Dockerfile

# Base Ubuntu
FROM ubuntu:24.04

WORKDIR /mc


# download PaperMC
ADD https://fill-data.papermc.io/v1/objects/aec002e77c7566e49494fdf05430b96078ffd1d7430e652d4f338fef951e7a10/paper-1.21.9-59.jar paper.jar

# eula + offline mode
RUN echo "eula=true" > eula.txt && \
    echo "online-mode=false" >> server.properties

# download & install cloudflared deb
ADD https://github.com/cloudflare/cloudflared/releases/download/2025.11.1/cloudflared-linux-386.deb /tmp/cloudflared.deb
RUN dpkg -i /tmp/cloudflared.deb || apt-get install -f -y

# expose MC port
EXPOSE 25565

ENV INIT_MEMORY=2G
ENV MAX_MEMORY=4G

# start MC + cloudflared tunnel
CMD sh -c "cloudflared tunnel --url tcp://localhost:25565 & java -Xms${INIT_MEMORY} -Xmx${MAX_MEMORY} -jar paper.jar nogui"