Elastic Beanstalk

What is it?

• a PaaS that makes it easy to deploy and scale web applications
• infrastructure as code
• Managed service, uses EC2, ASG, ELB, RDS ...
  • handles capaicity provisioning, laod balancing, scaling, applicaiton health monitoring, instance configuration
  • application code is the only responsibility of the developer

Components

• Application: environments, versions, configurations
• Application Version
• Environment: collection of AWS resources running an application version (only one application version at at time)
  • Tiers: WebServer Environment Tier & Worker Environment Tier
  • multiple environments: dev, test, prod, etc...
  • Web Server Tier vs. Worker Tier
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Deployment Modes

• Single Instance: for dev
• HA with LoadBalancer: for prod

Deployment Options for Updates

• All at once: downtime
• Rolling
• Rolling with additional batches: new instances in the same ASG
• Immutable: complete new deployment with a new ASG
• Blue Green: complete new environment
• Traffic Splitting: canary testing, small % of traffic to new deployment

WebServer vs Worker Environment

• if your app performs tasks that are long to complete, offllad these tasks to a dedicated worker environment, this Decoupling of apps into two tiers is common
• ex). processing a video, generating a zip file, etc
• supports cron.yaml

Notifications

• create rules in EventBridge to act to the following events
  • Environment operations status: create, udpate, terminate (start, success, fail)
  • Other resources status: ASG, ELB, EC2 instance (created, deleted)
  • Managed updates status: started, failed
  • Environment health status
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