Autoscaling queued

Hello,

I am testing the docker-autoscaler executor with the following configuration:

concurrent = 30 # must match max_instance * capacity per instance

executor = "docker-autoscaler"

plugin = "azure:1.0.0" ## i have also try the 0.3.0 version

capacity_per_instance = 1 # max one job per vm

max_use_count = 1 # use the vm only for one job and destroy it

max_instances = 30 # max vm running

idle_count = 1 # keep 1 vm constantly runnning even with no jobs

idle_time = "20m0s"

My problem is the following: when I run a pipeline with multiple jobs (say 15), I except that the runner will create 15 VMs on my VMSS on azure at the same time, but in fact, one vm at a time is created, when one VM finish the creation, the next one is created, so with 15 jobs (and capacity_per_instance = 1) the last jobs has to wait 14 Vms creation to start (approx. queued 3-4 minutes).

I would like to know if this behavior is excepted or if I have a misconfiguration somewhere.

I already taked a look on Azure side, zero rate limit found and I can create 15 Vms concurrently with Azure cli. I have tried to specify burst and limit in the config too, even if the default seem to be sufficient for my needs.

Thank you for your help.