Docker

Create a Dockerfile

• Resources
  • https://docs.docker.com/get-started/docker-concepts/building-images/writing-a-dockerfile/
  • https://freedium.cfd/https://medium.com/@anshita.bhasin/a-step-by-step-guide-to-create-dockerfile-9e3744d38d11

Push image to Docker Hub

1. Log in to Docker Hub
   • Make sure you have a Docker Hub account. If not, create one at Docker Hub.
   • Log in using the Docker CLI:

     docker login

   • Enter your username and password when prompted.

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2. Tag the Image
   • Docker images must have a tag that includes your Docker Hub username to push to your repository.
   • For example, if your Docker Hub username is yourusername and you want to push ocr-docker:v1, tag the image:

     docker tag ocr-docker:v1 yourusername/ocr-docker:v1

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3. Push the Image
   • Push the tagged image to Docker Hub:

     docker push yourusername/ocr-docker:v1

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4. Verify the Image on Docker Hub
   • Go to your Docker Hub account and check under Repositories to confirm that the image was successfully pushed.

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Using the Image

• Once the image is on Docker Hub, anyone with Docker installed can pull and use it:

  docker pull yourusername/ocr-docker:v1
  docker run yourusername/ocr-docker:v1

Multi-platform support

An Updated Guide to Docker and ROS2- Build arguments

Notice that we’ve set up the argument, ARG ROS_DISTRO=humble, so it can be changed for other distributions of ROS 2 (Iron, Rolling, etc.). Rather than creating multiple Dockerfiles for different configurations, you should try using build arguments like these as much as possible

ARG ROS_DISTRO=humble
 
########################################
# Base Image for TurtleBot3 Simulation #
########################################
FROM osrf/ros:${ROS_DISTRO}-desktop as base
ENV ROS_DISTRO=${ROS_DISTRO}
SHELL ["/bin/bash", "-c"]
 
# Create Colcon workspace with external dependencies
RUN mkdir -p /turtlebot3_ws/src
WORKDIR /turtlebot3_ws/src
COPY dependencies.repos .
RUN vcs import < dependencies.repos
 
# Build the base Colcon workspace, installing dependencies first.
WORKDIR /turtlebot3_ws
RUN source /opt/ros/${ROS_DISTRO}/setup.bash \
 && apt-get update -y \
 && rosdep install --from-paths src --ignore-src --rosdistro ${ROS_DISTRO} -y \
 && colcon build --symlink-install
ENV TURTLEBOT3_MODEL=waffle_pi

To build your image with a specific argument — let’s say you want to use ROS 2 Rolling instead — you could do the following… provided that all your references to ${ROS_DISTRO} actually have something that correctly resolves to the rolling distribution.

docker build -f docker/Dockerfile \
   --build-arg="ROS_DISTRO=rolling" \
   --target base -t turtlebot3_behavior:base .

Faster Multi-Platform Builds: Dockerfile Cross-Compilation Guide

• In Docker, TARGETARCH is a built-in build argument that represents the target architecture (e.g., linux/amd64, linux/arm64, etc.) for the image you are building. This is particularly useful when building multi-architecture images using Docker’s Buildx feature. Example:

# syntax=docker/dockerfile:1
FROM --platform=$BUILDPLATFORM alpine:latest
 
ARG TARGETARCH
 
RUN echo "Building for architecture: $TARGETARCH"
 
# Copy binary depending on the target architecture
COPY --from=builder /binaries/$TARGETARCH/mybinary /usr/local/bin/mybinary

• Multi-architecture builds: To build images for multiple architectures simultaneously, use the docker buildx build command with the —platform flag. This will automatically set the TARGETARCH argument for each build.

• Create a builder image as building multi-platform images is currently only supported when using BuildKit with docker-container and kubernetes driversbash

docker buildx create --use

cool_sanderson

docker buildx build --platform linux/amd64,linux/arm64 -t myimage:latest .