Terminal Commands
Open your terminal and type the following commands :
$sudo apt update
Install docker dependencies
$sudo apt install apt-transport-https ca-certificates curl gnupg lsb-release -y
Get the docker PGP key
$curl -fsSL https://download.docker.com/linux/debian/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
In the command below be sure to replace with whatever version of debian you are running, i.e., buster, bullseye, stretch
$echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/debian buster stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
Perform an update for installed binaries.
$sudo apt update
$sudo apt -y install docker-ce docker-ce-cli containerd.io
Add Username to Docker Group
Sometimes you do not want to use docker with sudo account. You can add another username to docker group so that sudo command is not necessary for the docker user
$sudo usermod -aG docker your_username
That's it. You should be able to run docker commands in your system.
Docker
This part was first created Monday, March 7, 2022. From my Securanalyst.blogspot.com
$docker images
$docker search [image]
Downloading an image
$docker pull [image]
// example install an ubuntu image
$docker pull ubuntu
Alternatively
$docker run [image]
// run the image
$docker run ubuntu
Useful information about containers
To get a list of all running containers
$docker ps
This will exit, because it is not set to run in the background capabilities. To make this run in the background run
$docker run -it -d ubuntu
// where the flag -it stands for interactive terminal
// where the flag -d activates daemon / service mode
To get a list of all exited containers
$docker ps -a
You can also type the first few unique characters of the id
$docker attach [CONTAINER ID]
Image persistance
To make this image persist press the key sequence below while not letting go off Cntrl key:
Ctrl + p
Ctrl + q
Even when you exit (Ctrl+d), this container will persist.
Run bash
To run a bash or any other pre-inbuilt ubuntu command inside the ubuntu container image
$docker run -it ubuntu /bin/bash
This will open up a bash shell similar to ubuntu, with ubuntu capabilities quite similar to the wsl, which is absolutely awesome.
To exit, Ctrl + d
Accessing Apps
$docker run -it -d -p 8080:80 nginx
This ports are not accessible (by default) outside the container for security purposes. Access the nginx on localhost with the port on the browser to stop the process
$docker stop [container_id]
Run web app
To run web applications on container, that we want to run continuously.
$docker run -it -d --restart unless-stopped -p 8080:80 nginx
To remove a container:
$docker rm [container_id]
Saving changes to image
To save changes to image like ubuntu
$docker run -it ubuntu
$apt udpate
$apt dist-upgrade
$apt install apache2
$/etc/init.d/apache2 status
$/etc/init.d/apache2 start
$apt install vim-nox
Commit changes
Disconnect using: Ctrl + p Ctrl + q
$ docker commit [container_id] [preferred name of image:version number]
// For example
$docker commit [container-id] docker build -t lltv/apache:1.0 .
The period (.) at the end is to create the image in current directory
Automate the process by creating a Dockerfile
First, create and open file called "Dockerfile"
$touch Dockerfile
$nano Dockerfile
Then you can paste the following (Edit where necessary):
FROM ubuntu
MAINTAINER your_username <your_email@example.com>
# Skip prompts
ARG DEBIAN_FRONTEND=noninteractive
# Update packages
RUN apt update; apt dist-upgrade -y
# Install packages
RUN apt install -y apache2 vim-nox
# Set entrypoint
ENTRYPOINT apache2ctl -D FOREGROUND
Then save and exit nano.
The next command must be run from the same location that contains the Dockerfile
$docker build -t lltv/apache:1.1 .
// Important! note the period (.) at the end
to remove an image
$docker images
$docker rmi [image id]
If you encounter any error; refer to the container id and remove it using:
docker rm [container_id]