Elastic Container Service (ECS)

Launch Docker containers on AWS = Launch ECS Tasks on ECS Clusters

On ECS host, you create a ECS cluster where you deploy the task , consisting of containers built by the images your own or in ECR (AWS managed registry)

Container definition = (which image to use & which ports to expose)

Task definition = contained One or more container make up as a single application, store the resources used by the task (eg CPU/ memory), task role for security & resources

Task role: IAM role a task can assume, allow permission to use AWS resources

Service definition: how we want the task to scale (aka how many copies), load distribution, restarts…

Untitled.png

ECS launch type

1. EC2 mode
   • Use EC2 as host within your VPC, need to manage them
   • ECS agent is put into EC2 to allow the control of containers
   • need to worry about capacity and availability
   • host cost is needed
2. Fargate mode
   • don’t have to manage EC2, no service to manage (serverless)
   • just create task definitions
   • Host on a Fargate shared Infrastructure outside the VPC, where the task injected into VPC
   • Still be able to access inside or outside VPC with the IP
   • only pay for the container resources consumed

IAM roles for ECS

• EC2 Instance Profile (EC2 Launch Type only:
• Used by the ECS agent
• Makes API calls to ECS service
• Pull Docker image from ECR
• Reference sensitive data in Secrets Manager or SSM Parameter Store ECS Task Role:
• Allows each task to have a specific role
• Use different roles for the different ECS Services you run
• Task Role is defined in the task definition

Load Balancer Integrations

• if a user need to access ECS
• Application Load Balancer - supported and works for most use cases
• Network Load Balancer - recommended only for high throughput / high performance use cases, or to pair it with AWS Private Link

Data Volumes (EFS)

• Mount EFS file systems onto ECS tasks
• Works for both EC2 and Fargate launch types
• Tasks running in any AZ will share the same data in the EFS file system
• Use cases: persistent multi-AZ shared storage for your containers
• Amazon S3 cannot be mounted as a file system