": "application/vnd.docker.distribution.manifest.v2+json",

                        "digest": "sha256:089798dc96fcc3d2bf4da3ec4243adcc2507d2ae0c5ba77c5582af626702b3d6",

                        "size": 527,

                        "platform": {

                                "architecture": "arm64",

                                "os": "linux"

                        }

                },

                "SchemaV2Manifest": {

                        "schemaVersion": 2,

                        "mediaType": "application/vnd.docker.distribution.manifest.v2+json",

                        "config": {

                                "mediaType": "application/vnd.docker.container.image.v1+json",

                                "size": 1488,

                                "digest": "sha256:1fc97e49b0883f59e1e894404785ea1867b9e557d55bdac92f2da09c92b659e7"

                        },

                        "layers": [

                                {

                                        "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",

                                        "size": 318698,

                                        "digest": "sha256:4397808817371da0348eb097ca181996165a9836d629aa1fb97b0d3824ffe2e2"

                                }

                        ]

                }

        }

]

推送MANIFEST_LIST到镜像仓库

创建的MANIFEST_LIST会保存在本地目录~/.docker/manifests，在push时可以使用-p(--purge)参数删除本地数据：

$ ll -R ~/.docker/manifests

/home/zhangsan/.docker/manifests:

total 4

drwxr-xr-x 2 zhangsan zhangsan 4096 Jun  3 17:57 docker-hub.***.com_zhangsan_stop-1.0

/home/zhangsan/.docker/manifests/docker-hub.***.com_zhangsan_stop-1.0:

total 8

-rw-r--r-- 1 zhangsan zhangsan 733 Jun  3 17:57 docker-hub.***.com_zhangsan_stop-1.0-amd64

-rw-r--r-- 1 zhangsan zhangsan 734 Jun  3 18:01 docker-hub.***.com_zhangsan_stop-1.0-arm64

$ sudo docker manifest push -p --insecure docker-hub.***.com/zhangsan/stop:1.0

[sudo] password for zhangsan:

sha256:401767ef0864a65578bef86e3baed2e1e0be905d08d88b57cdeb299850400ece

验证

$ docker images | grep stop

docker-hub.***.com/zhangsan/stop        1.0-arm64           1fc97e49b088        16 hours ago        666kB

docker-hub.***.com/zhangsan/stop        1.0-amd64           0584fe60ca3d        16 hours ago        240kB

# 在amd64架构的系统下拉取不带架构信息的镜像

$ uname -a

Linux SZX1000514415 4.4.0-87-generic #110-Ubuntu SMP Tue Jul 18 12:55:35 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

$ docker pull docker-hub.***.com/zhangsan/stop:1.0

1.0: Pulling from zhangsan/stop

Digest: sha256:401767ef0864a65578bef86e3baed2e1e0be905d08d88b57cdeb299850400ece

Status: Downloaded newer image for docker-hub.***.com/zhangsan/stop:1.0

$ docker images | grep stop

docker-hub.***.com/zhangsan/stop        1.0-arm64           1fc97e49b088        16 hours ago        666kB

docker-hub.***.com/zhangsan/stop        1.0                 0584fe60ca3d        16 hours ago        240kB

docker-hub.***.com/zhangsan/stop        1.0-amd64           0584fe60ca3d        16 hours ago        240kB

# 可正常运行

$ docker run docker-hub.***.com/zhangsan/stop:1.0

^C%

# 在arm64架构的系统下拉取不带架构信息的镜像

[root@kwephicprc09532 ~]# uname -a

Linux kwephicprc09532 4.1.44-06.160.vhulk1711.1.1.aarch64 #1 SMP Tue Oct 16 18:45:06 UTC 2018 aarch64 aarch64 aarch64 GNU/Linux

[root@kwephicprc09532 ~]# docker images | grep stop

[root@kwephicprc09532 ~]# docker pull docker-hub.***.com/zhangsan/stop:1.0

1.0: Pulling from zhangsan/stop

439780881737: Pull complete

Digest: sha256:401767ef0864a65578bef86e3baed2e1e0be905d08d88b57cdeb299850400ece

Status: Downloaded newer image for docker-hub.***.com/zhangsan/stop:1.0

[root@kwephicprc09532 ~]# docker images | grep stop

docker-hub.***.com/zhangsan/stop                          1.0                 1fc97e49b088        16 hours ago        666.5 kB

# 可正常运行

[root@kwephicprc09532 ~]# docker run docker-hub.***.com/zhangsan/stop:1.0

^CShutting down, got signal: Interrupt

升级MANIFEST_LIST

后期升级MANIFEST_LIST方法与创建类似，如：docker-hub.***.com/zhangsan/stop:1.0-amd64镜像升级或docker-hub.***.com/zhangsan/stop:1.0这个MANIFEST_LIST要关联其它镜像时，都需要升级MANIFEST_LIST。需要注意几点：

manifest create时使用参数-a(--amend)
升级后没有关联到期望的镜像可以先手工删除本地保存的manifest再尝试

使用Multi-Architecture镜像的好处

使用Multi-Architecture镜像，可以让docker根据系统架构去拉取对应的镜像，服务的部署脚本等可以在不同架构的系统间使用相同的配置，减化服务配置，提高了服务在不同系统架构间的一致性。

本文分享自华为云社区《叮！快收好这份Multi-Architecture镜像制作指南》，原文作者：Thirteenmans 。

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