Why GAE launched a second instance with Max Idle Instances set to 1

Question

I use Google Ap Engine with billing Status Enabled.
Idle Instances are set to : ( 1 – 1 )

And with only 2 clients on my service, sometimes I saw a second instance. The trouble is that it's take 15s to launch the new instance (spring and co..).

80Mb of memory is to hight for one instance ?
Log for new instance : /_ah/warmup 200 14580ms 0kb
The second instance disappears after a few seconds.

Why with 3-4 requests, GAE run a second instance ?? The first one do nothing (almost) !

I tried to modify "Pending Latency" without success.

A solution ? :)

Thx

Answer 1

You've asked for exactly one idle instance. When serving a request, an instance is not idle. Therefore, App Engine spins up a new instance to maintain your requested number of idle instances.