Docker Self-help

Compilation of all Docker info that I have come to rely on. To serve as a quick reference when troubleshooting issues with Docker.

Contents

• Setup Docker
• Build Docker Image
• Run Docker Container from Image
• Access a Running Container
• Monitoring

Setup Docker

Click to expand

Ubuntu

1. Install Docker Engine.

2. Remove need for sudo for docker.

3. Install NVIDIA Container Toolkit for GPU support.

Windows

*Recommend to use WSL 2.

1. Install Docker Desktop.

2. Enable 'Use the WSL 2 based engine' in Docker Desktop >> Settings >> General.

3. 'Enable integration with my default WSL distro' and additional distros in Docker Desktop >> Settings >> Resources >> WSL Integration.

4. Remove need for sudo for docker.

   In WSL2 shell,

   sudo groupadd docker 
   sudo usermod -aG docker $USER
   

5. [OPTIONAL] Change docker storage location in Windows. Reference: stackoverflow.

Build Docker Image

Requires Dockerfile.

Docker Build

docker build -f <path to dockerfile> -t <docker image name> . 

Docker Build Flags

• List of docker build flags: Official Documentation.

Dockerfile

• Include following snippet in Dockerfile to avoid ownership and permission issues for files/folders created within the docker container.

  ARG USERNAME=user
  ARG USER_UID=1000
  ARG USER_GID=$USER_UID
  
  # Create the user
  RUN groupadd --gid $USER_GID $USERNAME \
  && useradd --uid $USER_UID --gid $USER_GID -m $USERNAME \
  #
  # [Optional] Add sudo support. Omit if you don't need to install software after connecting.
  && echo $USERNAME ALL=\(root\) NOPASSWD:ALL > /etc/sudoers.d/$USERNAME \
  && chmod 0440 /etc/sudoers.d/$USERNAME
  

Run Docker Container from Image

Requires docker image.

Docker Run

docker run -it <FLAGS> <image name>

*Assumes user interaction with the container is required after starting the container.

Running GUI apps from container

Reference: stackoverflow

From WSL (i.e. Ubuntu Distro in Windows) - Works in Ubuntu app terminal or Powershell after ubuntu command.

docker run -it \
-v /tmp/.X11-unix:/tmp/.X11-unix -v /mnt/wslg:/mnt/wslg -e DISPLAY=:0 -e WAYLAND_DISPLAY=wayland-0 -e XDG_RUNTIME_DIR=/mnt/wslg/runtime-dir -e PULSE_SERVER=/mnt/wslg/PulseServer \
<image name>

From Windows

Not tested.

Docker Run Flags

• List of docker run flags: Official Documentation.

• Enable GPU support.

  --gpus=all
  

• Specify name for running container. Makes it easier to docker exec into the desired container.

  --name <container name>
  

• Automatically remove container after it is stopped.

  --rm
  

• Bind mount a volume from host to the container.

  -v <path>/<to>/<host>/<volume>:<path>/<to>/<container>/<volume>
  

  Alternatively,

  --mount type=bind,source=<host PATH>,target=<container PATH>
  

• Volume mount a volume (managed only by Docker) from host to container. Recommended for sharing data between containers.

  --mount source=<VOLUME NAME>,target=<container PATH>
  

• Connect the container to a network. (Official Documentation)

  --network <network name>
  

  • Default if none specified is --network bridge. Containers are on bridge network, isolated from host.

  • --network host for host and containers to be connected.

  • --network none to isolate the container from all other containers and the host.

Access a Running Container

Docker Exec

• Launch bash in a new terminal in a running container. "Enter" a running container.

  docker exec -it <container name> bash
  

Monitoring

Click to expand