Kanboard is a free, open-source, self-hosted project management tool designed for minimalism and efficiency using the Kanban methodology. It features a drag-and-drop web interface for visualizing tasks, setting work-in-progress (WIP) limits, and automating workflows. It is lightweight, allows for task, subtask, and comment tracking, and is highly customizable with plugins. 

Add these to the Kanboard config.php

define('LDAP_AUTH', true);
define('LDAP_SERVER', 'ldap://ldap-server.com:389');
define('LDAP_SSL_VERIFY', true);
define('LDAP_START_TLS', false);

define('LDAP_USERNAME_CASE_SENSITIVE', false);
define('LDAP_USER_CREATION', true);

define('LDAP_BIND_TYPE', 'user');
define('LDAP_USERNAME', 'uid=%s,ou=people,dc=example,dc=com');
define('LDAP_PASSWORD', null);

define('LDAP_USER_BASE_DN', 'ou=people,dc=example,dc=com');

define('LDAP_USER_FILTER', '(&(uid=%s)(memberof=cn=kanboard_users,ou=groups,dc=example,dc=com))');
define('LDAP_USERNAME_CASE_SENSITIVE', false);

define('LDAP_USER_ATTRIBUTE_USERNAME', 'uid');
define('LDAP_USER_ATTRIBUTE_FULLNAME', 'cn');
define('LDAP_USER_ATTRIBUTE_EMAIL', 'mail');
define('LDAP_USER_ATTRIBUTE_GROUPS', 'memberof');
define('LDAP_USER_ATTRIBUTE_PHOTO', 'jpegPhoto');
define('LDAP_USER_ATTRIBUTE_LANGUAGE', '');

Make sure you adapt the constant LDAP_SERVER to the correct LDAP endpoint. 

You also have to change dc=example,dc=com to whatever your OpenLDAP is handling, and change the kanboard_users group name used in LDAP_USER_FILTER to identify users of a valid group of yours. 

More information on setting up OpenLDAP with Kanboard can be found here.