Understanding GAE active vs created instances & pricing

[Alex Fox]

Hi,

I'm trying to get my head round how I can reduce my GAE costs, but I am having a hard time understanding the usage / instances graphs. In the attached graph can anyone tell me what, Active, Billed Instance Estimate and Created mean? It appears that my Active is pretty much always 0, so I don't really understand what that means as my monthly bill is quite high!

Also, how am I meant to understand the Utilization graph to influence the number of max_instances I set in my app.yaml?

Any other cost saving / usage debugging tips are also very welcome!

Thanks,

Alex

[yananc]

Hi Alex,

The thread provides detailed explanations on Active, Billed Instance Estimate and Created. 

Basically, Automatic scaling will start and stop instances based on the application requirements. You will not be charged for ‘Created’ instances that have been idle for 15 minutes, neither for any ‘Created’ instances exceeding the amount of ‘max_idle_instances’. Hence ‘Billed Instance Estimate’ represents the number of instances since they become ‘Active’ till 15 mins after the last request has finished processing. It also explains why this metric stands while ‘Active’ is sometimes 0.

‘Billed Instance Estimate’ will also include the number of ‘min_idle_instances’ configured in the app.yaml. Please note that the metric reading is just a rough estimate based on averages and the actual usage will be reflected on your bills. 

'Max_instances' is used for automatic_scaling to specify the maximum number of instances to create for the module version in App Engine. While Utilization measures the duration that the current request has spent so far processing the request within the App Engine (link). There is no direct influence one way or another between the two metrics.

I suggest to go over the doc for configuration and resource allocation proper to your use case, in order to provide performance in a cost-efficient manner.

Hope it helps.