389-ds-base binary package in Ubuntu Oracular amd64

 Based on the Lightweight Directory Access Protocol (LDAP), the 389
 Directory Server is designed to manage large directories of users and
 resources robustly and scalably.
 .
 Its key features include:
  * four-way multi-master replication;
  * great scalability;
  * extensive documentation;
  * Active Directory user and group synchronization;
  * secure authentication and transport;
  * support for LDAPv3;
  * graphical management console;
  * on-line, zero downtime update of schema, configuration, and
    in-tree Access Control Information.

Source package