It modifies the Docker data folder to a new location. It is useful if you want to move the Docker data folder to a different drive or partition.

modify_docker_data_folder.sh

#!/bin/bash

# It modifies the Docker data folder to a new location. It is useful if you want to move the Docker data folder to a different drive or partition.
# Example usage:
# ./modify_docker_data_folder.sh /mnt/docker_data

red='\033[0;31m'
green='\033[0;32m'
yellow='\033[0;33m'
plain='\033[0m'
export PATH=$PATH:/usr/local/bin

# Check if Docker is installed
command -v docker >/dev/null 2>&1
if [[ $? != 0 ]]; then
  echo -e "${red}Docker is not installed. Please install Docker first.${plain}"
  exit 1
fi

# Get the new data directory from the command line argument
new_dir=$1
# Get the current Docker storage directory
current_dir=$(docker info --format='{{json .DockerRootDir}}')
# Remove the quotes from the current directory
current_dir=$(echo $current_dir | tr -d '"')

# If no new data directory is provided, prompt the user for one
if [[ -z "${new_dir}" ]]; then
  read -ep "Enter the absolute path to the new Docker data directory (current: ${current_dir}): " new_dir
fi

# Check if the new data directory is empty
if [[ -z "${new_dir}" ]]; then
  echo -e "${red}You did not enter a new data directory path.${plain}"
  exit 1
fi

# if the new data directory is the same as the current one, exit
if [[ "${new_dir}" == "${current_dir}" ]]; then
  echo -e "${yellow}The new data directory is the same as the current one. Exiting.${plain}"
  exit 0
fi

# if the new data directory exists, exit
if [[ -d "${new_dir}" ]]; then
  echo -e "${red}The new data directory already exists. Exiting.${plain}"
  exit 1
fi

# Stop the Docker service
systemctl stop docker > /dev/null 2>&1
echo -e "${green}Docker service stopped${plain}"

# check and set "data-root" to /etc/docker/daemon.json 
if [[ ! -f /etc/docker/daemon.json ]]; then
  # create /etc/docker/daemon.json
  echo "{\"data-root\": \"${new_dir}\"}" > /etc/docker/daemon.json
elif [[ $(grep -c "data-root" /etc/docker/daemon.json) -eq 0 ]]; then
  # add "data-root" to /etc/docker/daemon.json
  sed -i '1s/{/{\n  "data-root": "'${new_dir}'",/' /etc/docker/daemon.json
else
  echo -e "${yellow}Replacing data-root in /etc/docker/daemon.json${plain}"
  sed -i "s|\"data-root\": \".*\"|\"data-root\": \"${new_dir}\"|g" /etc/docker/daemon.json
fi

# Copy the existing data to the new directory
mkdir -p $new_dir

echo -e "${green}Copying existing data to the new directory${plain}"
rsync -aP $current_dir/* $new_dir > /dev/null 2>&1
echo -e "${green}Copying completed${plain}"


# Reload the service
systemctl daemon-reload

# Start Docker
systemctl start docker > /dev/null 2>&1
echo -e "${green}Docker service started${plain}"

# Wait for Docker to start
sleep 5

# Print the old and new directories
echo -e "Docker data directory has been changed from ${current_dir} to ${new_dir}"

# Check if the storage location has been successfully changed
echo -e "${green}Checking the new Docker data directory${plain} ..."
docker info --format='{{.DockerRootDir}}'
echo -e "${green}Checking completed${plain}"

echo -e "${green}Modify Docker data folder completed${plain}"