Should I Set docker image version in docker-compose?-CodePudding

Imagine I have docker-compose.yml for adding mongo as a container, is it a good thing to set verion in front of image name or let it to be the latest by default?

version: '3.8'
services:
  mongo:
    image: mongo:4.0
    ports:
      - "27017:27017"

Actually what is the pros and cons for application in development and production realeses?

image: mongo:4.0 VS image: mongo

CodePudding user response：

Including a version number as you've done is good practice. I'd generally use a major-only image tag (mongo:4) or a major minor tag (mongo:4.4) but not a super-specific version (mongo:4.4.10) unless you have automation to update it routinely.

Generally the Docker Hub images get rebuilt fairly routinely; but, within a given patch line, only the most-recent versions get patches. Say the debian:focal base image gets a security update. As of this writing, the mongo image has 4, 4.4, and 4.4.10 tags, so all of those get rebuilt, but e.g. 4.4.9 won't. So using a too-specific version could mean you don't get important updates.

Conversely, using latest means you just don't care what version you have. Your question mentions mongo:4.0 but mongo:latest is currently version 5.0.5; are there compatibility issues with that major-version upgrade?

The key rules here are:

If you already have some image:tag locally, launching a container will not pull it again, even if it's updated in the repository.
Minor-version tags like mongo:4.4 will continue to get updates as long as they are supported, but you may need to docker-compose pull to get updates.
Patch-version tags like mongo:4.4.9 will stop getting updates as soon as there's a newer patch version, even if you docker pull mongo:4.4.9.
Using a floating tag like ...:latest or a minor-version tag could mean different systems get different builds of the image, depending on what they have locally. (Your coworker could have a different mongo:latest than you; this is a bigger problem in cluster environments like Kubernetes.)

CodePudding user response：

I think it's a good thing to put version in front of the image name, you can manage them more easily, but you have to be careful to pass the update regularly to avoid loopholes.