App Engine is a managed service that takes care of
instance VM scaling for you. When more traffic hits your application, App Engine will automatically copy your application to new VMs and route traffic to them. App Engine will also turn down VMs when traffic slows down in order to save you money. You can change your
scaling settings to best fit your traffic patterns using the
app.yaml configuration file.
Additionally, you can deploy multiple independent
services with their own code using the
'gcloud app deploy ~/my_app/app.yaml' command, and App Engine will scale and route traffic to them for you. Just ensure you name the different '
service' in your app.yaml to tell gcloud what service to deploy your code to.