crun/docs/mono-example.md

mono windows dotnet handler

• Make sure oci config contains handler for mono or image contains annotation run.oci.handler=dotnet.
• Entrypoint must point to a valid .exe (windows .NET compatible executable).

...
"annotations": {
 "run.oci.handler": "dotnet"
},
...

Examples

Compile and run mono compatible dotnet executables inside containers natively

• Following example is using mono to compile a cross platform executable but you can also use visual studio or any other build tools on windows.
• Add relevant function to hello.cs for this example we will be using a print.

 using System;
 using System.Runtime.CompilerServices;

 class MonoEmbed {
   static int Main ()
   {
   	System.Console.WriteLine("hello");
   	return 0;
   }
 }

• Compile a new .exe using mcs -out:hello.exe hello.cs if you have mono or you can VisualStudio or dotnet build as specified here: https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-build
• Create relevant image and use your container manager. But for this example we will be running directly using crun and plub config manually.

$ crun run container-with-mono
hello

Running OCI mono compat images with buildah and podman

• Compile your .exe module using instructions from step one.
• Prepare a Containerfile with your .exe.

FROM scratch
COPY hello.exe /
CMD ["/hello.exe"]

• Build wasm image using buildah with annotation run.oci.handler=dotnet

$ buildah build --annotation "run.oci.handler=dotnet" -t my-windows-executable .

• Make sure your podman points to oci runtime crun build with mono support.
• Run image using podman

$ podman run --userns=keep-id my-windows-executable:latest
hello

Known-Issues

• Crun-mono containers needs user namespace for containers so with podman use --userns=auto or --userns=keep-id.