Comment by samah for Ceilometer (in the past, now it's actually Aodh) calls whatever URL you ask it to. The URL that the Heat autoscaling resources provide (via the signal_url attribute) is for the resource signal API.

Is there an example with Aodh alarm or I just need to change Ceilometer alarm with it, my goal is to use backend api for autoscaling that's why i'm asking and thank you so much for your reply :)