Docker容器端口6002连接被拒绝

Question

Operating System: Docker for Windows. OSType: linux. Architecture: x86_64

I have an ASP.NET core web app running inside a Docker container. The below is my Dockerfile.

FROM microsoft/dotnet:2.1-aspnetcore-runtime AS base
WORKDIR /app
EXPOSE 6002

FROM microsoft/dotnet:2.1-sdk AS build
WORKDIR /src
COPY ["AdvPersonApi.csproj", "AdvPersonApi/"]
RUN dotnet restore "AdvPersonApi/AdvPersonApi.csproj"
COPY . ./AdvPersonApi/
WORKDIR "/src/AdvPersonApi"
RUN dotnet build "AdvPersonApi.csproj" -c Release -o /app

FROM build AS publish
RUN dotnet publish "AdvPersonApi.csproj" -c Release -o /app

FROM base AS final
WORKDIR /app
COPY --from=publish /app .
EXPOSE 6002
ENTRYPOINT ["dotnet", "AdvPersonApi.dll"]

The app builds successfully. I also am able to create the Docker image, and run it. I want the app to be accessible at localhost:6002. I used the below command to create the container:

docker run -p 6002:6002 --name advpersonapicontainerv2 advpersonapi:v2

I see that the containers are created and running.

The below is the result of docker ps:

CONTAINER ID        IMAGE               COMMAND                  CREATED              STATUS              PORTS                    NAMES
0484b184aeb8        advpersonapi:v2     "dotnet AdvPersonApi…"   About a minute ago   Up About a minute   0.0.0.0:6002->6002/tcp   advpersonapicontainerv2

The issue is that I am not able to access the app at Container port 6002. The below command gives connection refused:

    docker exec 0484b184aeb8 curl http://localhost:6002/api/person/time
     % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                     Dload  Upload   Total   Spent    Left  Speed
      0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
curl: (7) Failed to connect to localhost port 6002: Connection refused

However, if I try

docker exec 0484b184aeb8 curl http:// localhost:80 /api/person/time

, I get the response. I am new to Docker. What should I do to map the host port 6002 correctly to the container port 6002?

Answer 1

I figured out what is going on. I had to force Kestrel to listen to port 6002, by adding the below to the appsettings.json.

 "Kestrel": {
    "EndPoints": {
      "Http": {
        "Url": "http://+:6002"
      }
    }
  }

Credit to the hint provided by @Timothy John Laird in the above comment

Answer 2

The app inside the container is listening on 80, so in your Dockerfile expose port 80 instead of 6002.

EXPOSE 80

Then map host port 6002 to container port 80 when you run the container:

docker run -p 6002:80 --name advpersonapicontainerv2 advpersonapi:v2

It's best to have containerized apps listening on standard ports like 80 or 8000. You don't want to update the Dockerfile to get it to listen to other ports. That's the job of the runtime mapping at the host level.