有关Docker配置和相应操作系统选择的问题

Question

I am planning to build an environment for Web services using ECS at Docker.
However I am in trouble because I do not know what to do with the OS inside Docker.

I heard that it is common to build Docker individually for each service for general construction of Docker.
At first, there was a Docker that gathers Docker, and imagined in which Docker (server, DB, Redis ...) was created for each role.
If this is done, if you set Docker's OS for each role to general LinuxOS (such as CentOS), it seems that it will increase considerably only by OS memory capacity.
I just realized that there is a compact OS called CoreOS.

Then there are doubts.
Is it common for Docker's OS to be set to CoreOS for each role?
Is the assumption that I wrote so far is common?

It will be helpful if you can answer.

Answer 1

Not sure I understand the question, but you seem to misunderstand "layers" of a Docker image.

The base OS doesn't really matter all that much as long as you know how to install and manage services for that container OS.

For minimal base images, you can pick Alpine or CoreOS. For more substantial OS's that might match your production systems, then you can pick from Debian, CentOS, or Ubuntu.

For more reading see Elasticsearch switched to CentOS as a base .

You'll find that things are often easier to install when you can use apt or yum install

increase considerably only by OS memory capacity

Only once per machine (assuming running in a cluster/swarm), though. For example, if you share a base CentOS image between your web app and Redis Docker images, then only the extra layers to build the respective apps are created.

For a visual, let's assume I have a Python (or Ruby, Node, Golang, etc.) web app, a CLI utility written using that same language, and a database image built on one machine. You would build a general Python layer, then extend that onto the web and CLI images. All images build from the same base OS image

----------------
|  Web | CLI   |
---------------------
|    Python    | DB |
---------------------
|     Base image    |
---------------------