What is docker in a simple example?

Question

Docker

1.
Let's say I have a VPS and a bunch of any game is installed there

1. nginx
   
2. PHP SCRIPTS
   
3. MySQL
   
4. NODEJS SCRIPTS
   
5. APACHE
   
6. PYTHON SCRIPTS
   
7. MORE any game
   

Everything works
In the background, all sorts of SCREEN and other programs are spinning under 40.
As a control panel, something like ISPmanager or
How to make a backup of everything using docker and then deploy it to another server?
2.
If point 1 works, then what if all the game is spinning on Debian, and I wanted to deploy a backup on Centos, will it work or not?
If possible, with examples of how this is done.
Perhaps I just did not understand what docker is.

Answer 1

docker is not about server backup. If you want containerization of the operating system, then you need LXC / LXD.
And in your case, you need to refactor the entire contents of the server. In short, docker will help structure this dump of services and manage it more conveniently. But for this you need to make an effort.