Elastic Container Service¶

ECS is AWS Docker Service. You can launch and modify containers as tasks in multiple ways depending on your application and scale.

Features¶

• support NLB, ALB
• support block storage – EFS
  • use case → persistent multi-AZ shared storage for your containers.
  • S3 can't be mounted in EC task.

Launch Types¶

EC2 Based¶

• Need to have a running EC2 as the host for your containers
• you must provision & maintain the infrastructure.
• You are billed for depending on the EC2
• The EC2 Instance must be running the ECS agent

Fargate Based / ECS Cluster¶

• No need to provision-Serverless
• Need tasks definitions
• Billed for CPU and memory used
• by default 20gb of free block storage

Roles¶

Instance Profile¶

• used by the ECS Agent
• Only used for host EC2
• Used to create and run image on EC2

Task Role¶

• Defines Permissions for the code running in the container (access to other services)
• each task can have a specific role

ECS Fargate Autoscaling¶

• Scale on CPU, Mem or ALB traffic per target
  • ALB Request count per target - metric coming from ALB
• Scaling Fargate is easier
• Combine ECS cluster capacity prover paired with Auto Scaling group

Modes¶

• Target tracking
  • Scale based on target value for specific CloudWatch metric
• Step calling
  • Scale based on specific CloudWatch Alarm
• Scheduled scaling
  • Scale based on specific date/time (predictable changes)

EC2 Autoscaling¶

• Horizontal scaling.
  • Add more EC2 instances.
• Auto Scaling Group scaling.
  • Scale your ASG based on CPU utilization.
  • Add EC2 instances over time.
• EC2 Cluster capacity provider.
  • Used to auto provision and scale the infra for your ECS tasks.
  • Capacity provider paired with an auto-scaling group
  • add EC2 instances when you are missing capacity (CPU, RAM)

Advanced Use Cases¶

• Use EventBride or docs/messaging/SQS to launch container, process tasks and shut down container afterward e.g: