This template provisions a highly available base ArcGIS Enterprise deployment on two AWS instances plus one instance for a file server. A base ArcGIS Enterprise deployment includes Portal for ArcGIS, a GIS Server (used as the portal's hosting server), ArcGIS Data Store (which will create a relational and tile cache data store), and ArcGIS Web Adaptor. You can optionally direct the template to create a spatiotemporal big data store on additional instances. The template will set up an architecture as shown in the graphic below.
After the stack is created successfully, the output of this stack has the URLs to ArcGIS Server Manager and REST page using your domain name. There's also an output for the Elastic Load Balancer (ELB) created in front of this deployment. You need to map your domain name to the ELB. For example, map
arcgis-WebGISha-123456789.us-east-1.elb.amazonaws.com through CNAME mapping.
See Troubleshoot AWS CloudFormation stack creation in the ArcGIS Enterprise on Amazon Web Services help if you run into problems.