Hi Yitao, CloudStack scheduling policies are implemented by the DeploymentPlanner and HostAllocator/StoragePoolAllocator components. If you want to take a look at the source code of these components, this will tell you where to look: https://cwiki.apache.org/confluence/display/CLOUDSTACK/VM+Deployment+Planning+and+Resource+Allocation
These components implement the Adapter interface of CloudStack - so you can provide your own implementation and plug it in to be used for VM deployment. Let me know if you face any questions on this. Thanks, Prachi -----Original Message----- From: Yitao Jiang [mailto:willier...@gmail.com] Sent: Thursday, November 21, 2013 10:11 PM To: dev@cloudstack.apache.org Subject: Help In Launch instance Schedule policy Hi, I was looking for some help in launching instance using some schedule policies. I know that Openstack allow developers write their own policy .So I guess cloudstack support maybe that .Since i am just started developing it , i'll be really appreciate someone can tell me where i can write it using some policy, such as according to the weight of each host, or RoundRobin. -- Best regards, Yitao Jiang
