ECS, ECR, Docker

Question 1

vm vs docker

Answer 1

• vm - virtualized hardware, uses hypervisor
• docker - lightweight containers run using docker daemon

Question 2

ECS - elastic container service

Answer 2

• task = pod - launches containers (up to 10 per task definition)
  
  • task definition - metadata in json form to tell ecs how to run container
    
    • image name, ports, memory, env variables, IAM role, etc.
      
      • Secrets - use SSM parameter store or Secrets manager
  • shared storage (bind mounts) - per task, works with ec2 and fargate
    
    • use for ephemeral data between multiple containers, and sidecar containers for metrics, etc.

Question 3

IAM task roles

Answer 3

• specific roles for each tasks
• task role defined in task definition

Question 4

data volumes (EFS)

Answer 4

• works with both ec2 and fargate launch types
• S3 CANNOT be mounted for ECS tasks

Question 5

Terminate an instance in stopped state leads to

Answer 5

Synchronization issues. Container instance isn’t automatically removed from the cluster