docker_basic_dockerize

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docker_basic_dockerize [2020/01/24 18:43] – created andonovjdocker_basic_dockerize [2020/05/03 11:49] (current) – [Wrong ASP.NET] andonovj
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 =====Steps===== =====Steps=====
-Firstly, you need a Dockerfile in the place of your project:+Firstly, you need a Dockerfile in the place of your project. 
 +Since my project is on C#.NET Core and assuming your application is called: HttpServerDemo.dll, I have used the following Dockerfile:
  
 +==Dockerfile==
 +<sxh bash>
 +FROM mcr.microsoft.com/dotnet/core/sdk:3.1 AS build-env
 +WORKDIR /app
  
 +# Copy csproj and restore as distinct layers
 +COPY *.csproj ./
 +RUN dotnet restore
  
 +# Copy everything else and build
 +COPY . ./
 +RUN dotnet publish -c Release -o out
 +
 +# Build runtime image
 +FROM mcr.microsoft.com/dotnet/core/aspnet:2.2
 +WORKDIR /app
 +COPY --from=build-env /app/out .
 +ENTRYPOINT ["dotnet", "HttpServerDemo.dll"]
 +</sxh>
 +
 +Now, let's go through the steps:
 +  * Workdir - The workdir on the container which will be used.
 +  * FROM -  The external resources which will be used.
 +  * COPY & RUN - These are self explanatory I hope.
 +
 +You have to verify you have docker at least 17.05 or newer. 
 +My current one is 19.03:
 +
 +<sxh bash>
 +[root@postgresqlpgpool netcoreapp3.1]# docker --version
 +Docker version 19.03.5, build 633a0ea
 +</sxh>
 +
 +
 +====Build====
 +The building is also done fairy simple.
 +
 +<sxh bash>
 +[root@postgresqlpgpool HttpServerDemo]# docker build -t httpserverdemo .
 +Sending build context to Docker daemon  398.3kB
 +Step 1/10 : FROM mcr.microsoft.com/dotnet/core/sdk:3.1 AS build-env
 + ---> 2fe8fe202baf
 +Step 2/10 : WORKDIR /app
 + ---> Using cache
 + ---> 931056fe84ac
 +Step 3/10 : COPY *.csproj ./
 + ---> Using cache
 + ---> 33c701ccd6cf
 +Step 4/10 : RUN dotnet restore
 + ---> Using cache
 + ---> 2acbc600037a
 +Step 5/10 : COPY . ./
 + ---> 68177b9bdcf6
 +Step 6/10 : RUN dotnet publish -c Release -o out
 + ---> Running in 34db589b7d0b
 +Microsoft (R) Build Engine version 16.4.0+e901037fe for .NET Core
 +Copyright (C) Microsoft Corporation. All rights reserved.
 +
 +  Restore completed in 127.94 ms for /app/HttpServerDemo.csproj.
 +  HttpServerDemo -> /app/bin/Release/netcoreapp3.1/HttpServerDemo.dll
 +  HttpServerDemo -> /app/out/
 +Removing intermediate container 34db589b7d0b
 + ---> d81f005279bc
 +Step 7/10 : FROM mcr.microsoft.com/dotnet/core/aspnet:3.1
 + ---> 5b704ff3cb6b
 +Step 8/10 : WORKDIR /app
 + ---> Using cache
 + ---> e35d6ba6b507
 +Step 9/10 : COPY --from=build-env /app/out .
 + ---> dc3b27c05e4d
 +Step 10/10 : ENTRYPOINT ["dotnet", "HttpServerDemo.dll"]
 + ---> Running in ff14d57a08fc
 +Removing intermediate container ff14d57a08fc
 + ---> 46b4167e5b2d
 +Successfully built 46b4167e5b2d
 +Successfully tagged httpserverdemo:latest
 +[root@postgresqlpgpool HttpServerDemo]#
 +</sxh>
 +
 +
 +You can list the images as follows:
 +
 +<sxh bash>
 +[root@postgresqlpgpool netcoreapp3.1]# docker images
 +REPOSITORY                             TAG                 IMAGE ID            CREATED             SIZE
 +httpserverdemo                         latest              4ab730ac8ab5        6 hours ago         207MB
 +</sxh>
 +
 +====Start====
 +Once the image has been built, you can start the container using that image:
 +
 +<sxh bash>
 +[root@postgresqlpgpool HttpServerDemo]# docker run -d httpserverdemo 80:1234
 +c23e4bb41a9f660f8b409addb58d398b98dce38e93da00682214141f5bc719c9
 +[root@postgresqlpgpool HttpServerDemo]#
 +</sxh>
 +
 +Finally, you can check the container:
 +
 +<sxh bash>
 +[root@postgresqlpgpool netcoreapp3.1]# docker container ls
 +CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                  NAMES
 +9afb2dcbd6c2        httpserverdemo      "dotnet HttpServerDe…"   5 hours ago         Up 5 hours          0.0.0.0:80->1234/tcp   web
 +[root@postgresqlpgpool netcoreapp3.1]#
 +</sxh>
 +
 +
 +====Upload in docker hub====
 +Docker hub is the default registry for docker images. You can upload your image there if you want, bare in mind that it will be public.
 +
 +==Login==
 +<sxh bash>
 +[root@postgresqlpgpool netcoreapp3.1]# docker login --username=andonovj
 +Password:
 +WARNING! Your password will be stored unencrypted in /root/.docker/config.json.
 +Configure a credential helper to remove this warning. See
 +https://docs.docker.com/engine/reference/commandline/login/#credentials-store
 +
 +Login Succeeded
 +[root@postgresqlpgpool netcoreapp3.1]# 
 +</sxh>
 +
 +==Package==
 +<sxh bash>
 +[root@postgresqlpgpool netcoreapp3.1]# docker images
 +REPOSITORY                             TAG                 IMAGE ID            CREATED             SIZE
 +httpserverdemo                         latest              4ab730ac8ab5        3 hours ago         207MB
 +[root@postgresqlpgpool netcoreapp3.1]# docker tag 4ab730ac8ab5 andonovj/httpserverdemo
 +</sxh>
 +
 +==Push==
 +<sxh bash>
 +[root@postgresqlpgpool netcoreapp3.1]# docker push andonovj/httpserverdemo
 +The push refers to repository [docker.io/andonovj/httpserverdemo]
 +6f2df37fa757: Pushed
 +64bca5e22c97: Pushed
 +05682a6a4056: Pushed
 +fcd021389694: Pushed
 +2c52aed6692d: Pushed
 +c51868eee26f: Pushed
 +556c5fb0d91b: Pushed
 +latest: digest: sha256:5e0866ff45e12c8e350923fbe32d94bd76bd2d1576722d4d55ca786043bfcbe1 size: 1791
 +[root@postgresqlpgpool netcoreapp3.1]#
 +</sxh>
 +
 +Now you can also download this simple web from your docker hub or list it as follows:
 +
 +<sxh bash>
 +[root@postgresqlpgpool ~]# docker images
 +REPOSITORY                             TAG                 IMAGE ID            CREATED             SIZE
 +andonovj/httpserverdemo                latest              4ab730ac8ab5        6 hours ago         207MB
 +[root@postgresqlpgpool ~]#
 +</sxh>
 +
 +=====Troubleshooting=====
 +You can have the following error:
 +
 +
 +====Searching wrong Nuget====
 +<Code: C#|Nuget Issue>
 +  Restore completed in 41.36 ms for /app/HttpServerDemo.csproj.
 +/usr/share/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk/targets/Microsoft.PackageDependencyResolution.targets(234,5): error MSB4018: The "ResolvePackageAssets" task failed unexpectedly. [/app/HttpServerDemo.csproj]
 +/usr/share/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk/targets/Microsoft.PackageDependencyResolution.targets(234,5): error MSB4018: NuGet.Packaging.Core.PackagingException: Unable to find fallback package folder 'C:\Program Files\dotnet\sdk\NuGetFallbackFolder'. [/app/HttpServerDemo.csproj]
 +/usr/share/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk/targets/Microsoft.PackageDependencyResolution.targets(234,5): error MSB4018:    at NuGet.Packaging.FallbackPackagePathResolver..ctor(String userPackageFolder, IEnumerable`1 fallbackPackageFolders) [/app/HttpServerDemo.csproj]
 +/usr/share/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk/targets/Microsoft.PackageDependencyResolution.targets(234,5): error MSB4018:    at Microsoft.NET.Build.Tasks.NuGetPackageResolver.CreateResolver(IEnumerable`1 packageFolders) [/app/HttpServerDemo.csproj]
 +/usr/share/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk/targets/Microsoft.PackageDependencyResolution.targets(234,5): error MSB4018:    at Microsoft.NET.Build.Tasks.NuGetPackageResolver.CreateResolver(LockFile lockFile) [/app/HttpServerDemo.csproj]
 +/usr/share/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk/targets/Microsoft.PackageDependencyResolution.targets(234,5): error MSB4018:    at Microsoft.NET.Build.Tasks.ResolvePackageAssets.CacheWriter..ctor(ResolvePackageAssets task) [/app/HttpServerDemo.csproj]
 +/usr/share/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk/targets/Microsoft.PackageDependencyResolution.targets(234,5): error MSB4018:    at Microsoft.NET.Build.Tasks.ResolvePackageAssets.CacheReader.CreateReaderFromDisk(ResolvePackageAssets task, Byte[] settingsHash) [/app/HttpServerDemo.csproj]
