Specified in app.yaml
instance_class: F2 automatic_scaling: min_idle_instances: 5 max_idle_instances: automatic
Is their any way out to check instance tier/class from developer console?
Only able to guess instance class from billing status costing $0.05 per hour ie F1 instance class.
On the new console https://console.cloud.google.com, go to App Engine, then Versions. Under the dropdown More Columns, select Instance Class, then the instance class column will be displayed.
I could not find a place where to check specifically the instance type.
The only way I could verify that my instance was an F2, as specified, was using a request which triggered the instance memory usage to go way over the F1 class limit, causing the instance to be terminated (which was the reason for which I configured an F2 instead of the default). After deploying the F2 config the memory usage of the running instance happily went above the F1 class limit without the instance being terminated.
The billing status info is misleading, all classes are billed in F1 "units", see the note at the end of the Instance scaling and class section:
Important: When you are billed for instance hours, you will not see any instance classes in your billing line items. Instead, you will see the appropriate multiple of instance hours. For example, if you use an F4 instance for one hour, you do not see "F4" listed, but you will see billing for four instance hours at the F1 rate.
Use the old GAE console: https://appengine.google.com/
Select the 'versions' page (in the Main section) and the instance type is displayed next to the version if it is not F1.
eg: instance_class: F2
I am unsure where/if this information appears in the new console.
来源：https://stackoverflow.com/questions/32454741/not-able-to-change-the-frontend-instance-class-in-appengine-application