Docker Primer
=============

Docker is an open-source platform that simplifies the process of
building, deploying, and running applications in containers. Containers
are lightweight, portable, and self-contained environments that package
an application, along with its dependencies, libraries, and runtime, to
ensure consistent behavior across different platforms and environments.

Main concepts and components of Docker:
---------------------------------------

**Docker Engine**: The core component of Docker, responsible for
creating and managing containers. It runs on the host operating system
and communicates with the Docker client using a REST API.

**Dockerfile**: A script containing instructions to build a Docker
image. It defines the base image, application source code, dependencies,
and configurations required to create a containerized application.

**Docker Image**: A read-only template used to create Docker containers.
Images are created from Dockerfiles and stored in a registry, such as
Docker Hub or a private registry.

**Docker Container**: A lightweight, portable, and self-contained
environment created from a Docker image. Containers run the application
and its dependencies, isolated from the host system and other
containers.

**Docker Hub**: A public registry for sharing and distributing Docker
images. It provides a centralized platform for developers to store,
manage, and share container images.

**Docker Compose**: A tool for defining and running multi-container
Docker applications. It uses a YAML file (docker-compose.yml) to
configure the application's services, networks, and volumes.

Basic Commands
--------------

Here are some basic Docker commands that are essential when working with
Docker:

1. **Build an image**: Build a Docker image from a Dockerfile in the
   current directory.

::

   docker build -t image-name:tag .

2. **List images**: Display a list of Docker images available on your
   local system.

::

   docker images

3. **Run a container**: Create and start a new Docker container from an
   image.

::

   docker run -d -p host-port:container-port --name container-name image-name:tag
   -d: Run the container in detached mode (in the background).
   -p: Map the host port to the container port.
   --name: Assign a name to the container for easier reference.

4. **List containers**: Show a list of all running containers.

``docker ps``

To list all containers, including stopped ones, use:

``docker ps -a``

5. **Stop a container**: Stop a running container.

``docker stop container-name-or-id``

6. **Start a container**: Start a stopped container.

``docker start container-name-or-id``

7. **Remove a container**: Delete a stopped container.

``docker rm container-name-or-id``

8. **Remove an image**: Delete a Docker image from your local system.

``docker rmi image-name:tag``

9. **Container logs**: Display logs from a running container.

``docker logs container-name-or-id``

10. **Execute a command inside a container**: Run a command within a
    running container.

``docker exec -it container-name-or-id command``

For example, to open a shell inside a running container, use:

``docker exec -it container-name-or-id /bin/bash``

11. **Pull an image**: Download a Docker image from a registry (e.g.,
    Docker Hub).

``docker pull image-name:tag``

12. **Push an image**: Upload a Docker image to a registry (e.g., Docker
    Hub). Make sure you are logged in with docker login and the image is
    tagged with your username.

``docker push username/image-name:tag``

To get started with Docker, follow these steps:

1. **Install Docker**: Download and install Docker for your operating
   system from the official website
   (https://www.docker.com/get-started).
2. **Use the provided dockerfile** in the repository