How to Set Up CI/CD on AWS

📘 Chapter 3: Automating Deployments with CodeDeploy

🔍 Overview

AWS CodeDeploy is a fully managed deployment service that automates the process of releasing application updates to compute services like Amazon EC2, AWS Lambda, and Amazon ECS. It enables safe and repeatable deployments with minimal downtime, rollback options, and hooks for custom actions during different stages of deployment.

This chapter will cover:

• Types of deployments supported by CodeDeploy
• How to configure EC2 and Lambda deployments
• Writing the appspec.yml file
• Managing deployment groups
• Handling lifecycle hooks and rollbacks
• Integrating CodeDeploy into a CI/CD pipeline

🧠 1. What is AWS CodeDeploy?

AWS CodeDeploy automates code delivery to:

• EC2 instances (traditional in-place or blue/green)
• AWS Lambda functions
• ECS services (containerized)

It decouples deployment logic from your CI tool and ensures that updates are applied consistently.

🔑 Key Features

🚀 2. Deployment Types

✅ EC2 Deployment

Used when deploying traditional apps to virtual machines.

✅ Lambda Deployment

• Supports canary, linear, and all-at-once traffic shifting
• No infrastructure to manage
• Uses aliases and versions to handle routing

✅ ECS Deployment

• Deploys new Docker images to ECS services
• Integrated with CodePipeline and Fargate

🛠️ 3. Setting Up EC2 Deployment with CodeDeploy

✅ Step 1: Install CodeDeploy Agent

Install on each EC2 instance (Amazon Linux):

bash

sudo yum update -y

sudo yum install ruby wget -y

cd /home/ec2-user

wget https://bucket-name.s3.region.amazonaws.com/latest/install

chmod +x ./install

sudo ./install auto

sudo service codedeploy-agent start

✅ Use CodeDeploy EC2 IAM Role with AmazonEC2RoleforAWSCodeDeploy policy.

✅ Step 2: Create an Application in CodeDeploy

bash

aws deploy create-application \

  --application-name MyApp \

  --compute-platform Server

✅ Step 3: Create a Deployment Group

bash

aws deploy create-deployment-group \

  --application-name MyApp \

  --deployment-group-name MyAppDG \

  --deployment-config-name CodeDeployDefault.OneAtATime \

  --ec2-tag-filters Key=Name,Value=MyEC2Instance,Type=KEY_AND_VALUE \

  --service-role-arn arn:aws:iam::123456789012:role/CodeDeployServiceRole

📄 4. Writing the appspec.yml File

This file tells CodeDeploy how to install, stop, start, and validate the app.

✅ Basic Structure (EC2)

yaml

version: 0.0

os: linux

files:

  - source: /

    destination: /var/www/html

hooks:

  BeforeInstall:

    - location: scripts/stop_app.sh

      timeout: 180

      runas: root

  AfterInstall:

    - location: scripts/install_dependencies.sh

      timeout: 180

      runas: root

  ApplicationStart:

    - location: scripts/start_app.sh

      timeout: 180

      runas: root

📄 Sample Hook Script (start_app.sh)

bash

#!/bin/bash

cd /var/www/html

npm start &

📝 Ensure scripts are executable (chmod +x script.sh)

✅ For Lambda Deployments

yaml

version: 0.0

Resources:

  - myLambdaFunction:

      Type: AWS::Lambda::Function

      Properties:

        Name: MyFunction

        Alias: live

        CurrentVersion: 5

        TargetVersion: 6

🔄 5. Creating a Deployment (CLI or Console)

✅ CLI for EC2:

bash

aws deploy create-deployment \

  --application-name MyApp \

  --deployment-group-name MyAppDG \

  --s3-location bucket=my-bucket,bundleType=zip,key=MyAppBundle.zip

✅ CLI for Lambda:

bash

aws deploy create-deployment \

  --application-name MyLambdaApp \

  --deployment-group-name MyLambdaDG \

  --revision revisionType=AppSpecContent,appSpecContent={content=...}

🧪 6. Monitoring Deployments

✅ In Console:

• CodeDeploy → Deployments → View status per instance
• See logs per lifecycle hook

✅ CLI:

bash

aws deploy get-deployment \

  --deployment-id d-XXXXXXXX

🔁 7. Rollbacks and Failures

You can configure automatic rollbacks in the deployment group.

✅ Enable Auto Rollback

bash

aws deploy update-deployment-group \

  --application-name MyApp \

  --deployment-group-name MyAppDG \

  --auto-rollback-configuration enabled=true,events=DEPLOYMENT_FAILURE

🧩 Summary Table – EC2 Deployment Components