GAE Python - Some performance settings must be changed via Module configuration files

Question

I've migrated my app to using modules instead of backends. To do so, I followed the instructions on this page: https://developers.google.com/appengine/docs/python/modules/

For some reason however, when I go to the App Engine Dashboard and then to Administration > Application Settings, the following notification is shown under Performace:

Some performance settings must be changed via Module configuration files. See the Modules documentation for more information

With the notification there is a link included which leads to the page I posted above.

The top of my app.yaml looks as follows (and therefore should take default settings):

application: myapp
version: uno
runtime: python27
api_version: 1
threadsafe: true

And the top of my module looks as follows:

application: myapp
module: tasks
version: uno
runtime: python27
api_version: 1
threadsafe: true
instance_class: B4
basic_scaling:
  max_instances: 1
  idle_timeout: 10m

What performance settings is the notification referring to?

Answer 1

It's referring to the scaling options under Configuration on the modules documentation page you've linked to.

If you don't have modules (or rather just have one, with the default auto-scaling using just app.yaml) then the Application Settings page has sliders you can use to control the instance-class, the max- and min-pending-latency and the min- and max-idle-instances. For multiple modules, you need to put this configuration in the yaml files - as you've done for your tasks module. (You can potentially have lots of modules - having sliders for each of them would make that page very confusing.)

When it says "must be changed", it doesn't mean that you must make changes, just that if you do want to make changes, you have to do it via the yaml files and not via that page.