Docker Containers

Docker is a software platform for building and running applications inside isolated environments called containers. It packages an application together with its dependencies into a lightweight, portable unit that can run consistently across environments without requiring major configuration changes.

A container is a self-contained unit that bundles an application's source code and dependencies. It can be started or moved between environments quickly and efficiently. Unlike a virtual machine, which requires a separate operating system for each instance, a container shares the host kernel and includes only what the application needs.

• Portability: Run the same containerized application across multiple environments, including cloud platforms, with minimal configuration changes.
• Efficient resource usage: Docker containers are lighter than virtual machines because they do not require a dedicated hypervisor and operating system for each workload.

• Operating system compatibility: Docker can run on non-Linux systems, but its performance and behavior may differ from a native Linux environment.
• Orchestration complexity: Managing larger deployments requires additional tooling, such as Docker Swarm or Kubernetes, which introduces a steeper learning curve.

• Update the package index and install curl and certificate packages.

  bash

  sudo apt-get update
  sudo apt-get install ca-certificates curl -y
  

• Configure Docker's GPG key so packages can be verified against the official repository.

  bash

  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 official Docker repository.

  bash

  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
  

• Install Docker Engine and its supporting components.

  bash

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

• Allow the current non-root user to run Docker commands.

  bash

  sudo usermod -aG docker $USER
  sudo chmod 666 /var/run/docker.sock
  docker version