C#•2mo ago

✅ .Net 8 WebApi not responding from Docker container

I am running a default .Net 8 webapi project that I created via the dotnet CLI

dotnet new webapi -n dotnetapi

dotnet new webapi -n dotnetapi

The project builds and runs locally, I am able to get a response. Dockerfile

FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
WORKDIR /app
EXPOSE 80

FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build
WORKDIR /src
COPY . .
RUN dotnet restore
RUN dotnet build -c Release -o /app/build

FROM build AS publish
RUN dotnet publish -c Release -o /app/publish

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

FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
WORKDIR /app
EXPOSE 80

FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build
WORKDIR /src
COPY . .
RUN dotnet restore
RUN dotnet build -c Release -o /app/build

FROM build AS publish
RUN dotnet publish -c Release -o /app/publish

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

I build the image and run it

docker run -p 5154:80 dotnet-api

docker run -p 5154:80 dotnet-api

Cannot get a response from the api

curl http://localhost:5154/weatherforecast

curl http://localhost:5154/weatherforecast

Any help appreciated!

6 Replies

cap5lut•2mo ago

what do the logs of the container say which port kestrel is listening on?

Pobiega•2mo ago

Highly doubt kestrel is listening to 80 so yeah, check the container logs for the

info: Microsoft.Hosting.Lifetime[14]
Now listening on: http://localhost:xxxx

info: Microsoft.Hosting.Lifetime[14]
Now listening on: http://localhost:xxxx

message thats the port you need to expose and map up as your in-container port

Unknown User•2mo ago

Message Not Public

SOMUCHDOG•2mo ago

Thanks for the response guys.. I've been at work so I couldn't get answers out. Here's the logs. I'm just getting started with Docker, so I am trying to understand a bit here. I exposed 80, Kestrel is listening on 8080, so traffic is not getting to the container since it's listening on the wrong port?

Unknown User•2mo ago

Message Not Public

cap5lut•2mo ago

the -p 5154:80 part of the docker run command means that u tunnel/bind the host port 5154 to the container internal's port 80. Now listening on http://0.0.0.0:5154 means that its listening for any IP on port 5154, which is within the docker container. so basically, if u swap the ports to -p 80:5154, requests like http://localhost/weatherforecast would do the trick here, to make it work. and that weird port configuration, as TeBeCo already mentioned, should be investigated as well.

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✅ .Net 8 WebApi not responding from Docker container