Containers

Containers Quick Notes

Core Vocabulary

• Image: Layered package of app + dependencies.
• Registry: Where images live (ECR on AWS).
• Task / pod: Running unit of one or more containers.

Amazon ECS

• Definition chain: container definition → task definition (CPU/mem, task role) → service.
• Launch types:
• • EC2: You pay for instances + EBS.
  • Fargate: You pay for vCPU + memory the task requests (no servers).
• Scale services with Application Auto Scaling (CPU, memory, ALB request count).

Amazon EKS

• Managed Kubernetes control plane (multi-AZ); workers in your VPC.
• Vocabulary: cluster / node / pod / service.
• Scale nodes with Kubernetes Cluster Autoscaler + EC2 Auto Scaling groups.
• Fargate also works with EKS for serverless pods.

When to Pick What

Need: Choose

AWS-native containers, simple: ECS

Kubernetes APIs / portability: EKS

No EC2 to manage: Fargate (ECS or EKS)

Private image store: ECR

Related

• Long app bootstrap (>45 min): Golden AMI + thin user data (Beanstalk / ECS hosts alike).
• Microservices that already speak ActiveMQ/JMS → Amazon MQ (not a forced SNS/SQS rewrite).