Build .NET containers on M1 laptop and deploy them to cloud

After failing to deploy a Docker container built on M1 laptop, I finally found about the official example dotnet-docker.

FROM --platform=$BUILDPLATFORM mcr.microsoft.com/dotnet/sdk:8.0 AS build
ARG TARGETARCH
WORKDIR /source

COPY app.csproj app.csproj
RUN dotnet restore -a $TARGETARCH

COPY . .
RUN dotnet publish -a $TARGETARCH --no-restore -o /app

FROM mcr.microsoft.com/dotnet/aspnet:8.0
WORKDIR /app
COPY --from=build /app .
ENTRYPOINT [ "dotnet", "app.dll" ]

To build it, run docker build --pull -t app --platform linux/amd64 .. This can be pushed to regular registry (I use DigitalOcean) and will work inside amd64 clusters.

A cool command found in that repo is:

docker inspect APP-TAG -f "{{.Os}}\{{.Architecture}}"

That will print out the architecture of the container you've built.