Welcome to Containerize: A Docker Introduction

Introduction to Docker

What is Docker?

• Docker revolutionizes software packaging and delivery by isolating applications into containers. Each container is a self-contained, lightweight unit with its own environment.
• These containers are highly portable and can be seamlessly moved between systems thanks to Docker's orchestration capabilities.
• Docker streamlines container creation and management.
• It's also a collaborative platform for discovering and sharing containerized applications and services.

Note: Docker is not virtualization; it operates with a single underlying OS, partitioned into isolated environments.

Understanding Containers

• A container encapsulates all the components required to run an application, including the code, configurations, processes, networking, and dependencies.
• A container comprises:
  • The application code.
  • Configuration files.
  • Isolated processes.
  • Networking configurations to facilitate communication between containers.
  • Dependencies bundled within the container.
  • A minimal OS subset to support the application.

How Docker Works

Docker replicates essential Linux server services within the Linux Kernel for each container. Each container is a self-contained environment, isolated from others. For example, one container might run a Red Hat Linux-based database, while another runs an Ubuntu Linux-based web server that communicates with the database. Docker manages these setups efficiently.

About Docker

• Docker serves as both a client and a server program.
• It's a command-line tool (the "docker" command) for interacting with Docker.
• Docker also functions as a server program, managing running Linux systems.
• It provides the capability to build containers from code, including code dependencies.
• Docker facilitates container distribution across the internet, enabling users to discover and share containerized applications.
• Docker is also the name of the company behind these technologies.

Docker Common Commands

Here is a selection of frequently used Docker commands:

• docker build: Create an image from a Dockerfile.
• docker run: Launch a container based on an image.
• docker start: Begin an existing container.
• docker stop: Halt a running container.
• docker rm: Delete a stopped container.
• docker exec: Execute a command within a running container.
• docker pull: Download an image from a registry.
• docker push: Upload an image to a registry.
• docker images: List local machine images.
• docker ps: Display running containers.
• docker logs: View container logs.

Additional Docker commands:

• docker inspect: Retrieve detailed information about a container or image.
• docker login: Log in to a registry.
• docker logout: Log out from a registry.
• docker tag: Add a tag to a local repository image.
• docker save: Save an image to a tar archive.
• docker load: Load an image from a tar archive.
• docker system prune: Remove unused data locally.
• docker volume create: Create a volume.
• docker volume rm: Delete one or more volumes.

Please refer to the Docker documentation or use docker --help for a comprehensive list of commands.