Building and Pushing an ARM Image for Ubuntu server to Docker Hub

Prerequisites

Before we begin, make sure you have the following:

An Ubuntu server (or any other Linux server)
Docker installed on the server
Docker Hub account

Dockerfile

Here's the Dockerfile that we'll be using to create our ARM image:

Dockerfile

# Use an ARM64 base image for Ubuntu 20.04
FROM arm64v8/ubuntu:20.04

# Set environment variables for non-interactive installation
ENV DEBIAN_FRONTEND=noninteractive

# Set the timezone to avoid tzdata prompt during installation
ENV TZ=America/New_York
RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone

# Set the environment variables for the Maven version and directories
ARG MAVEN_VERSION=3.8.1
ARG USER_HOME_DIR="/root"
ARG MAVEN_HOME="/usr/share/maven"
ENV MAVEN_HOME=${MAVEN_HOME}
ENV MAVEN_CONFIG="${USER_HOME_DIR}/.m2"
ENV PATH=${MAVEN_HOME}/bin:${PATH}

# Install dependencies: OpenJDK 11, curl, tar, git, and Docker
RUN apt-get update && \
    apt-get install -y openjdk-11-jdk curl tar git docker.io tzdata && \
    rm -rf /var/lib/apt/lists/*

# Install Maven
ARG BASE_URL=https://archive.apache.org/dist/maven/maven-3/${MAVEN_VERSION}/binaries
RUN curl -fsSL ${BASE_URL}/apache-maven-${MAVEN_VERSION}-bin.tar.gz -o /tmp/apache-maven.tar.gz && \
    mkdir -p ${MAVEN_HOME} && \
    tar -xzf /tmp/apache-maven.tar.gz -C ${MAVEN_HOME} --strip-components=1 && \
    rm -f /tmp/apache-maven.tar.gz && \
    ln -s ${MAVEN_HOME}/bin/mvn /usr/bin/mvn

# Set the working directory
WORKDIR /workspace

# Copy entrypoint script if needed (optional)
# COPY mvn-entrypoint.sh /usr/local/bin/mvn-entrypoint.sh
# RUN chmod +x /usr/local/bin/mvn-entrypoint.sh

# Set the entrypoint for the Docker container (optional, if you have an entrypoint script)
# ENTRYPOINT ["/usr/local/bin/mvn-entrypoint.sh"]

# Default command to run Maven version
CMD ["mvn", "--version"]

mvn-entrypoint.sh

#! /bin/sh -eu

# Copy files from /usr/share/maven/ref into ${MAVEN_CONFIG}
# So the initial ~/.m2 is set with expected content.
# Don't override, as this is just a reference setup

copy_reference_files() {
  local log="$MAVEN_CONFIG/copy_reference_file.log"
  local ref="/usr/share/maven/ref"

  if mkdir -p "${MAVEN_CONFIG}/repository" && touch "${log}" > /dev/null 2>&1 ; then
      cd "${ref}"
      local reflink=""
      if cp --help 2>&1 | grep -q reflink ; then
          reflink="--reflink=auto"
      fi
      if [ -n "$(find "${MAVEN_CONFIG}/repository" -maxdepth 0 -type d -empty 2>/dev/null)" ] ; then
          # destination is empty...
          echo "--- Copying all files to ${MAVEN_CONFIG} at $(date)" >> "${log}"
          cp -rv ${reflink} . "${MAVEN_CONFIG}" >> "${log}"
      else
          # destination is non-empty, copy file-by-file
          echo "--- Copying individual files to ${MAVEN_CONFIG} at $(date)" >> "${log}"
          find . -type f -exec sh -eu -c '
              log="${1}"
              shift
              reflink="${1}"
              shift
              for f in "$@" ; do
                  if [ ! -e "${MAVEN_CONFIG}/${f}" ] || [ -e "${f}.override}" ] ; then
                      mkdir -p "${MAVEN_CONFIG}/$(dirname "${f}")"
                      cp -rv ${reflink} "${f}" "${MAVEN_CONFIG}/${f}" >> "${log}"
                  fi
              done
          ' _ "${log}" "${reflink}" {} +
      fi
      echo >> "${log}"
  else
    echo "Cannot write to ${log}. Wrong volume permissions? Carrying on ..."
  fi
}

owd="$(pwd)"
copy_reference_files
unset MAVEN_CONFIG

cd "${owd}"
unset owd

exec "$@"

Steps to Build and Push the Image

Before you begin, make sure both mvn-entrypoint.sh and Dockerfile are in the same directory.

1. Build the Docker Image First, navigate to the directory containing your Dockerfile and build the Docker image using the following command:

docker build -t your-dockerhub-username/ubuntu-arm:latest .

1. Tag the Docker Image Tag the Docker image with your Docker Hub repository name:

docker tag your-dockerhub-username/ubuntu-arm:latest your-dockerhub-username/ubuntu-arm:1.0

1. Log in to your Docker Hub account:

docker login

1. Push the Docker image to Docker Hub:

docker push your-dockerhub-username/ubuntu-arm:1.0

1. Verify the Docker Image

You can verify that the Docker image has been pushed to Docker Hub by visiting your Docker Hub repository.

docker pull your-dockerhub-username/ubuntu-arm:1.0

Conclusion

That's it! You have successfully created an ARM image for Ubuntu, built it on an Ubuntu server, and pushed it to Docker Hub. This process can be extremely useful for deploying applications on ARM-based devices. Feel free to reach out if you have any questions or need further assistance.