Frentix offers an easy to install LDAP plugin for OLAT 6.0. The plugin has the following features:

• Bulk user import / synchronization from the LDAP directory both as one-time jobs or as a scheduled recurrent operation (configurable, can be disabled). Synchronizaton can also be started from the GUI.
  
• On-the-fly user generation on first user login (alternative to configuration above)
• Login and real-time authentication agains the LDAP directory
• Caching of LDAP password to protect OLAT from tremporarily LDAP downtime (configurable, can be disabled)
• Migrating of existing OLAT users with LDAP users (configurable, can be disabled)
• Mapping of LDAP attributes to OLAT user properties (configurable)
• Support for multiple LDAP bases to define which user groups shold be synchronized / are allowed to log in (configurable)
• Support for various LDAP servers including Microsoft Active Directory

This is a commercial plugin, please get in contact to get more information.