在devops流程里面 構(gòu)建鏡像是一個(gè)非常重要的過(guò)程,一般構(gòu)建鏡像是寫(xiě)dockerfile文件然后通過(guò)docker client來(lái)構(gòu)建的image。
docker client 會(huì)先檢查本地有沒(méi)有image,如果沒(méi)有幫你 從鏡像倉(cāng)庫(kù) pull 下來(lái)
然后解析你寫(xiě)的dockerfile構(gòu)建新的image。
本文帶你了解
下篇文章帶你解析:
如果我不用docker 我如何構(gòu)建一個(gè)鏡像?
我們以微軟的aspnet2.2為基礎(chǔ)構(gòu)建一個(gè)aspnetcore項(xiàng)目的鏡像為例子
mcr.microsoft.com/dotnet/core/aspnet:2.2
根據(jù)基礎(chǔ)鏡像REGISTRY去獲取mainfest信息
https://mcr.microsoft.com/v2/dotnet/core/aspnet/manifests/2.2 Accept: application/vnd.oci.image.manifest.v1+json,application/vnd.docker.distribution.manifest.v2+json,application/vnd.docker.distribution.manifest.v1+json
獲取到的內(nèi)容如下:
{ "schemaVersion": 2, "mediaType": "application/vnd.docker.distribution.manifest.v2+json", "config": { "mediaType": "application/vnd.docker.container.image.v1+json", "size": 4039, "digest": "sha256:e7e3b238011ce0f2b9350153535fe273caa01f0e7188d0b91f965b3802ddc600" }, "layers": [ { "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip", "size": 22524609, "digest": "sha256:804555ee037604c40de144f9f8da0d826d38db82f15d74cded32790fe279a8f6" }, { "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip", "size": 17692725, "digest": "sha256:970251047358aea56ba6db6975b14ff12470b75de0c2477f4445240ddd727fd4" }, { "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip", "size": 2978257, "digest": "sha256:f3d4c41a4fd13f35c0b46f19a4e27845f4695163cc7174d908ff84836bbc2f5a" }, { "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip", "size": 62145592, "digest": "sha256:bd391c46585f9f8d84992bbaa9087189148c1601968eaaf097d5b3ed60840e5e" } ] }
mainfest文件里面都是摘要(digest)記錄
根據(jù)上面的config信息摘要獲取config詳情
GET:https://mcr.microsoft.com/v2/dotnet/core/aspnet/blobs/sha256:e7e3b238011ce0f2b9350153535fe273caa01f0e7188d0b91f965b3802ddc600
{ "architecture": "amd64", "config": { "Hostname": "", "Domainname": "", "User": "", "AttachStdin": false, "AttachStdout": false, "AttachStderr": false, "Tty": false, "OpenStdin": false, "StdinOnce": false, "Env": [ "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin", "ASPNETCORE_URLS=http://+:80", "DOTNET_RUNNING_IN_CONTAINER=true", "ASPNETCORE_VERSION=2.2.8" ], "Cmd": [ "bash" ], "ArgsEscaped": true, "Image": "sha256:5ecfe4016ac8e911a94aa601a675f7204e9ccab00cbb08e7067c184ad40f34e9", "Volumes": null, "WorkingDir": "", "Entrypoint": null, "OnBuild": null, "Labels": null }, "container": "14196c2f9c327d41e26682d32c7c89c4e7c78aa32f8b7501a23192035a9f4844", "container_config": { "Hostname": "", "Domainname": "", "User": "", "AttachStdin": false, "AttachStdout": false, "AttachStderr": false, "Tty": false, "OpenStdin": false, "StdinOnce": false, "Env": [ "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin", "ASPNETCORE_URLS=http://+:80", "DOTNET_RUNNING_IN_CONTAINER=true", "ASPNETCORE_VERSION=2.2.8" ], "Cmd": [ "/bin/sh", "-c", "curl -SL --output aspnetcore.tar.gz https://dotnetcli.azureedge.net/dotnet/aspnetcore/Runtime/$ASPNETCORE_VERSION/aspnetcore-runtime-$ASPNETCORE_VERSION-linux-x64.tar.gz && aspnetcore_sha512='954072376698be69acb7e277df2c243f931e10529def21dcbf9ce277609b30d462126bf8b8b3cab36476bec3d63a927b8e44e59e4d4cade23eef45956fba1ffd' && echo \"$aspnetcore_sha512 aspnetcore.tar.gz\" | sha512sum -c - && mkdir -p /usr/share/dotnet && tar -zxf aspnetcore.tar.gz -C /usr/share/dotnet && rm aspnetcore.tar.gz && ln -s /usr/share/dotnet/dotnet /usr/bin/dotnet" ], "Image": "sha256:5ecfe4016ac8e911a94aa601a675f7204e9ccab00cbb08e7067c184ad40f34e9", "Volumes": null, "WorkingDir": "", "Entrypoint": null, "OnBuild": null, "Labels": null }, "created": "2019-12-28T08:12:05.676492579Z", "docker_version": "3.0.8", "history": [ { "created": "2019-12-28T04:23:47.4966447Z", "created_by": "/bin/sh -c #(nop) ADD file:90a2c81769a336bed3f731f44a385f2a65b0916f517a0b77c06c224579bf9a9a in / " }, { "created": "2019-12-28T04:23:47.719507596Z", "created_by": "/bin/sh -c #(nop) CMD [\"bash\"]", "empty_layer": true }, { "created": "2019-12-28T08:11:05.607009582Z", "created_by": "/bin/sh -c apt-get update && apt-get install -y --no-install-recommends ca-certificates libc6 libgcc1 libgssapi-krb5-2 libicu57 liblttng-ust0 libssl1.0.2 libstdc++6 zlib1g && rm -rf /var/lib/apt/lists/*" }, { "created": "2019-12-28T08:11:07.64336022Z", "created_by": "/bin/sh -c #(nop) ENV ASPNETCORE_URLS=http://+:80 DOTNET_RUNNING_IN_CONTAINER=true", "empty_layer": true }, { "created": "2019-12-28T08:11:16.475068844Z", "created_by": "/bin/sh -c apt-get update && apt-get install -y --no-install-recommends curl && rm -rf /var/lib/apt/lists/*" }, { "created": "2019-12-28T08:11:43.814078508Z", "created_by": "/bin/sh -c #(nop) ENV ASPNETCORE_VERSION=2.2.8", "empty_layer": true }, { "created": "2019-12-28T08:12:05.676492579Z", "created_by": "/bin/sh -c curl -SL --output aspnetcore.tar.gz https://dotnetcli.azureedge.net/dotnet/aspnetcore/Runtime/$ASPNETCORE_VERSION/aspnetcore-runtime-$ASPNETCORE_VERSION-linux-x64.tar.gz && aspnetcore_sha512='954072376698be69acb7e277df2c243f931e10529def21dcbf9ce277609b30d462126bf8b8b3cab36476bec3d63a927b8e44e59e4d4cade23eef45956fba1ffd' && echo \"$aspnetcore_sha512 aspnetcore.tar.gz\" | sha512sum -c - && mkdir -p /usr/share/dotnet && tar -zxf aspnetcore.tar.gz -C /usr/share/dotnet && rm aspnetcore.tar.gz && ln -s /usr/share/dotnet/dotnet /usr/bin/dotnet" } ], "os": "linux", "rootfs": { "type": "layers", "diff_ids": [ "sha256:814c70fdae62bc26c603bfae861f00fb1c77fc0b1ee8d565717846f4df24ae5d", "sha256:0cf75cb98eb2e0a82631d4aff71b40ba79ff7f83e0361f696875e592a1a4cefc", "sha256:15e45d99c92686fb1fd61a41431d8400d7a0e8381595d09d666b0809c4f5d993", "sha256:579a8f1d6a123f98095c0b1a1395079f7504391fd2a8bc529dede305a2072a36" ] } }
根據(jù)diff_ids里面去下載對(duì)應(yīng)layers
下載完后對(duì)比摘要一致,確保鏡像文件合法性
路徑規(guī)則:
https://mcr.microsoft.com/v2/dotnet/core/aspnet/blobs/sha256:XXXXXX
在基礎(chǔ)鏡像的配置基礎(chǔ)上加入我們的自定義配置
在基礎(chǔ)鏡像的所有的layers把我們要打包到鏡像也做成一個(gè)layer
生成的鏡像tar包解壓出來(lái)
多了一個(gè) tar.gz文件,解壓之后 就是我們打包放進(jìn)去的文件
config.json對(duì)比與基礎(chǔ)鏡像
我們來(lái)復(fù)習(xí)下構(gòu)建鏡像的過(guò)程 根據(jù)鏡像名稱拉取mainfest
知道原理后我們可以自己寫(xiě)一個(gè)工具來(lái)實(shí)現(xiàn)整個(gè)過(guò)程
我開(kāi)源的docker鏡像構(gòu)建,讓你不用裝docker也能快速構(gòu)建容器鏡像
支持以下鏡像倉(cāng)庫(kù)作為基礎(chǔ)鏡像構(gòu)建
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標(biāo)簽:石嘴山 汕頭 三明 拉薩 玉林 開(kāi)封 晉城 鄭州
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