Hands-On Enterprise Application Development with Python

Rolling deployments

In the rolling deployments model of deploying an application, we do not abruptly take down all the instances of the older version of the application to replace them with the newer version. Instead, we take a gradual approach of rolling out the new application version across the infrastructure.

In this process, we first launch a new instance of the upgraded application behind the Load Balancer, and once it is ready to accept the traffic, we remove the equivalent instance of the older version of the application. This process continues until all the older instances of the application have been replaced with the newer instances. The following diagram shows a representation of the Rolling deployments strategy: 

This kind of ...