ASP.NET Core Docker Container App not accessible

docker asp.net-core https

10,438

Solution 1

Turns out this is a bug in Visual Studio for Mac v18.1.2 (docker-compose up works)

Solution 2

I had your problem a while ago, this is how I fixed it. You need to specify --server.urls as a running argument like below:

FROM base AS final
WORKDIR /app
COPY --from=publish /app .
ENTRYPOINT ["dotnet", "Service.API.dll", "--server.urls", "http://+:80;https://+:443"]

And where that 5000 and 5001 come from?

Kestrel Endpoint configuration

By default, ASP.NET Core binds to:

http://localhost:5000

https://localhost:5001 (when a local development certificate is present)

Update 1:

According to your docker-compose configuration, you have set ASPNETCORE_ENVIRONMENT to Development. I think you should change it to Production because when you enable Development the ASP.NET Core will read settings from launchSettings.json.

The development environment can enable features that shouldn't be exposed in production. For example, the ASP.NET Core templates enable the Developer Exception Page in the development environment.

The environment for local machine development can be set in the Properties\launchSettings.json file of the project. Environment values set in launchSettings.json override values set in the system environment.

As far as I remember the default ports for Kestrel are 80 and 443 in every default launchSettings.json.

If you need to run your project in development mode on Docker you should change configuration inside launchSettings.json but I think it's not recommended and it's better to change the mode to Production.

service.api:
  build:
    context: .
    dockerfile: src/Services/Service.API/Dockerfile
  environment:
    - ASPNETCORE_ENVIRONMENT=Production
    - ASPNETCORE_URLS=http://+:80;https://+:443
    - ASPNETCORE_HTTPS_PORT=5254 
    - ASPNETCORE_Kestrel__Certificates__Default__Password=crypticpassword
    - ASPNETCORE_Kestrel__Certificates__Default__Path=/https/aspnetapp.pfx
  ports:
    - "5204:80"
    - "5254:443"
  volumes:
    - ${HOME}/.aspnet/https:/https/

Solution 3

Basically, in the asp.net core code, it only listens to localhost which is in Container, but not your local pc. You can solve the issue by updating your setting to listen "http://*:5000" instead of "http://localhost:5000".

Here is a detailed explaination of the cause and solution. https://stackoverflow.com/a/65953771/8918445

10,438

Palmi

Updated on June 04, 2022

Comments

Palmi almost 2 years

I run an ASP.NET Core service in a Docker container on MacOS.
Visual Studio for Mac v18.1.2 (build 2) .NET Core SDK: 2.2.300

Here is the Dockerfile:

FROM mcr.microsoft.com/dotnet/core/aspnet:2.2 AS base
WORKDIR /app
EXPOSE 80
EXPOSE 443

FROM mcr.microsoft.com/dotnet/core/sdk:2.2 AS build
WORKDIR /
COPY src/Services/Service.API/Service.API.csproj src/Services/Service.API/
RUN dotnet restore src/Services/Service.API/Service.API.csproj
COPY . .
WORKDIR /src/Services/Service.API
RUN dotnet build Service.API.csproj -c Release -o /app

FROM build AS publish
RUN dotnet publish Service.API.csproj -c Release -o /app

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

Here is how the docker-compose file for the service looks like:

service.api:
  build:
    context: .
    dockerfile: src/Services/Service.API/Dockerfile
  environment:
    - ASPNETCORE_ENVIRONMENT=Development
    - ASPNETCORE_URLS=http://+:80;https://+:443
    - ASPNETCORE_HTTPS_PORT=5254 
    - ASPNETCORE_Kestrel__Certificates__Default__Password=crypticpassword
    - ASPNETCORE_Kestrel__Certificates__Default__Path=/https/aspnetapp.pfx
  ports:
    - "5204:80"
    - "5254:443"
  volumes:
    - ${HOME}/.aspnet/https:/https/

The ports of the running Docker container looks good too:

0.0.0.0:5204->80/tcp, 0.0.0.0:5254->443/tcp

But when I try to call https://localhost:5254 it says site cannot be reached.

Also in the output I see following warning:

warn: Microsoft.AspNetCore.Server.Kestrel[0] Unable to bind to https://localhost:5001 on the IPv6 loopback interface: 'Cannot assign requested address'. Microsoft.AspNetCore.Server.Kestrel:Warning: Unable to bind to https://localhost:5001 on the IPv6 loopback interface: 'Cannot assign requested address'. Hosting environment: Development Content root path: /app Now listening on: https://localhost:5001

Why doesn't it take the urls set by the ASPNETCORE_URLS enivronment variable?

What else could I do for troubleshooting to find the problem?

Palmi almost 5 years

container is up and running. Regarding the entrypoint, I added the Dockerfile in my question
nPcomp almost 5 years

Did you check the Kestrel? Is it running too?
Palmi almost 5 years

How do I check it in the container?
nPcomp almost 5 years

Just do docker exec -it your_container /bin/bash
nPcomp almost 5 years

Or docker logs your_container if you want to follow the logs use: docker logs -f your_container syntax
Palmi almost 5 years

dotnet Service.API.dll in the container returns: Did you mean to run dotnet SDK commands? Please install dotnet SDK from: go.microsoft.com/fwlink/?LinkID=798306&clcid=0x409
Palmi almost 5 years

Thanks, but this didn't help. Same problem. Also according to your link you can use the ASPNETCORE_URLS environment variable, what I do, but it seems to just ignore it and use the default bindings.
Palmi almost 5 years

I removed it in my question. I just tried to merge the the docker-compose.yml and docker-compose.override.yml to simplify it for the question...
Edward almost 5 years

@Palmi What do you mean by merge docker-compose.yam and docker-compose.override.yml? Run docker container -ls -a to see whether there is any container with image name service.api, remove them and run docker-compose up again. Not sure whether you configured anywhere, try to use this dockerfile and docker-compose with a new default .net core project.
Ali Bahrami almost 5 years

@Palmi I see, I updated the answer please take a look.
NyoNor over 2 years

On windows 10 using docker desktop and linux containers it's not accessible too...