Elastic Container Service (ECS)

Container-related services

Essentials

• Container management service that supports Docker

• It allows you to easily create and manage a fleet of Docker containers on a cluster of EC2 instances.

  • Higher Instance Utilization

  • Consistency between all environments

  • Microservices

  • Continuous Deployment - automate builds

  • Load Balancing (ELB)

  • Autoscaling

Components

• Docker Image

• Container Registry (ECR)

• Task Definitions

  • Docker Images

  • CPU, Memory

  • Launch Type - EC2 or Fargate (managed, serverless)

• ECS Cluster

  • EC2 Container Instances

    • ECS Agents

      • Run Tasks from ECR

ECS Agent

• Runs on each EC2 instance in the ECS cluster

• It communicates information about the instances to ECS, including:

  • Running tasks

  • Resource utilization

• The ECS agent is also responsible for starting/stopping tasks (when told to by ECS)

ECS Tasks

• Actual representation of a Task Definition on an EC2 instance inside of your container cluster.

• ECS agent will start/stop these tasks based on instruction/schedule

Task Definition

• A JSON formatted text file that contains the "blueprint" for your application, including:

  • Which container/docker image to use

  • The repository (container registry) the image is located in

  • Which ports should be open on the container instance

  • What data volumes should be used with the container

Container/Docker Image

• Built from a Dockerfile

  • A plain text file (script) that specifies all of the components that are included in the container.

  • Instructions for what will be placed inside a given container.

• Contains all the downloaded software, code, runtime, system tools, and libraries (as outlined in the Dockerfile)

  • i.e. If the Dockerfile specifies PHP to be downloaded and installed, then the container/Docker Image will have PHP downloaded and installed.

Elastic Container Service for Kubernetes (EKS)

• Manages availability and scalability of Kubernetes control plane nodes

  • Starts and stops containers

  • Schedule containers

  • Replaces unhealthy nodes