Here is the debug log output of centos when the slapd service is atsrted :
ldap_url_parse_ext(ldap:///) 60bb6b53 daemon: listener initialized ldap:/// 60bb6b53 daemon_init: 2 listeners opened 60bb6b53 slapd init: initiated server. 60bb6b53 mdb_back_initialize: initialize MDB backend 60bb6b53 mdb_back_initialize: LMDB 0.9.25: (January 30, 2020) 60bb6b53 backend_startup_one: starting "cn=config" 60bb6b53 ldif_read_file: read entry file: "/etc/ldap/sns/slapd.d//cn=config.ldif" 60bb6b53 => str2entry: "# AUTO-GENERATED FILE - DO NOT EDIT!! Use ldapmodify.
Here is the debug log output of Alpine when the slapd service is started :
ldap_url_parse_ext(ldap:///) 60bb70ac daemon: listener initialized ldap:/// 60bb70ac daemon_init: 2 listeners opened ldap_create 60bb70ac slapd init: initiated server. 60bb70ac slap_sasl_init: initialized! 60bb70ac backend_startup_one: starting "cn=config" 60bb70ac ldif_read_file: read entry file: "/etc/ldap/sns/slapd.d//cn=config.ldif" 60bb70ac => str2entry: "# AUTO-GENERATED FILE - DO NOT EDIT!! Use ldapmodify.
clearly backend ldap configuration is missing in Alpine, not sure how to initialize the same ? I tired loading the modules in slapd.ldif after this slaptest initializes the backend mdb and test is successful in alpine, but the same (back_mdb) is not configured while starting the slapd services.