Elastic Beanstalk Deployment Modes¶

Deployment Options for Updates¶

All at once (deploying all in one go) - fastest, but instances aren't available to serve traffic for a bit (downtime)
Rolling: update a few instances at a time (bucket), and then move onto the next bucket once the first bucket is healthy
Rolling with additional batches: like rolling, but spins up new instances to move the batch (so that the old application is still available)
Immutable: spins up new instances in a new ASG, deploys version to these instances, and then swaps all the instances when everything is healthy

Not a direct feature of Elastic Beanstalk
Zero downtime and realease facility
Create a new stage environment and deploy v2 there
The new environment (green) can be validated independently and roll back if there are issues
Route 53 can be setup using weighted policies to redirect a little bit of traffic to the stage environment
Using Beanstalk, "swap URLs" when done with the environment test

New application version is deployed to a temporary ASG with the same capacity
A small % of the traffic is sent to the temporary ASG for configurable amount of time
Deployment health is monitored
If there's a deployment failure, this triggers and automated rollback.
No application downtime
New instances are migrated from the temporary to the original ASG
Old application version is teminated

https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/using-features.deploy-existing-version.html