Ok, so here's we're going to learn how to reuse images. We often follow the principle of build once deploy anywhere and for that we need to maintain our images in a repository for later reuse.
For this tutorial, we'll use amazon ECR. I've logged into Amazon AWS console and searched for ECR.
Create a repository
The best way to create a repository is probably to follow this https://docs.aws.amazon.com/AmazonECR/latest/userguide/what-is-ecr.html. It even describes how to create an IAM user and use that to manage the ECR interactions, instead of using the root account.
The repository I've created is called blogrepo
Creating and Pushing an image.
For this, we're going to create a bare minimum express application and a Dockerfile
user@host:~/ecr-push-demo-app$ touch Dockerfile
user@host:~/ecr-push-demo-app$ touch app.js
user@host:~/ecr-push-demo-app$ touch package.json
user@host:~/ecr-push-demo-app$ npm install express --save
Put the following in these files
In app.js
//app.js
var express = require("express");
var app = express();
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.get("/", function (req, res, next) {
res.send({ title: "Express", application: "Application 1" });
});
app.listen(3000, () => console.log("Running on http://localhost:3000"));
In package.json
{
"name": "ecr-push-demo-app",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"start": "node app.js"
},
"keywords": [],
"author": "",
"license": "ISC",
"dependencies": {
"express": "^4.17.1"
}
}
and finally, in the Dockerfile
FROM node:12-slim
WORKDIR /app
COPY ./package*.json ./
RUN npm install
COPY ./ ./
EXPOSE 3000
# Run the code
CMD [ "npm", "start" ]
Build the image
Lets build the image and tag it as blogrepo20201120
$ sudo docker build -t blogrepo20201120 .
Lets tag this image for pushing to ecr and then push the image
Just a reminder, the repository I've created on ECR console is called
blogrepoand I created this inap-south-1region
$ docker tag blogrepo20201120:latest your_aws_account_id.dkr.ecr.ap-south-1.amazonaws.com/blogrepo:latest
$ docker push your_aws_account_id.dkr.ecr.ap-south-1.amazonaws.com/blogrepo:latest
Lets see if we can pull the image and run it
$ docker pull your_aws_account_id.dkr.ecr.ap-south-1.amazonaws.com/blogrepo:latest
$ sudo docker run -p 3000:3000 -d your_aws_account_id.dkr.ecr.ap-south-1.amazonaws.com/blogrepo:latest
That's all. Just open your browser to http://localhost:3000
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