 +/usr/share/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk/targets/Microsoft.PackageDependencyResolution.targets(234,5): error MSB4018:    at Microsoft.NET.Build.Tasks.ResolvePackageAssets.CacheReader..ctor(ResolvePackageAssets task) [/app/HttpServerDemo.csproj]
 +/usr/share/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk/targets/Microsoft.PackageDependencyResolution.targets(234,5): error MSB4018:    at Microsoft.NET.Build.Tasks.ResolvePackageAssets.ReadItemGroups() [/app/HttpServerDemo.csproj]
 +/usr/share/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk/targets/Microsoft.PackageDependencyResolution.targets(234,5): error MSB4018:    at Microsoft.NET.Build.Tasks.ResolvePackageAssets.ExecuteCore() [/app/HttpServerDemo.csproj]
 +/usr/share/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk/targets/Microsoft.PackageDependencyResolution.targets(234,5): error MSB4018:    at Microsoft.NET.Build.Tasks.TaskBase.Execute() [/app/HttpServerDemo.csproj]
 +/usr/share/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk/targets/Microsoft.PackageDependencyResolution.targets(234,5): error MSB4018:    at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute() [/app/HttpServerDemo.csproj]
 +/usr/share/dotnet/sdk/3.1.201/Sdks/Microsoft.NET.Sdk/targets/Microsoft.PackageDependencyResolution.targets(234,5): error MSB4018:    at Microsoft.Build.BackEnd.TaskBuilder.ExecuteInstantiatedTask(ITaskExecutionHost taskExecutionHost, TaskLoggingContext taskLoggingContext, TaskHost taskHost, ItemBucket bucket, TaskExecutionMode howToExecuteTask) [/app/HttpServerDemo.csproj]
 +The command '/bin/sh -c dotnet publish -c Release -o out' returned a non-zero code: 1
 +</Code>
 +
 +In that case, either:
 +
 +  * Delete the "obj" and "bin" folders from the directory
 +  * Add a command to the "Dockerfile" to not upload these to the container as follows:
 +
 +<Code: bash| Edit Dockerfile>
 +# copy and build everything else
 +COPY . ./
 +RUN find -type d -name bin -prune -exec rm -rf {} \; && find -type d -name obj -prune -exec rm -rf {} \;     <- This line
 +ENTRYPOINT ["dotnet", "HttpServerDemo.dll"]
 +</Code>
 +
 +
 +====Wrong ASP.NET====
 +Be careful about the dockerizing the application. I tried to build the application with ASP.NET 2.2 while the app was build with ASP.NET 3.1, so I had to update my Dockerfile as follows:
 +
 +<Code: bash| Updated Docker File>
 +FROM mcr.microsoft.com/dotnet/core/sdk:3.1 AS build-env                     <- This line
 +WORKDIR /app
 +
 +# Copy csproj and restore as distinct layers
 +COPY *.csproj ./
 +RUN dotnet restore
 +
 +# Copy everything else and build
 +COPY . ./
 +RUN dotnet publish -c Release -o out
 +
 +# Build runtime image
 +#FROM mcr.microsoft.com/dotnet/core/aspnet:2.2
 +FROM mcr.microsoft.com/dotnet/core/sdk:3.1
 +WORKDIR /app
 +COPY --from=build-env /app/out .
 +ENTRYPOINT ["dotnet", "HttpServerDemo.dll"]
 +</Code>
 +
 +Otherwise, you will receive the following error:
 +
 +<Code: bash| Error for wrong ASP.NET version>
 +It was not possible to find any compatible framework version
 +The specified framework 'Microsoft.NETCore.App', version '3.1.0' was not found.
 +  - Check application dependencies and target a framework version installed at:
 +      /usr/share/dotnet/
 +  - Installing .NET Core prerequisites might help resolve this problem:
 +      https://go.microsoft.com/fwlink/?LinkID=798306&clcid=0x409
 +  - The .NET Core framework and SDK can be installed from:
 +      https://aka.ms/dotnet-download
 +  - The following versions are installed:
 +      2.2.8 at [/usr/share/dotnet/shared/Microsoft.NETCore.App]
 +</Code>
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  • Last modified: 2020/01/25 02:43
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