问题
Do I need to pay to for a resident instance? The information available is confusing to me? I want to enable the "always on" feature for my java app. Thanks.
回答1:
You do need to pay for a resident instance - just set the number of minimum idle instances to however many resident instances you want (3 is similar to the "Always On" feature). Some info about idle instances from the Applications page (where you set it):
The Idle Instances slider allows you to control the number of idle instances available to the default version of your application at any given time. Idle Instances are pre-loaded with your application code, so when a new Instance is needed, it can serve traffic immediately. You will not be charged for idle instances over the specified maximum. A smaller number of idle Instances means your application costs less to run, but may encounter more startup latency during load spikes.
回答2:
You need to look into backends, where you control the startup and shutdown of the instance. backends cost from 0.08$ to $0.64 per hours depending on you backend type.
回答3:
Setting the minimum idle instances (resident instances) is, by default, disabled. Resident instances are available to paid apps only. You must therefore enable billing. For that GAE will need to store your credit card information.
来源：https://stackoverflow.com/questions/8131575/how-do-i-make-a-resident-instance-in-google-app-engine