Introduction to docker for Beginner
Docker: Introduction
Docker is a open platform for containerization, It gives simplified apporach for building, shipping, and running applications. With the help of docker application along with its dependecies into container. This container can be deployed to any enviornment with Docker installed. Which makes the deployment process easier and ensures you application runs consistentaly across differnet enviornments.
It was first introduced in 2013 by Solomon Hykes as an open-source project, and it has since gained a popular in the software development community. It has become a one of the important tool in modern software development and is being used by many companies to streamline their development processes.
Understanding Docker
Before we start with Docker it is important to undersatand difference between Docker and Virtual Machine. Virtual machine runs a entair operating system including it’s kernel, on top of host operating system. Containers, on other hand share the host machine’s operating system kernel and run as isolated processes in user space on top of the host operating system. since containers are not virtual machines, and they do not require a hypervisor to run. Containers are particularly well-suited for deploying and running distributed applications that need to be deployed across multiple hosts or environments.
Docker has a client-server architecture, where the Docker client communicates with the Docker daemon, which runs on the host machine. The Docker daemon manages the containers, images, networks, and volumes.
The key components of Docker are:
- Dockerfile: A text file that contains the instructions for building a Docker image
- Docker image: A read-only template that contains the application and its dependencies
- Docker container: An instance of a Docker image that runs as a process on the host machine
- Docker registry: A repository for Docker images, such as Docker Hub
Installing Docker
To get started with Docker, you need to install it on your machine. Docker is available for Windows, Mac, and Linux. You can follow the offical installation page to complete installation https://docs.docker.com/engine/install/.
Once you’ve installed Docker, you can verify that it’s working by running the hello-world image. This image is a simple example that prints a message to the console.
Docker Images and Containers
Docker images are read-only templates that contain an application and its dependencies. Custom Docker images can be created by writing a Dockerfile, which contains the instructions for building the image. Docker containers are instances of Docker images that run as processes on the host machine. Containers can be started by specifying image from a registry (if it’s not already available locally) and starts a new container. You can also use Docker to pull and push images to a registry, such as Docker Hub. This makes it easy to share your images with others and to use images that others have created.
Dockerizing your Application
Dockerizing an application involves creating a Docker image that contains the application and its dependencies. This makes it easier to deploy the application to different environments and ensures that it runs consistently.
Application can be dockerized by creating the Docker images having application and its dependencies. First, the Dockerfile neeed to be created to build the image by providing instruciton. Once you’ve created the Dockerfile, you can build the image using the docker build command. This creates a new Docker image that you can run as a container.
Docker Compose
Docker Compose is a tool for defining and running multi-container Docker applications. It allows you to define the services that make up your application in a YAML file and then start them all with a single command. With Docker Compose, you can define the network connections between the containers, the volumes that should be shared between them, and any other configuration options.
Conclusion
Docker is a powerful tool that simplifies the process of building, shipping, and running.