简单几招助您加速 ARM 容器应用开发和测试流程

时间 2019-11-24

标签简单助您加速 arm 容器应用开发测试流程繁體版

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随着5G时代的临近，低延迟网络、AI硬件算力提高、和智能化应用快速发展，一个万物智联的时代必将到来。咱们须要将智能决策、实时处理能力从云延展到边缘和IoT设备端。阿里云容器服务推出了边缘容器，支持云-边-端应用一体协同。在IoT和边缘计算场景，咱们不但须要支持X86芯片也要提供对ARM架构芯片的支持。此外随着国产ARM CPU的快速发展，也须要咱们在产品测提供ARM版本的容器产品支持。本文将介绍一些简单的技术来加速 ARM 容器应用的开发和测试流程。python

X86环境构建ARM架构Docker镜像

今年4月24日，Docker公司与ARM公司宣布合做伙伴计划，为Docker的工具优化面向ARM平台的开发者体验。Docker开发者能够在x86桌面端为ARM设备构建容器镜像，并可将容器应用部署至云端、边缘以及物联网设备。整个容器构建流程很是简单，无需任何交叉编译步骤。linux

Docker Desktop 是 macOS 和 Windows平台的容器开发环境。Docker会借助宿主机操做系统的虚拟化技术，如Windows的Hyper-V和 macOS的HyperKit，来运行Docker开发环境。在最新的Docker版本中，LinuxKit做为面向容器的操做系统，增长了QEMU模拟器，能够支持ARM架构CPU。如今能够支持 arm/v6, arm/v7 和 arm64 架构应用。架构图以下：git

首先安装最新edge版本的 Docker Desktop，Docker Engine版本须要大于 19.03。github

在Docker Desktop中，选择 "Preference..." > "Command Line" > "Enable experimental features" 开启实验特性。docker

Docker新增长了 docker buildx 命令npm

$ docker buildx --help

Usage:  docker buildx COMMAND

Build with BuildKit

Management Commands:
  imagetools  Commands to work on images in registry

Commands:
  bake        Build from a file
  build       Start a build
  create      Create a new builder instance
  inspect     Inspect current builder instance
  ls          List builder instances
  rm          Remove a builder instance
  stop        Stop builder instance
  use         Set the current builder instance
  version     Show buildx version information

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

咱们能够查看一下当前builder的状态bootstrap

$ docker buildx ls
NAME/NODE DRIVER/ENDPOINT STATUS  PLATFORMS
default * docker
  default default         running linux/amd64, linux/arm64, linux/arm/v7, linux/arm/v6

建立一个 mybuilder 实例，设置为默认构建器并激活ARM构建能力浏览器

$ docker buildx create --name mybuilder
mybuilder
$ docker buildx use mybuilder
$ docker buildx inspect --bootstrap
[+] Building 20.2s (1/1) FINISHED
 => [internal] booting buildkit                                           20.2s
 => => pulling image moby/buildkit:master                                 19.6s
 => => creating container buildx_buildkit_mybuilder0                       0.6s
Name:   mybuilder
Driver: docker-container
Nodes:
Name:      mybuilder0
Endpoint:  unix:///var/run/docker.sock
Status:    running
Platforms: linux/amd64, linux/arm64, linux/arm/v7, linux/arm/v6

从Github获取测试应用网络

$ git clone https://github.com/adamparco/helloworld
$ cd helloworld

在Docker Hub建立一个测试Repository架构

自从Docker registry v2.3和Docker 1.10开始，Docker经过支持新的image Media 类型 manifest list 实现了Multi-architecture Docker镜像功能，支持在一个镜像中同时包含多种CPU体系架构的镜像层。

