Read this article to get a brief intro on why docker.
Let’s consider a scenario where I have built an application on Ubuntu and I want my friend Keyser Soze to give me a feedback on it.
Keyser Soze uses a mac.
Now in order to run my application, he will have to install all mac version of the dependencies of my app.
To summarise anyone with a different operating system will have to repeat this process unnecessarily.
I want some way which ensures that once I build my application, anyone can run it irrespective of what OS are they using or what version of the dependency they have or even they have it or not.
To achieve this exact thing containers came into being.
A container isolates the application it runs completely from any kind of dependencies including OS or any other external environment.
A container can be thought of as a wrapper over our application.
It packs all of the application’s dependencies including the OS it runs on.
As in the image below container separates nginx application from the outside environment, be it OS or any other thing.
