How to correctly understand the essence of CoreOS and Docker?

Question

linux

Misters, explain please, whether correctly I interpret concepts? (Yes, for experienced people, a simple question, but I'm generally a designer)
CoreOS is an operating system on vps (for example). It has Docker installed. Each docker container has its own operating system, be it debian/ubuntu/centos with some application, for example nginx/mongo/etc.
That is, CoreOS is good for clustering and multiple containers, and docker isolates any application from each other, as an example, mongo can then be transferred from one node to another.
Did I understand everything correctly?

Answer 1

CoreOS operating system - Yes
It has Docker installed. - Yes,
a docker container is its own operating system - not really, it's more of an operating system emulator, but for a designer it can be considered so.
maybe then transfer mongo from one node to another - now they will tell you that transferring the container from node to node is bad manners and you need to build a new container on the new node and replicate the data. But in general, again, yes - it's possible.

Answer 2

xs what is your task
https://www.youtube.com/watch?v=-O9ArkgkorA here it is short and easy to listen to
https://yadi.sk/i/xoJ6VXxxgUMKd the container is also easy to read
- it's still not an OS, overhead the cost of its operation is minimal, in comparison with hypervisors,
its application features are not obvious (closed ports, you can’t (or already can) unix sockets between applications, connect partitions to access files), transferring is also not so easy - there is a sequence of inclusion of containers , state saving, etc.
but docker is the best solution for running many os-like containers/applications on one bare metal server compared to hypervisors

Answer 3

No, you misunderstood. You perceived docker as virtualization