Technitium on Alpine

[stratself]

I've got a working PoC build on Alpine Linux (I think). After following the build instructions, the only difference is to replace apt stuff with apk (Alpine's package keeper software):

# install dependencies
doas apk add libmsquic dotnet9-sdk git curl

# the rest can be done as normal
git clone --depth 1 https://github.com/TechnitiumSoftware/TechnitiumLibrary.git TechnitiumLibrary
git clone --depth 1 https://github.com/TechnitiumSoftware/DnsServer.git DnsServer

dotnet build TechnitiumLibrary/TechnitiumLibrary.ByteTree/TechnitiumLibrary.ByteTree.csproj -c Release
dotnet build TechnitiumLibrary/TechnitiumLibrary.Net/TechnitiumLibrary.Net.csproj -c Release
dotnet build TechnitiumLibrary/TechnitiumLibrary.Security.OTP/TechnitiumLibrary.Security.OTP.csproj -c Release

dotnet publish DnsServer/DnsServerApp/DnsServerApp.csproj -c Release

libmsquic and dotnet9-sdk are available on the edge and v3.23 releases, so no need to configure any external repositories. After building you can launch the binary from ./DnsServer/DnsServerApp/bin/Release/DnsServerApp

On a Raspberry Pi 4 it compiles under 2 minutes, so the process is quite fast. I was able to test that all the Optional Protocols including DoQ work fine.

Docker

I'm doing this as part of building an Alpine-based Technitium container for personal use. The container-based build process can be done as below:

Dockerfile

FROM alpine:edge as build
WORKDIR /build
RUN <<HEREDOC

    # Add dependencies
    apk add libmsquic dotnet9-sdk git curl

    # Clone the repositories
    git clone --depth 1 https://github.com/TechnitiumSoftware/TechnitiumLibrary.git TechnitiumLibrary
    git clone --depth 1 https://github.com/TechnitiumSoftware/DnsServer.git DnsServer

    # Build TechnitiumLibraries
    dotnet build TechnitiumLibrary/TechnitiumLibrary.ByteTree/TechnitiumLibrary.ByteTree.csproj -c Release
    dotnet build TechnitiumLibrary/TechnitiumLibrary.Net/TechnitiumLibrary.Net.csproj -c Release
    dotnet build TechnitiumLibrary/TechnitiumLibrary.Security.OTP/TechnitiumLibrary.Security.OTP.csproj -c Release
    
    # Compile DnsServer
    dotnet publish DnsServer/DnsServerApp/DnsServerApp.csproj -c Release
HEREDOC

FROM alpine:edge

# Add runtime packages
RUN apk add -U --no-cache aspnetcore9-runtime libmsquic doggo

WORKDIR /opt/technitium/dns
COPY --link --from=build /build/DnsServer/DnsServerApp/bin/Release/publish /opt/technitium/dns

ENTRYPOINT ["/usr/bin/dotnet", "/opt/technitium/dns/DnsServerApp.dll"]
CMD ["/etc/dns"]

LABEL org.opencontainers.image.title="Technitium DNS Server (Alpine fork)"

For the runtime, only aspnetcore9-runtime is needed to get Technitium started. I'm using doggo instead of dnsutils for DNS troubleshooting, but you can replace that package with what you want too.

The resulting image on x86_64 is 166MB, which is 100MB smaller than Technitium's official image. I guess using something like distroless could shrink the image size even more, but this is good for now.

I think the normal Dockerfile can use dotnet/aspnet:9.0-alpine3.23 as a smaller alternative too, but seeing from past developments it can bring in more maintenance issues. There was #1046 which implemented support for chisel, but was later reverted in #1053 due to some libmsquic difficulties.

OpenRC

PR #1461 includes an openrc.service file to use with the OpenRC service manager. I don't have any experience with it though

What else

I believe building (and publishing) an actual APKBUILD file for inclusion in Alpine Linux repos is doable, though I don't have any experience with them either