The Potential of Docker in AWS: A Guide

by Tola Ore-Aruwaji

Introduction

Development environments today requires a robust platform that can handle complex tasks while optimizing resource utilization. Docker, in combination with Amazon Web Services (AWS), offers an incredibly potent solution for developers and DevOps engineers looking to simplify deployment and scale their applications. In this guide, we will delve into the magic of Docker and AWS, helping you enable more enhanced deployments in your application.

What is Docker

Docker is an open-source platform that simplifies the process of developing, shipping, and running applications. With Docker, your application runs within containers, ensuring it works uniformly irrespective of the environment. Docker not only ensures seamless application deployment but also saves time by creating a consistent testing environment.

The Role of AWS

AWS is Amazon's renowned cloud platform offering over 200 fully-featured services from data centers globally. AWS is broadly adopted due to its scalability, security, and comprehensive suite of cloud services. With AWS, you can manage applications, store data, and perform a host of other cloud-related tasks.

Running Docker on AWS

One of the key advantages of AWS is its native support for Docker. AWS Elastic Beanstalk, Amazon Elastic Container Service (ECS), and Amazon Elastic Kubernetes Service (EKS) are powerful AWS services that allow you to deploy Docker containers.

AWS Elastic Beanstalk

This high-level service automatically handles all the details such as capacity provisioning, load balancing, scaling, and application health monitoring. It's excellent for developers who want to deploy and manage applications without worrying about the underlying infrastructure. You can easily deploy your Docker applications by uploading your Dockerfile and related files, and Elastic Beanstalk handles the rest.

Elastic Beanstalk uses a Dockerrun.aws.json file in the source bundle to understand how to deploy the Docker container(s). Here's an example for a simple application:

{
  "AWSEBDockerrunVersion": "1",
  "Image": {
    "Name": "123456789012.dkr.ecr.region.amazonaws.com/my-app:latest",
    "Update": "true"
  },
  "Ports": [
    {
      "ContainerPort": "8080"
    }
  ]
}

Create an Elastic Beanstalk Application

  • Navigate to the Elastic Beanstalk console in your AWS account.
  • Click on the Create a new environment button.
  • Select the Web server environment and click Select.
  • Fill in the necessary details for your environment like the application name, environment name, and domain.
  • In the platform settings, select Docker from the dropdown list.
  • In the application code section, select Upload your code, then upload a ZIP file containing your Dockerrun.aws.json.
  • Click Create environment.

AWS will now handle the rest and start your environment. You can view the status of your environment on the Elastic Beanstalk console. Once the environment status is Green, you can navigate to the provided URL to see your running application.

Amazon ECS

ECS is a scalable, high-performance container orchestration service that supports Docker containers and allows you to run and scale containerized applications on AWS. With ECS, there is no need for you to install, update, or operate your own container orchestration software, manage and scale a cluster of virtual machines, or schedule containers on those virtual machines.

Once you have a Docker image, you need to push it to Elastic Container Registry (ECR), a fully-managed Docker container registry that makes it easy for developers to store, manage, and deploy Docker container images.

First, create a repository in ECR:

aws ecr create-repository --repository-name my-app

Authenticate Docker to the ECR registry:

aws ecr get-login-password --region region | docker login --username AWS --password-stdin 123456789012.dkr.ecr.region.amazonaws.com

Tag the Docker image:

docker tag my-app:latest 123456789012.dkr.ecr.region.amazonaws.com/my-app:latest

Finally, push the Docker image:

docker push 123456789012.dkr.ecr.region.amazonaws.com/my-app:latest

Create an ECS Cluster

You can use the AWS Management Console, the AWS CLI, or the ECS API to create an ECS cluster.

