Overview

I recently started learning docker and it was interesting. Docker uses client-server (docker-engine) architecture, it has its client components that talks to a server component using a restful API. A container is a special process running on your computer, all containers on a host share the operating system of the host.

Prerequisites

• Docker CLI and Desktop Installed.
• Node.js v22.14.0
• Git

Setup Instructions

• First, I wrote a simple application using node.js in app.js file

• I dockerized the application, meaning I made a small change so that it can be run by docker by adding a simple dockerfile.

A dockerfile is a plain text file that includes instructions that docker uses to package up this application into an image.

• To build the docker image, run the command

docker build -t hello-docker

• To run this image to on any computer running docker

docker run hello-docker

• Once we have the image; we can push it to DockerHub. DockerHub to docker is like GitHub to Git. It is a storage for docker images that anyone can use. The image must be tagged before pushing.

docker tag <image-id> <dockerhub-username>/<repository-name>:<tag>

• Then push

docker push amehmathias/hello-docker:latest

• Once our application image is on DockerHub, then we can put it on any machine running docker.

Challenge faced

I encountered an error while trying to push my application image to DockerHub without first tagging it

Based on the error message on the terminal, I noticed I have to tag my image before pushing it.