It is a common problem in software development where an application that runs perfectly fine on one machine might not work on another machine due to differences in the underlying infrastructure, such as operating systems, libraries, dependencies, or hardware.
For instance, if a developer creates an application on their local machine with specific dependencies and libraries installed, it may work flawlessly on their machine. However, when they pass it on to someone else with a different configuration or environment, the application might not work as expected due to the differences in the environments.
Docker is a containerization technology that allows you to package your application and its dependencies into a single, lightweight, and portable unit called a container and it allows you to build test and deploy applications and this ensures that your application runs on any environment. ** Let's understand this with the help of an example:**
Imagine you are a chef preparing a dish in your kitchen. You need various ingredients, such as vegetables, spices, and sauces, to make the dish. You have your own set of cooking tools and utensils that you are comfortable with, and you know exactly how to use them to make the perfect dish.
Now, let's say you are asked to cook the same dish in someone else's kitchen, which has a different set of cooking tools and utensils, and the ingredients are arranged differently. You might face some challenges in using the unfamiliar tools, finding the ingredients you need, and adjusting your recipe to suit the new environment.
In this scenario, Docker is like a portable kitchen that you can take with you anywhere you go. You can package your recipe and all the necessary ingredients, cooking tools, and utensils into a container that you can carry with you. This way, you can cook the same dish anywhere you go, regardless of the underlying infrastructure, and you don't have to worry about using unfamiliar tools or finding the right ingredients.
Just as a portable kitchen provides a consistent environment for cooking, Docker provides a consistent runtime environment for running applications, making it easier to deploy and scale applications across different environments.