Here's how to create a new ECS cluster using the AWS CLI:

aws ecs create-cluster --cluster-name my-cluster

Define a Task Definition

A task definition is a text file in JSON format that describes one or more containers. Here's an example of a task definition for your application:

{
    "family": "my-app-task-def",
    "containerDefinitions": [
        {
            "name": "my-app",
            "image": "123456789012.dkr.ecr.region.amazonaws.com/my-app:latest",
            "cpu": 100,
            "memory": 200,
            "essential": true,
            "portMappings": [
                {
                    "containerPort": 8080,
                    "hostPort": 80
                }
            ]
        }
    ]
}

You can register this task definition with the register-task-definition command:

aws ecs register-task-definition --cli-input-json file://my-app-task-def.json

Run a Task

Finally, you can run a task using the run-task command:

aws ecs run-task --cluster my-cluster --task-definition my-app-task-def

Amazon EKS

EKS is a managed service that makes it easier for you to run Kubernetes on AWS without needing to install and operate your own Kubernetes clusters. Kubernetes is a powerful open-source system for automating deployment, scaling, and management of containerized applications. If you are already using Kubernetes, EKS is a great way to use Kubernetes with Docker on AWS.

Just as with ECS, you need to create a Docker image. You can use the Dockerfile from the previous ECS example to create a Docker image for a simple Node.js application:

docker build -t my-app .

Next, push the Docker image to AWS Elastic Container Registry (ECR). You can follow the exact same steps as described in the ECS example:

# Create repository
aws ecr create-repository --repository-name my-app

# Authenticate Docker to ECR
aws ecr get-login-password --region region | docker login --username AWS --password-stdin 123456789012.dkr.ecr.region.amazonaws.com

# Tag Docker image
docker tag my-app:latest 123456789012.dkr.ecr.region.amazonaws.com/my-app:latest

# Push Docker image
docker push 123456789012.dkr.ecr.region.amazonaws.com/my-app:latest

Create an EKS Cluster

You can use eksctl, a simple command line utility for creating and managing Kubernetes clusters on Amazon EKS. Install eksctl following instructions at https://eksctl.io/introduction/#installation.

Create a cluster using the following command:

eksctl create cluster --name my-cluster --version 1.21 --region region --nodegroup-name my-nodes --nodes 2 --nodes-min 1 --nodes-max 3 --managed

Define a Kubernetes Deployment

A Kubernetes deployment is a blueprint for your application. Create a file named my-app-deployment.yaml with the following content:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app-deployment
  labels:
    app: my-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app
        image: 123456789012.dkr.ecr.region.amazonaws.com/my-app:latest
        ports:
        - containerPort: 8080

Then apply the deployment: 

kubectl apply -f my-app-deployment.yaml

Create a Kubernetes Service

A Kubernetes service is an abstraction layer that defines a logical set of pods (the running containers in your deployment) and enables external traffic exposure, load balancing and service discovery for those pods. Create a file named my-app-service.yaml with the following content:

apiVersion: v1
kind: Service
metadata:
  name: my-app-service
spec:
  selector:
    app: my-app
  ports:
    - protocol: TCP
      port: 80
      targetPort: 8080
  type: LoadBalancer

Then apply the service:

kubectl apply -f my-app-service.yaml

Advantages of Using Docker with AWS

Using Docker and AWS together presents several advantages:

  • Portability: Docker enables you to package your application with its dependencies into a standardized unit. This level of portability makes it easy to run your applications across any machine without worrying about the specific setup or environment.
  • Resource Optimization: Docker containers are lightweight, enabling you to run multiple containers simultaneously on a given host. AWS provides a wide range of instance types to choose from, depending on the nature of your application.
  • Scalability: With AWS, you can scale your applications easily by increasing the number of container instances as demand grows. Services like Elastic Beanstalk and ECS allow automatic scaling.
  • Continuous Integration/Continuous Deployment (CI/CD): AWS and Docker can enhance your CI/CD pipeline. AWS CodePipeline and CodeBuild provide you with the tools to automate your software release processes quickly, reliably, and efficiently.

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