Docker - check private registry image version

Question

What CLI commands do I need to use in order to check if the image in my private docker registry is a newer version than the one currently running on my server?

E.g.

Answer 1

You can use a bash script running in a cron scheduled task:

#!/bin/bash

docker_instance='YOUR_RUNNING_INSTANCE'

instance_id=$(docker ps -qa --filter name=$docker_instance)
image_name_tag=$(docker inspect $instance_id | jq -r [] |.Config.Image')

if [ "-${image_name_tag}-" != "--" ]; then

    status=$(docker pull $image_name_tag | grep "Downloaded newer image")
    if [ "-${status}-" != "--" ]; then

        echo ">>> There is one update for this image ... "

        # stop the docker instance
        docker stop $docker_instance

        # remove the docker instance
        docker rm $docker_instance

        # restart the docker using the last command, using the new image from the remote repository
        run-my-docker-instance.sh

    fi
fi