Docker

Docker is a tool designed to make it easier to create, deploy, and run applications by using containers.

Containers allow a developer to package up an application with all of the parts it needs, such as libraries and other dependencies, and ship it all out as one package. By doing so, thanks to the container, the developer can rest assured that the application will run on any other Linux machine regardless of any customized settings that machine might have that could differ from the machine used for writing and testing the code.

Docker commands

• docker info - show docker system info

Commands related to images

• docker build -f Dockerfile.nav -t nav_cont:latest --build-arg BASE_IMAGE="nvidia_x86" .. - build image passing build-time variable BASE_IMAGE to docker file

Note

Build-time variable ARG BASE_IMAGE in a docker file is accessable only during build time

• docker build --no-cache -t nav_cont:latest .. - rebuild image without cache (useful when you want to rebuild image with new dependencies)

• docker pull <image name> - pull an image from a registry (e.g. Docker Hub). When is called after image already pulled, it will pull the latest version of the image.

• docker history <image name> - show the history of an image (layers, size, etc)

Commands related to containers

Run docker containers with GUI

1. xhost +local:root OR xhost + - allow any user to connect to your X server (This is not recommended for security reasons) To disable access, run xhost -

2. docker run -it --rm --privileged --network host --runtime=nvidia --gpus all --env="DISPLAY" --env="QT_X11_NO_MITSHM=1" --volume="/tmp/.X11-unix:/tmp/.X11-unix:rw" nav_cont:latest

   • --rm - automatically remove the container when it exits

   • --privileged flag gives all capabilities to the container (i.e. device access)

   • --gpus flag when you start a container to access GPU resources. Specify how many GPUs to use (all - use all GPUs)

   • env="DISPLAY" - pass the DISPLAY environment variable to the container

   • --volume="/tmp/.X11-unix:/tmp/.X11-unix:rw" this volume is needed to share the X11 socket with the container. Read-write mode (i.e. the container can write as well as read files on the host)

Note

If a container was started in attached mode (docker run -it), you can detach from the container without stopping it by pressing Ctrl + P + Q

Some more useful commands

• docker ps -a - list all containers (running and stopped)

• docker container ls -a - list all containers (running and stopped) it is alias for docker ps -a

• docker compose ps - list containers for a Compose project, with current status and exposed ports (NB! should be run in the same directory where docker-compose.yml is located)

• docker exec -it <container-name/ID> bash - run bash in a running container

Inspect (containers, networks, images, volumes)

• docker inspect <container name> or <id> - show container info (IP address, etc)

• docker inspect <network name> or <id> - show network info

• docker inspect <image name> or <id> - show image info

• docker inspect <volume name> or <id> - show volume info

Free up disk space

• docker system df - show docker disk usage

• docker builder du - show disk usage by build cache

• docker system prune - cleans up dangling resources (unused data such as stopped containers, dangling images, networks, and more)

• docker system prune -a -a removes all unused images (those that are not associated with any container) not just the dangling ones. NB! all images will be removed

• docker builder prune - remove build cache

To capture docker build logs to a file

docker build -f Dockerfile.bfb_camera_d435i -t bfb_camera_d435i:latest ../.. 2>&1 | tee build.log 2>&1 redirects stderr to stdout, and then | tee build.log pipes stdout to tee, which writes it to build.log and also displays it on the screen.

Docker compose

Create, start, stop and remove containers

• docker compose -f docker-compose_lenovo.yml up

• docker compose up

• docker compose up --build (Build images before starting containers.)

• docker compose start- start the stopped containers, can’t create new ones

• docker compose down - stop and remove containers, networks, images, and volumes

Docker Installation

1. Docker Intallation Guide

2. After installation, add your user to the docker group to avoid using sudo when you use the docker command: sudo usermod -aG docker $USER

Acess Nvidia GPUs in Containers (GPU-accelerated containers)

NVIDIA Container Toolkit enables users to build and run GPU-accelerated containers. The toolkit includes a container runtime library and utilities to automatically configure containers to leverage NVIDIA GPUs.

Official documentation

Note

This installation guide is for Linux only. In Windows GPU support is included in Docker Desktop. Dockerdocs

1. Install Nvidia Container Toolkit: Nvidia Container Toolkit Installation Guide

2. Restart Docker: sudo systemctl restart docker

3. Test Nvidia Container Toolkit: docker run -it --rm --gpus all ubuntu nvidia-smi

4. Run your container with GPU support:

   docker run -it --rm --runtime=nvidia \
   -e DISPLAY \
   -e NVIDIA_VISIBLE_DEVICES=all \
   -e NVIDIA_DRIVER_CAPABILITIES=all \
   -v /tmp/.X11-unix:/tmp/.X11-unix:rw \
   <image name>
   

• Turn on GPU access with Docker Compose (Docker documentation)

• Specialized Configurations with Docker (NVIDIA docs)

Buildx

plugin that alllows to build images for different architectures (e.g. amd64, arm64, etc.) on a single machine.

• docker info | grep -i buildx - check if buildx plugin is installed

• sudo apt update && sudo apt install docker-buildx-plugin - install buildx plugin