Elastic Beanstalk¶

Overview¶

• Developer centric view of deploying apps on AWS.
• Uses EC2, ASG, ELB, RDS etc.
• Free, but pay for underlying resources.
• Handles instance & OS configuration.
• Provides a deployment strategy.
• Developer only responsible for application code.
• Has a rollback feature to rollback to previous application version.
• By default doesn't persist storage.
• Self-signed certificate used for HTTPS if a custom domain isn't purchased.
• Supports TCP pass-through.
• Store SSL private keys on S3 and download them from there.
• If doing HTTP to HTTPS redirect, ensure the health check can still run over HTTP.

Three Architectural Models¶

• Single Instance Deployment: Good for development
• LB + ASG: Good for production or pre-production web applications.
• ASG Only: Good for non-web applications in production (workers etc)

Three Components¶

Application¶

• Collection of Elastic Beanstalk components (environments, versions, environment configurations).

Application Version¶

• Tag that points to an S3 object containing the deployable code (war file etc).

Environment¶

• Collection of AWS resources running an application version.
• Elastic Beanstalk will provision the AWS resources needed to run the application version (EC2 instances, ASG etc).
• Use Environment Links to split components between multiple environments, and link them together to share information.
• Uses Route53 to generate the environments CNAME.
• Does SSL termination at the load balancer by default, but can be configured to use SSL all the way to the EC2 instance.
• Use ACM, or IAM to distribute SSL certificate.
• Add a HTTPS listener under .ebextensions/securelistener-[clb|alb|nlb].config.

Worker Environment Tier¶

• Uses SQS to pass off long-running tasks to a back-end.
• Scheduled tasks can be setup using cron.
• Failed tasks will be re-queued after the ErrorVisibilityTimeout period.
• Unresponsive tasks will be re-queued after the InactivityTimeout period.
• Supports Dead Letter Queues.
• Auto-scales via CloudWatch.
• Use MaxRetries to limit how many times the message is re-queued.

Web Environment Tier¶

• Front-end handling incoming requests (ie: web server).
• Requests come into the web environment tier, put tasks in an SQS queue, which will read the tasks from the SQS queue.

Container Type¶

• Defines the infrastructure toplogy, and software stack running on the EC2 instances. eg: LAMP, Tomcat.

Host Manager¶

• Runs on each EC2 instance.
• Deploy the application.
• Aggregates events/metrics.
• Monitors application logs for errors.
• Patches components.
• Handles log rotation and logging to S3.

Environment Lifecycle¶

1. Create application.
2. Create environments.
3. Upload an application version (+ alias)
4. Release to environments.

Supported Languages¶

• Go, Java, Tomcat, .NET, NOdeJS, PHP, Python, Ruby, Packer, Docker (Single/Multi container), Preconfigured Docker, custom platform.

Deployment Modes¶

Single instance¶

• Good for development.
• 1 EC2 instance, 1 ElasticIP, 1 ASP etc, 1 AZ.

High Availability with Load Balancer¶

• Good for production.
• Multi-AZ, multiple EC2 instances, multiple ASGs, multi-AZ RDS etc.

Deployment Policies¶

All at once¶

• Fastest, but deploys to all instances so generates downtime.

Rolling¶

• Update a few instances at a time (bucket).
• Application runs at partial capacity.
• Can control the bucket size.
• Both versions of the application are running at the same time for a period of time.
• Long deployment times.

Rolling with additional batches¶

• Similar to rolling, but spins up new instances to move the batch (spin up X new instances, wait till healthy, discard X old instances, move on to the next batch).
• Application always runs at full capacity.
• Can control the bucket size.
• Both versions of the application are running at the same time for a period of time.
• There is additional cost due to the extra batch, that gets discarded at the end of the update.
• Good for production.

Immutable¶

• Spins up new instances in a new (temporary) ASG, and once they're healthy, moves the instances into the current ASG. Once health checks pass, the old instances are released.
• High cost because you're running at double capacity for a while.
• Has the longest deployment time.
• Enables fast rollback by terminating the new ASG.
• Good for production.
• No downtime.

