section 18 docker,eks

• Docker


  A software development platform to deploy apps using container technology
• Docker containers


  • Apps are packaged into containers
  • Containers are standardized and can run on any operating system
  • Containers have predictable behavior and are easy to maintain and deploy
  • Can run with any language, operating system, or technology
• Use cases for Docker

  • Microservice architecture
  • Lift and shift apps from on-premises to the cloud
  • Anytime you want to run a container
• How Docker works on an operating system

  1. Run a Docker agent on a server (e.g. EC2 instance)

  2. Start Docker containers, which can contain different applications (e.g. Java, Node.js)

  3. Can also run databases in Docker containers
• Docker Repository


  Where Docker images are stored, options include Docker Hub (public) and Amazon ECR (private)
• Docker vs Virtual Machines

  • Docker is a virtualization technology but resources are shared with the host, allowing more containers to run on a single server
  • Virtual machines have a hypervisor and separate guest operating systems, providing more isolation but less resource efficiency
• Getting started with Docker


  1. Write a Dockerfile to define the container

  2. Build the Docker image from the Dockerfile

  3. Store the Docker image in a repository (Docker Hub or Amazon ECR)

  4. Pull the Docker image from the repository and run it as a container
• Docker container management on AWS

  • Amazon ECS (Elastic Container Service)
  • Amazon EKS (Elastic Kubernetes Service)
  • AWS Fargate (serverless container platform)
  • Amazon ECR (Elastic Container Registry to store container images)
• Docker containers


  Lightweight, portable, and isolated runtime environments for running applications
• Docker images


  Templates used to create Docker containers
• Docker images and containers

  Together, they enable developers to package, deploy, and manage applications consistently across different environments
• Docker images


  • Read-only templates used to create Docker containers
  • Contain application code, runtime, dependencies, libraries, and other configuration files needed to run an application
  • Built using Dockerfile, a text file with instructions for building the image layer by layer
  • Stored in repositories like Docker Hub or Amazon ECR, can be shared, versioned, and reused
  • Immutable, any changes result in a new image with a new tag/version
• Docker containers

  • Lightweight, standalone, and executable software packages that contain everything needed to run an application
  • Provide a consistent environment for applications to run across different computing environments
  • Isolate applications from the underlying infrastructure, ensuring consistent execution
  • Portable and can be easily deployed on any system that supports Docker
• Building Docker images


  1. Use Dockerfiles to define the instructions

  2. Docker images can be deployed and run on various platforms, including AWS
• Docker container


  • Still have the infrastructure and the host OS, which may be an EC2 instance
  • Have the Docker Daemon, and on top of it, many lightweight containers that can cohabitate together, sharing networking and data
• Docker containers vs virtual machines

  Less secure than virtual machines, but allow running more containers on a single server
• Docker commands


  1. docker run: Start a container from a Docker image

  2. docker build: Build a Docker image from a Dockerfile

  3. docker push: Push a Docker image to a registry

  4. docker pull: Pull a Docker image from a registry
• docker-compose


  Manage multi-container Docker applications
• Docker containers


  Lightweight, portable, and isolated runtime environments for running applications
• Docker images


  Templates used to create Docker containers
• Docker images and containers

  Together, they enable developers to package, deploy, and manage applications consistently across different environments
• Docker images


  • Read-only templates used to create Docker containers
  • Contain application code, runtime, dependencies, libraries, and other configuration files needed to run an application
  • Built using Dockerfile, a text file with instructions for building the image layer by layer
  • Stored in repositories like Docker Hub or Amazon ECR, can be shared, versioned, and reused
  • Immutable, any changes result in a new image with a new tag/version
• Docker containers


  • Lightweight, standalone, and executable software packages that contain everything needed to run an application
  • Provide a consistent environment for applications to run across different computing environments
  • Isolate applications from the underlying infrastructure, ensuring consistent execution
  • Portable and can be easily deployed on any system that supports Docker
• Building Docker images


  1. Use Dockerfiles to define the instructions

  2. Docker images can be deployed and run on various platforms, including AWS
• Docker container


  • Still have the infrastructure and the host OS, which may be an EC2 instance
  • Have the Docker Daemon
  • Can have many lightweight containers running on top of the Docker Daemon, sharing networking and data
• Docker containers vs virtual machines

  Less secure than virtual machines, but allow running more containers on a single server
• Docker commands


  1. docker run: Start a container from a Docker image

  2. docker build: Build a Docker image from a Dockerfile

  3. docker push: Push a Docker image to a registry

  4. docker pull: Pull a Docker image from a registry

  5. docker-compose: Manage multi-container Docker applications
• ECS


  Elastic Container Service
• Launch Docker containers on AWS

  Launch ECS Tasks on ECS Clusters
• EC2 Launch Type


  • You must provision & maintain the infrastructure (the EC2 instances)
  • Each EC2 Instance must run the ECS Agent to register in the ECS Cluster
  • AWS takes care of starting / stopping containers
• Fargate Launch Type


  • You do not provision the infrastructure (no EC2 instances to manage)
  • It's all Serverless!
  • You just create task definitions
  • AWS just runs ECS Tasks for you based on the CPU / RAM you need
  • To scale, just increase the number of tasks. Simple - no more EC2 instances
• IAM Roles for ECS


  • EC2 Instance Profile (EC2 Launch Type only)
  • ECS Task Role
• EC2 Instance Profile (EC2 Launch Type only)


  • Used by the ECS agent
  • Makes API calls to ECS service
  • Send container logs to CloudWatch Logs
  • 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
• 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
  • Fargate + EFS = Serverless
  • Use cases: persistent multi-AZ shared storage for your containers
• Amazon S3 cannot be mounted as a file system
• ECS Cluster


  A logical grouping of EC2 instances or AWS Fargate tasks where you can run containerized applications
• ECS Cluster


  • Acts as the infrastructure foundation for running your containers and managing resources
  • You can have multiple clusters within an AWS account, each serving different purposes or environments
• Task (in ECS)


  A logical grouping of Docker containers that are scheduled together on the same EC2 instance or Fargate task
• Task (in ECS)


  • Tasks are the basic unit of work in ECS
  • You define tasks using task definitions