AWS ECS & Fargate

Run containerized applications on Amazon ECS with Fargate serverless compute or EC2 launch type.

When to Use This Skill

• Deploying Docker containers to AWS without managing servers (Fargate)
• Running microservices with service discovery and load balancing
• Setting up blue/green or rolling deployments for containerized apps
• Configuring auto-scaling for container workloads
• Migrating from docker-compose or Kubernetes to ECS
• Troubleshooting task failures, health check issues, or networking problems

Prerequisites

• AWS CLI v2 installed and configured
• Docker installed for building and pushing images
• IAM permissions: ecs:*, ecr:*, elasticloadbalancing:*, logs:*, iam:PassRole
• An ECR repository for storing container images
• A VPC with subnets and an ALB (see aws-vpc (aws-vpc))

Cluster Setup

# Create an ECS cluster with Container Insights enabled
aws ecs create-cluster \
  --cluster-name production \
  --capacity-providers FARGATE FARGATE_SPOT \
  --default-capacity-provider-strategy '[
    {"capacityProvider": "FARGATE", "weight": 1, "base": 2},
    {"capacityProvider": "FARGATE_SPOT", "weight": 3}
  ]' \
  --settings '[{"name": "containerInsights", "value": "enabled"}]'

# List clusters
aws ecs list-clusters

# Describe cluster details
aws ecs describe-clusters --clusters production --include STATISTICS ATTACHMENTS

Push Image to ECR

# Create ECR repository
aws ecr create-repository \
  --repository-name myapp \
  --image-scanning-configuration scanOnPush=true \
  --encryption-configuration encryptionType=KMS

# Authenticate Docker to ECR
aws ecr get-login-password --region us-east-1 | \
  docker login --username AWS --password-stdin 123456789012.dkr.ecr.us-east-1.amazonaws.com

# Build, tag, and push
docker build -t myapp:latest .
docker tag myapp:latest 123456789012.dkr.ecr.us-east-1.amazonaws.com/myapp:latest
docker push 123456789012.dkr.ecr.us-east-1.amazonaws.com/myapp:latest

Task Definition

{
  "family": "myapp",
  "networkMode": "awsvpc",
  "requiresCompatibilities": ["FARGATE"],
  "cpu": "512",
  "memory": "1024",
  "executionRoleArn": "arn:aws:iam::123456789012:role/ecsTaskExecutionRole",
  "taskRoleArn": "arn:aws:iam::123456789012:role/ecsTaskRole",
  "containerDefinitions": [
    {
      "name": "myapp",
      "image": "123456789012.dkr.ecr.us-east-1.amazonaws.com/myapp:latest",
      "essential": true,
      "portMappings": [
        {
          "containerPort": 8080,
          "protocol": "tcp"
        }
      ],
      "environment": [
        {"name": "NODE_ENV", "value": "production"},
        {"name": "PORT", "value": "8080"}
      ],
      "secrets": [
        {
          "name": "DB_PASSWORD",
          "valueFrom": "arn:aws:secretsmanager:us-east-1:123456789012:secret:myapp/db-password"
        },
        {
          "name": "API_KEY",
          "valueFrom": "arn:aws:ssm:us-east-1:123456789012:parameter/myapp/api-key"
        }
      ],
      "healthCheck": {
        "command": ["CMD-SHELL", "curl -f http://localhost:8080/health || exit 1"],
        "interval": 30,
        "timeout": 5,
        "retries": 3,
        "startPeriod": 60
      },
      "logConfiguration": {
        "logDriver": "awslogs",
        "options": {
          "awslogs-group": "/ecs/myapp",
          "awslogs-region": "us-east-1",
          "awslogs-stream-prefix": "ecs",
          "awslogs-create-group": "true"
        }
      },
      "ulimits": [
        {"name": "nofile", "softLimit": 65536, "hardLimit": 65536}
      ]
    }
  ]
}

# Register the task definition
aws ecs register-task-definition --cli-input-json file://task-definition.json

# List task definition revisions
aws ecs list-task-definitions --family-prefix myapp

# Deregister an old revision
aws ecs deregister-task-definition --task-definition myapp:1

Create Service with ALB

# Create the CloudWatch log group first
aws logs create-log-group --log-group-name /ecs/myapp
aws logs put-retention-policy --log-group-name /ecs/myapp --retention-in-days 30

# Create ECS service with load balancer
aws ecs create-service \
  --cluster production \
  --service-name myapp \
  --task-definition myapp:2 \
  --desired-count 3 \
  --launch-type FARGATE \
  --platform-version LATEST \
  --deployment-configuration '{
    "deploymentCircuitBreaker": {"enable": true, "rollback": true},
    "maximumPercent": 200,
    "minimumHealthyPercent": 100
  }' \

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