Traffic Splitting¶

• Perform canary testing as part of the deployment.
• Spins up new instances similar to an Immutable Deployment, then sends a percentage of traffic to the new instances for a specific amount of time. If health checks pass, all traffic is migrated. If health check fails, canaries are terminated, and traffic is sent back to the original instances.

Blue/Green¶

• Not a feature of Beanstalk.
• Zero downtime
• Create a new environment, and deploy the new version there.
• Can use Route53 to setup weighted policies to move some load over.
• Using Beanstalk, you'd swap the URLs once environment testing is finished (does a CNAME update via Route53)
• Is a very manual process

Elastic Beanstalk CLI¶

• Additional CLI that makes working with elastic beanstalk easier.
• Common commands
• eb create
• eb status
• eb health
• eb events
• eb logs
• eb open
• eb deploy
• eb config
• eb terminate

Deployment Process¶

• Define dependencies (requirements.txt, package.json etc)
• Package code as a zip file
• Upload zip to Elastic Beanstalk to create the app version.
• Deploy the new app version to an environment.
• Elastic Beanstalk will deploy the zip to the EC2 instances, resolve dependencies & start the application.

Elastic Beanstalk Lifecycle Policy¶

• Maximum of 1,000 application versions.
• Removes old versions of the application.
• Can be based on time (days), or space (number of versions).
• Versions in active use won't be deleted.
• There's an option to not delete the source bundle in S3 to prevent data loss.
• Need to specify the IAM role that allows Elastic Beanstalk to remove the old application version & associated files.

Elastic Beanstalk Extensions¶

• .ebextensions folder that defines additional configurations for Elastic Beanstalk.
• Must in yaml/json format.
• File exention ends in .config (eg: logging.config)
• Can set default settings using option_settings
• Add additional resources like RDS, ElastiCache etc.
• Anything managed by .ebextensions will be discarded when the environment is terminated.

CloudFormation¶

• Elastic Beanstalk relies on CloudFormation.
• Can define CloudFormation resources in .ebextensions to configure basically anything.

Cloning¶

• Existing environment can be cloned into a new environment.
• All resources and config are preserved (RDS data isn't).

Beanstalk Migrations¶

Loadbalancer¶

• Create a new environment, with the same configure, but without the Load Balancer (can't use clone).
• Deploy the application into the new environment.
• Do a CNAME swap/Route53 to swap the environments.

Decoupling RDS¶

• Create a RDS snapshot.
• Protect RDS database from deletion in the RDS console.
• Create a new environment without RDSs, and point the application to the existing RDS.
• Do a CNAME swap/Route53 update to move traffic over.
• Terminate the old environment.
• Termination protection will prevent the RDS from being removed.
• Delete the CloudFormation stack because it will be stuck in DELETE_FAILED state.

Single Docker¶

• Provide a Dockerfile to build and run the docker container, or
• A Dockerrun.aws.json that describes where the already built docker image is
• Doesn't use ECS.

Multi-Container Docker¶

• Uses ECS.
• Provide a Dockerrun.aws.json at the root of the source code.
• Generates the ECS task definition.
• Docker images must already be built.

HTTPS¶

Beanstalk with HTTPS¶

• Load the SSL cert onto the load balancer
• Do it from the EB console.
• Do it in code using .ebextensions/securelistener-alb.confg.
• SSL cert can be provisioned via ACM or CLI.
• Need to configure the SG to allow inbound HTTPS traffic.

Beanstalk with HTTPS redirect¶

• Configure instances to do HTTP => HTTPS redirect.
• Configure ALB to do the redirect.
• Make sure health checks aren't redirected.

Custom Platform¶

• Define from scratch OS, additional software and scripts that run.
• Only use case is when the application language doesn't use docker or is incompatible with EB.
• Use platform.yaml to define the AMI.
• Use packer to generate the AMI.

Monitoring¶

• Monitor CPU/Network utilization, response time, total request count via the Elastic Beanstalk console.
• ELB and EC2 instance metrics are enabled for all environments (sent every 5mins).
• Enabled Enhanced Health to get additional metrics, such as severity of the health problem. Also enables the Health page. Metrics are sent every 10secs.
• Health agent runs on each EC2 instance to monitor web server logs and system metrics.