The OpenStack Identity service, or Keystone, is an authentication service for the OpenStack cloud operating system that easily integrates with third-party directory services, such as Lightweight Directory Access Protocol (LDAP). Using the OpenStack Identity services, a cloud administrator can create user accounts and configure permissions to access common resources, as well as create and manage access policies for them.
The OpenStack Image service, or Glance, provides a RESTful API that enables you to manage your virtual machine images and metadata. Glance requires storage for images. In some environments using local file storage for virtual machine images is beneficial. However, in many production environments, Swift or Ceph is a better choice as a storage back end for Glance.
An infrastructure node is a physical node which runs all the services required for the cloud environment operation, lifecycle management, and monitoring.
See: Foundation node