How do I go about installing a certificate on a nanoserver-1709 based image on a docker container? - asp.net

Question

I've been looking around this image for any cert managers but I can't find anything that will help me install a .cer certificate. The 1709 nanoserver image doesn't come with powershell so in order to use that I would have to do a multi-staged build with the microsoft/windowsservercore image but I'm not quite sure how I'd go about doing this, I can't seem to find anything through google that will help.
If anybody knows a way to install the cert with or withour a multi-stage build that would be very appreciated.
For those interested, here's my docker-compose.yml and Dockerfile
docker-compose.yml
version: '3'
services:
myapp:
image: myapp
ports:
- "5000:80"
build:
context: .
dockerfile: MyApp\Dockerfile
container_name: "myapp"
hostname: "myapp"
depends_on:
- db
db:
image: "microsoft/mssql-server-windows-express"
environment:
SA_PASSWORD: ""
ACCEPT_EULA: "Y"
container_name: "myapp"
hostname: "myapp"
Dockerfile
FROM microsoft/aspnetcore:2.0-nanoserver-1709 AS base
WORKDIR /app
EXPOSE 80
FROM microsoft/aspnetcore-build:2.0-nanoserver-1709 AS build
WORKDIR /src
COPY MyApp.sln ./
COPY MyApp/MyApp.csproj MyApp/
RUN dotnet restore -nowarn:msb3202,nu1503
COPY . .
WORKDIR /src/MyApp
RUN dotnet restore
RUN dotnet ef database update
RUN dotnet build -c Release -o /app
FROM build AS publish
RUN dotnet publish -c Release -o /app
FROM base AS final
WORKDIR /app
COPY --from=publish /app .
ENTRYPOINT ["dotnet", "MyApp.dll"]
Thanks!

Answer 1

On some images, there is a tool called certoc.exe that allows you to import a certificate (usage: certoc.exe -addstore root my_root_certificate.cer).
This tool is not present on the 1709 images, but is present on images such as microsoft/nanoserver:sac2016.
To sum-up, the best way I found to deal with that is to change the Dockerfile to contain something like:
FROM microsoft/nanoserver:sac2016 as tool
COPY --from=tool /Windows/System32/certoc.exe .
USER ContainerAdministrator
RUN certoc.exe -addstore root my_root_certificate.cer
Complete example available here: https://pvlerick.github.io/2018/11/how-to-run-an-https-asp.net-core-app-using-test-certificates-in-nanoserver-1709-1803-with-docker
A huge thanks to Joshua Chini here: https://joshuachini.com/2018/02/08/how-to-import-an-enterprise-certificate-into-a-windows-container/