Are there different images for different OS on docker hub

Question

When i run the following command

docker run mongo

It will download the mongo image and run it on container.

I am running Linux on VM.

My OS details are as follows:

NAME="CentOS Linux" VERSION="7 (Core)"

In case I am using different OS /Mac Machine / Windows, how does docker determine which image to pull. As I understand there is a single image on docker hub for mongo or is it that we can specify a specific image to run based on our OS.

At least we need take care of downloading specific version of mongo when doing installation on our local machine (when not using containers).

How is this taken care of by dockers.

Thanks.

Answer 1

The OS that you are running is for the most part irrelevant when it comes to pulling a docker image. As long as you are running docker (and the versions of docker are a little different from windows to Mac to Linux) on your host, you can pull any image you want. You can pull the same mongo image are run it in any operating system.

The image hides the host operating system making it easy to build an image an deploy pretty much in any machine.

Having said that you may be getting confused because image makers many times use different OS to build their applications. A quick example is people building application using an Ubuntu image but switching to an alpine based image for deployment because that is so much smaller. However, both images will run pretty much anywhere.

Answer 2

Probably you are confused with terms OS and Architecture ?

The OS does not really matter, because, as @camba1 mentioned, the Docker daemon handles all that stuff.

What matters, is architecture, because Linux can run on ARM , AMD64 , etc. So, the Docker daemon must know which image is good for current architecture.

Here is a good article regarding this question.