Docker Assignment 1

This is a method of software deployment process that bundles application's code and its dependencies required for the application to run on any infrastructure both in the cloud and on-premise.

Some major benefit of using containerization method in deployment of an application include the following:

• Portability
• Scalability
• Fault tolerance and
• Agility

Docker is an open source containerization tool launched in 2008 that helps build, test and deploy containerized application/software faster and efficiently.

To install docker on an environment, the requirement is to have 64-bit version of one of these Ubuntu versions

• a. Ubuntu Mantic 23.10
• b. Ubuntu Jammy 22.04 (LTS)
• c. Ubuntu Focal 20.04 (LTS)

For this demonstration i will be making use of Amazon Web Service (AWS) EC2 Ubuntu Jammy 22.04 (LTS) using the apt repository.

• After the launch of an EC2 Ubuntu 22.04 (LTS) on AWS, we need to login into the instance using SSh commnd or the use of Putty.

  ssh -i <key_name> remote_username@remote_host
  

• Installing docker for the first time on a new machine requires the need of setting up the docker repository. After which wee can install and update docker from the repository

  • Set up Docker's apt repository by running the below command

        # Add Docker's official GPG key:
        sudo apt-get update
        sudo apt-get install ca-certificates curl
        sudo install -m 0755 -d /etc/apt/keyrings
        sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
        sudo chmod a+r /etc/apt/keyrings/docker.asc
    
        # Add the repository to Apt sources:
        echo \
        "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu \
        $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | \
        sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
        sudo apt-get update                
    

  • Install the Docker packages. To install the latest version of docker run:

        sudo apt-get install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin -y
    

  • Now, let us verify if the docker was installed and to get the docker version installed in the ubuntu

    • Additionally let's have the root privilege to run our docker commands

          sudo -i
      

    • For the version detals run:

          docker -V
      

      

    • To get Docker service status run:

          systemctl status docker
      

      

• Running ubuntu and alpine docker images in forground

  • Ubuntu image

        # Run ubuntu container in foreground
        docker run --rm -it ubuntu
    

    

  • alpine image

        # Run alpine container in foreground
        docker run --rm -it alpine
    

    

• Running ubuntu and alpine docker images in background

  • Ubuntu image

        # Run alpine container in background
        docker run -d --name alpine_container alpine
    

  • alpine image

        # Run ubuntu container in background
        docker run -d --name ubuntu_container ubuntu
    

    

• Installing Python3 and npm in both the alpine and ubuntu containers

  • ubuntu container: Run the following command

        # Start the container
        docker run -dit ubuntu
    
        #   Ge the container ID
        docker ps
    
        # Attach to the container's shell
        docker exec -it <container-Id> /bin/bash
    
        # Update package index
        apt update
    
        # Install Python 3 and npm
        apt install -y python3 npm
    
        # verify if python3 and npm are installed
        python3 -V
        npm –version
    

    

  • alpine container: Run the following command

        # Start the container
        docker run -dit alpine
    
        # Get the container ID
        docker ps
    
        # Attach to the container's shell
        docker exec -it <container-Id> sh
    
        # Update package index
        apk update
    
        # Install Python 3 and npm
        apk add python3 npm
    
        # Verify if Python 3 and npm are installed
        python3 -V
        npm --version
    

    

• To view images associated with the docker containers, we run

      docker images
  

  

• Some important docker command includes:

1. docker run: This command is used to create and start a new container from an image.

   Example:

   docker run -it --rm ubuntu

2. docker ps: This command lists all running containers.

   Example:

   docker ps

3. docker images: This command lists all Docker images available on your system.

   Example:

   docker images

4. docker build: This command is used to build a Docker image from a Dockerfile.

   Example:

   docker build -t my_image .

5. docker stop: This command is used to stop one or more running containers.

   Example:

   docker stop my_container

6. docker start: This command is used to start one or more stopped containers.

   Example:

   docker start my_container

7. docker exec: This command is used to execute a command inside a running container.

   Example:

   docker exec -it my_container bash

8. docker rm: This command is used to remove one or more stopped containers.

   Example:

   docker rm my_container

9. docker rmi: This command is used to remove one or more Docker images.

   Example:

   docker rmi my_image

10. docker-compose: This command is used to define and run multi-container Docker applications.

    Example:

    docker-compose up -d