96 lines
6.8 KiB
Markdown
96 lines
6.8 KiB
Markdown
# net-base
|
|
|
|
Base docker file that allows you to deploy .NET wit ease.
|
|
Microsoft makes some images available to deploy .NET applications in Docker.
|
|
However in order to use them, there is need for some tweaking.
|
|
|
|
This image is based on the *mcr.microsoft.com/dotnet/aspnet* image, but includes these tweaks.
|
|
Among other things these tweaks are included :
|
|
- automatic generation of certificate for the web server
|
|
- disable telemetry
|
|
- inclusion of tzdata for time setup
|
|
|
|
|
|
## Docker image
|
|
|
|
### Usage
|
|
|
|
Since this is just a base image, some additional setup is needed.
|
|
The following is just an example of how your Dockerfile could look like.
|
|
|
|
```sh
|
|
# Password for the certificate
|
|
# this image contains the entire .NET SDK and is ideal for creation the build
|
|
FROM mcr.microsoft.com/dotnet/sdk:8.0-alpine-amd64 AS build-env
|
|
WORKDIR /App
|
|
COPY . ./
|
|
# Restore dependencies for your application
|
|
RUN dotnet restore
|
|
# Build your application
|
|
RUN dotnet publish test.csproj --no-restore --self-contained false -c Release -o out /p:UseAppHost=false
|
|
|
|
FROM git.claeyscloud.com/david/net-base:latest
|
|
WORKDIR /App
|
|
# copy build files from build-stage
|
|
COPY --from=build-env /App/out .
|
|
# change ownership of files to the app user
|
|
RUN chown -R app:app /App/
|
|
# entrypoint for image
|
|
ENTRYPOINT ["dotnet", "test.dll"]
|
|
```
|
|
|
|
### Environment Variables
|
|
|
|
| Variable | Description | Default |
|
|
|-----------------------------------------------------|-------------------------------------------------------------------------|----------------------------------------------------------------------------------------------|
|
|
| ASPNETCORE_Kestrel__Certificates__Default__Path | The path containing the server certificate | /usr/local/share/ca-certificates/aspnetapp.crt |
|
|
| ASPNETCORE_Kestrel__Certificates__Default__KeyPath | The path containing the key for the server certificate | /usr/local/share/ca-certificates/aspnetapp.key |
|
|
| ASPNETCORE_Kestrel__Certificates__Default__Password | The password for required for the server key | N/A (generated at build time) |
|
|
| CERTIFICATES_DIRECTORY | The directory where the certificate files are stored for the web server | /usr/local/share/ca-certificates |
|
|
| ASPNETCORE_URLS | Specifies at which urls and ports the Kestrel server should listen | http://+:80;https://+:443 |
|
|
| DOTNET_CLI_TELEMETRY_OPTOUT | Disables telemetry | 1 |
|
|
| TZ | Time zone ([list](https://en.wikipedia.org/wiki/List_of_tz_database_time_zones#List)) | Europe/Brussels | |
|
|
|
|
### Build arguments
|
|
|
|
These are the most important build arguments. Most of them are optional, meaning you can tweak them if you so desire.
|
|
However the *CERT_PASSWORD* argument is required, as it's necesarry in order to build a working image.
|
|
|
|
You can build the image yourself like this
|
|
|
|
```sh
|
|
docker build --build-arg CERT_PASSWORD=supersecretpassword . -t net-base
|
|
```
|
|
|
|
| Argument | Description | Default |
|
|
|-----------------------------------------------------|-------------------------------------------------------------------------|----------------------------------------------------------------------------------------------|
|
|
| CERT_PASSWORD | The password for the generated certificate | N/A **(required)** |
|
|
| DOTNET_SDK_VERSION | The [SDK](https://mcr.microsoft.com/en-us/artifact/mar/dotnet/sdk/tags) version used to generate the development certificate | 9.0.202 |
|
|
| DOTNET_RUNTIME_VERSION | The [runtime](https://mcr.microsoft.com/en-us/artifact/mar/dotnet/aspnet/tags) version used as a base | 9.0.3 |
|
|
| ALPINE_VERSION | The version of [alpine linux](https://www.alpinelinux.org/) used as a base <br/> Currently you can choose between `3.20` or `3.21` | 3.21 |
|
|
|
|
## Security implications
|
|
|
|
### Webserver and certificates
|
|
|
|
This images uses the system provided by Microsoft to generate a development certificate and uses the [Kestrel](https://learn.microsoft.com/en-us/aspnet/core/fundamentals/servers/?view=aspnetcore-9.0&tabs=windows) webserver.<br/>
|
|
In previous .NET versions it was not recommended to expose Kestrel directly to the internet, now Microsoft claims you can do that if you want so.<br/>
|
|
However you never should use the included development certificate included in this image when doing so.
|
|
|
|
If you want to directly expose the Kestrel webserver use the following environment variables to properly setup a certificate :
|
|
- **ASPNETCORE_Kestrel__Certificates__Default__Path** (the path to the certificate key)
|
|
- **ASPNETCORE_Kestrel__Certificates__Default__KeyPath** (the path to the certificate)
|
|
- **ASPNETCORE_Kestrel__Certificates__Default__Password** (the password for the key file)
|
|
|
|
The certificate included by default (generated through the _dotnet dev-certs_ command) is not really suited for production environments.
|
|
|
|
In practice it's much easier to expose the server through a proxy to the public (hence the recommended method).
|
|
Depending on your use-case you event might consider to use docker networking in order to accomplish proper isolation.
|
|
|
|
### Included certificate
|
|
|
|
The included certificate is generated through the _dotnet dev-certs_ command. This is very convenient and suitable way to generated development certificates through the dotnet SDK.<br/>
|
|
The password used to generate the certificate is randomly generated through the `openssl rand -base64 12` at build time.
|
|
The build agent used for the build is hosted on my own infrastructure but I don't have any access to it (neither do I intend to do so).<br/>
|
|
However if you feel uncomfortable with this fact, feel free to build the image yourself.
|