Install Docker on Debian

Set up the repository
Update the apt package index and install packages to allow apt to use a repository over HTTPS:

$ sudo apt-get update
$ sudo apt-get install ca-certificates curl gnupg lsb-release

Add Docker’s official GPG key:

$ curl -fsSL https://download.docker.com/linux/debian/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

Use the following command to set up the stable repository.

echo \
 "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/debian \
  $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Install Docker Engine

Update the apt package index, and install the latest version of Docker Engine and containerd, or go to the next step to install a specific version:

$ sudo apt-get update
$ sudo apt-get install docker-ce docker-ce-cli containerd.io

Verify that Docker Engine is installed correctly by running the hello-world image.

$ sudo docker run hello-world

Configure Docker to start on boot

$ sudo systemctl enable docker.service
$ sudo systemctl enable containerd.service

Manage Docker as a non-root user
Create the docker group.

sudo groupadd docker

Add your user to the docker group.

sudo usermod -aG docker $USER

Log out and log back in so that your group membership is re-evaluated. If testing on a virtual machine, it may be necessary to restart the virtual machine for changes to take effect. On a desktop Linux environment such as X Windows, log out of your session completely and then log back in.

On Linux, you can also run the following command to activate the changes to groups:

newgrp docker 

Verify that you can run docker commands without sudo.

$ docker run hello-world

This command downloads a test image and runs it in a container. When the container runs, it prints a message and exits.

Configuring remote access with systemd unit file

Use the command sudo systemctl edit docker.service to open an override file for docker.service in a text editor. Add or modify the following lines, substituting your own values.

[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H fd:// -H tcp://127.0.0.1:2375

Save the file. Reload the systemctl configuration.

 sudo systemctl daemon-reload

Restart Docker.

 sudo systemctl restart docker.service

Check to see whether the change was honored by reviewing the output of netstat to confirm dockerd is listening on the configured port.

$ sudo netstat -lntp | grep dockerd

Configuring remote access with daemon.json

Set the hosts array in the /etc/docker/daemon.json to connect to the UNIX socket and an IP address, as follows:

    {
      "hosts": ["unix:///var/run/docker.sock", "tcp://127.0.0.1:2375"]
    }

Restart Docker. Check to see whether the change was honored by reviewing the output of netstat to confirm dockerd is listening on the configured port.

 sudo netstat -lntp | grep dockerd

Ref:
https://docs.docker.com/engine/install/debian/
https://docs.docker.com/engine/install/linux-postinstall/