为测试应用构建多CPU体系架构镜像，包含x86, ARM 64和ARM v7支持，并推送到 Docker Hub

$ docker buildx build --platform linux/amd64,linux/arm64,linux/arm/v7 -t denverdino/multiarch --push .
  .
[+] Building 26.1s (31/31) FINISHED
...
 => [linux/arm64 internal] load metadata for docker.io/library/python:3.7-alpine                                                                                                                                                         2.9s
 => [linux/arm/v7 internal] load metadata for docker.io/library/python:3.7-alpine                                                                                                                                                        3.2s
 => [linux/amd64 internal] load metadata for docker.io/library/python:3.7-alpine                                                                                                                                                         2.9s
...
 => exporting to image                                                                                                                                                                                                                  22.8s
 => => exporting layers                                                                                                                                                                                                                  1.0s
 => => exporting manifest sha256:f8739d2eb9f1b043e5d44e962c79d353261a257ffa6c8332b762b5d811d54c1a                                                                                                                                        0.0s
 => => exporting config sha256:528fc30a95957bf3c6c1bb4ea77793a2a484c0c5b87f3efad6bbc9dbc2df6a90                                                                                                                                          0.0s
 => => exporting manifest sha256:b52df7ab39acbe3ebb8b5d9e6a8069b9c916f1811b81aa84dd3b9dd9b4304536                                                                                                                                        0.0s
 => => exporting config sha256:9712542f20d1dd16c7332f664432a1b37c6254fefe7d4cb7806b74997467da07                                                                                                                                          0.0s
 => => exporting manifest sha256:698969718e9a316003a7fb4c2fe26216c95672e3e92372d25b01a6db5295e9e7                                                                                                                                        0.0s
 => => exporting config sha256:f636eaa8cec74fa574f99318cddd01b37a9e7c21708f94e11ae6575b34ca18f7                                                                                                                                          0.0s
 => => exporting manifest list sha256:3da22eea857f889ade3c85a2d41ed17db727385f78096e3dcf74ae039f164281                                                                                                                                   0.0s
 => => pushing layers                                                                                                                                                                                                                   18.3s
 => => pushing manifest for docker.io/denverdino/multiarch:latest

咱们能够在Docker Hub查看镜像信息

在Mac上面执行构建出来的镜像，

$ docker run -p5000:5000 denverdino/multiarch
 * Serving Flask app "hello" (lazy loading)
 * Environment: production
   WARNING: Do not use the development server in a production environment.
   Use a production WSGI server instead.
 * Debug mode: off
 * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)

访问 http://0.0.0.0:5000/ 能够看到当前CPU架构为 x86_64

登陆到树莓派（Raspbian基于ARMv7），执行以下命令，运行一样的容器镜像

pi@raspberrypi:~ $ docker run -p5000:5000 denverdino/multiarch
* Serving Flask app "hello" (lazy loading)
* Environment: production
  WARNING: Do not use the development server in a production environment.
  Use a production WSGI server instead.
* Debug mode: off
* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)

打开浏览器访问 raspberrypi:5000 ，能够看到当前CPU架构为 armv7l

X86环境执行ARM架构Docker镜像

咱们首先构建一个ARMv7版本的镜像

docker buildx build --platform linux/arm/v7 -t denverdino/multiarch:armv7 --push .
[+] Building 67.9s (13/13) FINISHED
...
 => => pushing layers                                                                                                                                                                                                                    8.5s
 => => pushing manifest for docker.io/denverdino/multiarch:armv7

Linux 内核中 binfmt_misc 容许注册一个“解释器”，在运行可执行文件的时候调用自定义解释器。Linux 4.8 版本在 binfmt_misc 中增长了 F flag 使内核能够在配置时加载解释器而非在运行时 Lazy load，经过这个方法咱们能够利用一个容器来注册和运行ARM指令集的解释器。

$ docker run --rm --privileged npmccallum/qemu-register

在Mac上运行以下命令，无需任何修改就能够启动一个ARM镜像

$ docker run -p5000:5000 denverdino/multiarch:armv7
 * Serving Flask app "hello" (lazy loading)
 * Environment: production
   WARNING: Do not use the development server in a production environment.
   Use a production WSGI server instead.
 * Debug mode: off
 * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)

访问 http://0.0.0.0:5000/ ，能够看到当前CPU架构变成为 armv7l。意外不意外？惊不惊喜？:-)

总结

利用容器、操做系统和虚拟化技术，咱们能够轻松在X86平台构建和测试ARM应用，简化了多CPU体系架构应用的支持。

原文连接本文为云栖社区原创内容，未经容许不得转载。