How can make openvidu community scalable using aws and also i want to enhance openvidu community so any doc for openvidu server development.
Scalability is offered in OpenVidu Pro. But of course you can change OpenVidu Server CE as you wish: https://openvidu.io/docs/developing/
(Besides you will have to use kurento-java nightly right now to compile openvidu parent repository. Add it like this: https://doc-kurento.readthedocs.io/en/latest/user/installation_dev.html#kurento-java-client)
See the documentation about the promonitoring dashboard here.
https://openvidu.io/docs/openvidu-pro/detailed-session-monitoring/
It would be good to have a basic dashboard for the opensource version 
how can connect two or more kms server with one openvidu server
That capability is not available in CE version, only in the PRO version.
any documentation of openvidu CE core server ?
You can visit OpenVidu github repository.