Docker container architecture - A look under the hood

 Docker has revolutionised how we build, ship, and run applications.
If we every think how Docker does this magic behind the scenes, then we need to under the under the hood Docker architecture.

The Client-Server Model
At its core, Docker follows a client-server architecture.

This means there are two main components:

• Docker Client: This is the command-line interface (CLI) we interact with. We use commands like docker build, docker run, and docker push to tell Docker what to do.
• Docker Daemon: This is the workhorse. It listens to requests from the client and manages all the heavy lifting based on the docker client commands like building images, running containers, and handling storage.

Think of it like ordering food at a restaurant. You (the client) tell the waiter (the Docker client) what you want. The waiter relays that to the kitchen (the Docker daemon), where the magic happens.

Lets look at the Key Components: Beyond Client and Server
Besides the client and daemon, several other components play crucial roles:

• Docker Images: These are read-only templates that contain everything needed to run your application: code, runtime, libraries, and system tools. They're like blueprints for your containers.
• Docker Containers: These are runnable instances of images. They're isolated environments where your application runs. Think of them as individual houses built from the same blueprint.
• Docker Registry: This is a storage and distribution system for Docker images. Docker Hub is the public registry, but you can also have private registries. It's like a warehouse where blueprints are stored and shared.
• Dockerfile: This is a text file with instructions for building a Docker image. It's like a recipe that tells Docker how to assemble the blueprint

How These Components Work Together

1. User write a Dockerfile to define your application's environment
2. The Docker client sends a docker build command with the Dockerfile to the daemon
3. The daemon builds the image according to the instructions and stores it locally
4. User use docker run to create a container from the image
5. The daemon downloads any necessary layers from the registry, isolates the container's environment, and starts your application
6. User use docker push to share your image on a registry

Benefits of this Architecture

• Isolation: Applications run in isolated containers, preventing conflicts and dependencies.
• Portability: Images can run on any system with Docker installed, ensuring consistency across environments.
• Efficiency: Images are built in layers, minimizing storage space and download times.
• Scalability: Containers can be easily scaled up or down to meet demand.