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/regis...
- Manifest命令：https://docs.docker.com/engin...
- Registry：https://github.com/docker/dis...
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 。