Azure Active Directory Cloud Sync is a software that synchronizes objects from Active Directory to Azure Active Directory.
Azure AD Connect cloud synchronization orchestrates the provisioning of AD objects to Azure AD in Microsoft Online Services. Locally only a simple agent is needed.
The entire synchronization configuration is set up in the Azure Portal (https://portal.azure.com). Azure AD Cloud Sync supports high availability by installing the agent on multiple servers.
This tutorial describes how to install and configure Azure AD Cloud Sync.