Maybe someone else could speak to it in more detail.
A few months back I set up a simple infrastructure for UiPath using AWS Cloudformation.
It consists of RDS for the SQL Server, an EC2 instance for Orchestrator (2018.3.1) Platform, and multiple EC2 instances for each robot, with a partially built custom AMIs for Orchestrator and Robot and a bit of Cfn-Init scripting for some of the software installation and environmental configuration changes.
Originally I did have a Network Load balancer in front of Orchestrator with the eventual plan to have a balanced node with Redis to keep the master and slaves in sync, but this complicated the deployment with Cloudformation due to the installation steps of Orchestrator and the changes required to make to set up the additional slave instances.
As we don’t currently have a need for additional nodes (Running very minimal robots at the moment), I removed the NLB and Redis from the design to meet timelines.
Out of curiosity, what is your scenario where you would want to have auto-scaling for the Orchestrator nodes and/or Robots?
From what I’ve learned so far, it would be a matter of creating some deployment/build scripts, probably prepare some custom AMIs (Either one for Master and one for the slaves, or a common AMI that would make the required configuration changes programmatically) to minimize the bootup time required by the auto-scaling group.