AWS Cloud Developer Associate Certification

8. EBT- Bean Stack

1. Developers upload applications and Elastic Beanstalk handles the deployment details of capacity provisioning, load balancing, auto-scaling, and application health monitoring
2. Elastic Beanstalk automatically scales your application up and down.
3. You maintain full control of the underlying resources
4. The Managed Platform Updates feature automatically applies updates for your operating system, Java, PHP, Node.js etc
5. AWS CloudFormation is used by Elastic Beanstalk to deploy the resources

There are several layers:

1. Applications:
   1. Contain environments, environment configurations, and application versions.
   2. You can have multiple application versions held within an application

AWS Elastic Beanstalk Deployment Policies

1. All at once – Deploys the new version to all instances simultaneously
   • If the update fails, you need to roll back the changes by re-deploying the original version to all of your instances
   • No additional cost
2. Rolling – Update a batch of instances, and then move onto the next batch once the first batch healthy
   • Each batch of instances is taken out of service while the deployment takes place.
   • Not ideal for performance-sensitive systems.
   • No additional cost
3. Rolling with additional batch: Like Rolling but launches new instances in a batch ensuring that there is full availability
   • Application is running both versions simultaneously
   • Small additional cost.
   • Additional batch is removed at the end of the deployment
   • Good for production environments
4. Immutable: Launches new instances in a new ASG and deploys the version update to these instances before swapping traffic to these instances once healthy
   • New code is deployed to new instances using an ASG
   • High cost as double the number of instances running during updates
   • Great for production environments
5. Blue/green – Create a new “stage” environment and deploy updates there
   • This is not a feature within Elastic Beanstalk
   • You create a new “staging” environment and deploy updates there
   • The new environment (green) can be validated independently and you can roll back if there are issues.
   • Route 53 can be setup using weighted policies to redirect a a percentage of traffic to the staging environment.
   • Using Elastic Beanstalk, you can “swap URLs” when done with the environment test

AWS Elastic Beanstalk – .ebextensions

• Configuration files are YAML- or JSON-formatted documents with a .config file extension that you place in a folder named .ebextensions and deploy in your application source bundle.

• The option_settings section of a configuration file defines values for configuration options.
• The other sections of a configuration file (packages, sources, files, users groups, commands, container_commands, and services) let you configure the EC2 instances that are launched in your environment.

AWS Elastic Beanstalk – HTTPS

1. Can assign a server certificate to your environment’s load balancer :
   • Can be configured through the console.
   • This secures the connection between the client (app user) and the load balancer
   • The backend connections between the load balancer and EC2 are not secured.
   • You can use AWS Certificate Manager (ACM) certificates
   • Can also configure through .ebextensions:

option_settings:
aws:elbv2:listener:443:
ListenerEnabled: 'true'
Protocol: HTTPS
SSLCertificateArns: arnXXX

• For end-to-end or single instance environments, configure instances to terminate HTTPS:
  • Must be configured through .ebextensions configuration files.

AWS Elastic Beanstalk – HTTP to HTTPS Redirection

To configure HTTP to HTTPS redirection, do one of the following:

• If your environment is load balanced – Configure your load balancer to [terminate HTTPS.]
• If you’re running a single instance environment – Configure your application to terminate HTTPS connections at the instance
• Configure your Amazon Elastic Compute Cloud (Amazon EC2) instances to redirect HTTP traffic to HTTPS (platform dependent).

AWS Elastic Beanstalk and Amazon Relational Database Service (RDS)

• You can deploy Amazon RDS within an Elastic Beanstalk environment
• However, if you terminate your Elastic Beanstalk environment you also lose the database.
• For production it is preferable to create the Amazon RDS database outside of Elastic Beanstalk