A. Use fully baked AMIs (ג€golden imagesג€) created after each successful build, creating a new Auto Scaling group, and blue/green deployments with rollbacks.
B. Use user-data scripts to configure the instance correctly on boot by installing all dependencies when needed.
C. Use an AWS Lambda function to only update the application locally on each instance, then re-attach it to the load balancer when the process complete.
D. Use AWS OpsWorks scripts to execute on reboot of each instance to install all known dependencies, then re-attach the instances to the load balancer.