Docker Buildx 构建多系统镜像

Docker Buildx 构建多系统镜像

由于开发调试编译需要，需要编译amd64、aarch64、arm64等不同平台指令二进制；为了方便使用者，编译多系统平台架构

以golang简单demo为例：

package main

import (
	"net/http"
	"os"
	"time"

	"github.com/prometheus/client_golang/prometheus/promhttp"
)

func main() {
	mux := http.NewServeMux()

	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("this is muti arch demo: GOARCH:" + os.Getenv("GOARCH")))
	})

	mux.Handle("/metrics", promhttp.Handler())

	s := &http.Server{
		Addr:           ":8080",
		Handler:        mux,
		ReadTimeout:    time.Second * 5,
		WriteTimeout:   time.Second * 5,
		MaxHeaderBytes: 1 << 20, // 1048576; 1MiB
	}
	s.ListenAndServe()
}

# Builder
FROM dongjiang1989/alpine:golang-1.18.8-alpine3.15 as builder

RUN mkdir -p /go/src/server

WORKDIR /go//src/server/

COPY main.go main.go
COPY vendor/  vendor/
COPY go.sum go.sum
COPY go.mod go.mod

RUN export GOPATH=/go/src
RUN export GO111MODULE=off

RUN  go build -a -ldflags "-linkmode external -extldflags -static" -o /demo-server main.go

# Server
FROM dongjiang1989/alpine:golang-1.18.8-alpine3.15

EXPOSE 8080

COPY --from=builder /demo-server /demo-server

ENTRYPOINT ["/demo-server"]

多平台架构需要使用docker buildx version

查看docker是否支持多架构编译：

dongjiang@MacBook Pro:buildx $ docker buildx create --use --name muti-builder --driver docker-container --buildkitd-flags --allow-insecure-entitlement security.insecure --allow-insecure-entitlement network.host
muti-builder

dongjiang@MacBook Pro:buildx $ docker buildx ls
NAME/NODE       DRIVER/ENDPOINT  STATUS   BUILDKIT PLATFORMS
muti-builder *  docker-container                   
  muti-builder0 desktop-linux    inactive          
default         docker                             
  default       default          running  20.10.21 linux/arm64, linux/amd64, linux/riscv64, linux/ppc64le, linux/s390x, linux/386, linux/arm/v7, linux/arm/v6
desktop-linux   docker                             
  desktop-linux desktop-linux    running  20.10.21 linux/arm64, linux/amd64, linux/riscv64, linux/ppc64le, linux/s390x, linux/386, linux/arm/v7, linux/arm/v6

编译多架构镜像

dongjiang@MacBook Pro:buildx $ docker buildx build -t dongjiang1989/muti-arch-demo-server:latest --platform=linux/arm64,linux/amd64,linux/riscv64,linux/ppc64le,linux/s390x,linux/386,linux/arm/v7,linux/arm/v6 .
[+] Building 0.7s (10/10) FINISHED                                                                                                                                   
 => [internal] load build definition from Dockerfile                                                                                                            0.0s
 => => transferring dockerfile: 540B                                                                                                                            0.0s
 => [internal] load .dockerignore                                                                                                                               0.0s
 => => transferring context: 2B                                                                                                                                 0.0s
 => CANCELED [linux/arm/v6 internal] load metadata for docker.io/dongjiang1989/alpine:golang-1.18.8-alpine3.15                                                  0.7s
 => CANCELED [linux/ppc64le internal] load metadata for docker.io/dongjiang1989/alpine:golang-1.18.8-alpine3.15                                                 0.7s
 => CANCELED [linux/arm64 internal] load metadata for docker.io/dongjiang1989/alpine:golang-1.18.8-alpine3.15                                                   0.7s
 => CANCELED [linux/riscv64 internal] load metadata for docker.io/dongjiang1989/alpine:golang-1.18.8-alpine3.15                                                 0.7s
 => CANCELED [linux/s390x internal] load metadata for docker.io/dongjiang1989/alpine:golang-1.18.8-alpine3.15                                                   0.7s
 => CANCELED [linux/arm/v7 internal] load metadata for docker.io/dongjiang1989/alpine:golang-1.18.8-alpine3.15                                                  0.7s
 => CANCELED [linux/amd64 internal] load metadata for docker.io/dongjiang1989/alpine:golang-1.18.8-alpine3.15                                                   0.7s
 => CANCELED [linux/386 internal] load metadata for docker.io/dongjiang1989/alpine:golang-1.18.8-alpine3.15  
......

check多架构镜像

dongjiang@MacBook Pro:muti-arch $ docker manifest inspect dongjiang1989/muti-arch-demo-server:latest
{
   "schemaVersion": 2,
   "mediaType": "application/vnd.docker.distribution.manifest.list.v2+json",
   "manifests": [
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1679,
         "digest": "sha256:786d66907396720dc98cf332f9d59dc423c0a28791e1f63d4f002f7ebb73bb4c",
         "platform": {
            "architecture": "386",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1679,
         "digest": "sha256:2e97c5212297685386fa22b8155b75f4ac2f758705c253cbe6707a48a8011497",
         "platform": {
            "architecture": "amd64",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1679,
         "digest": "sha256:e41b2fad89dc900ef10376a82ab4fd70a0a739a04d57d96b2589f938eca99b83",
         "platform": {
            "architecture": "arm",
            "os": "linux",
            "variant": "v6"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1679,
         "digest": "sha256:e8d64dfa17f80eb3cc7bf4ccc648c0136e40b507272de1151fcfc13534cddaa8",
         "platform": {
            "architecture": "arm",
            "os": "linux",
            "variant": "v7"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1679,
         "digest": "sha256:394e182faddaa3b168f9e976f88900623c51e561d808d951e32a08e037acf591",
         "platform": {
            "architecture": "arm64",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1679,
         "digest": "sha256:d2e537ab91efb65344017ec40142cc09aa2b615ee0ef11aa5d6a9bf897861430",
         "platform": {
            "architecture": "ppc64le",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1679,
         "digest": "sha256:c1f25a3aa9744f8a00f533c736abad0d23eff5d32908b426b37387829f4122e0",
         "platform": {
            "architecture": "s390x",
            "os": "linux"
         }
      }
   ]
}

总结

1. docker 需要 使用dockerx编译
2. 编译平台需要支持qemu切换gcc
3. 基础镜像也需要支持多架构
4. Dockerfile编译指令中，不能写死GOARCH、GOOS
5. 业务代码中，需要支持多架构代码；比如syscall, os调用等