openldap package default config won't work
When installing openldap it defaults to using mdb via this line in the config
in the /etc/openldap/slapd.conf file. However by default openldap-back-mdb is not installed when installing openldap. If the user were to install this backend package, the config still doesn't work because the bdb module installed is an so module - usr/lib/openldap/back_mdb.so .
So assuming we want openldap to work when installed, a default backend database module needs to be installed. Since even installing the default mdb module fails with an error, at a minimum, moduleload should call back_mdb.so not .la. I think a somewhat consistent solution to the issue is to not provide /etc/openldap/slapd.conf at all. Instead provide /etc/openldap/slapd.conf.sample which makes it clear that this is a file that needs to be modified. (still call the .so in the sample config though)
I am not familiar with alpine packaging policies. Perhaps a check+warning in the init script might work too. Though people may call slapd directly.
Please do let me know if further info is needed.
EDIT: I noticed something else. Tacking it on here. slapd.conf has 'pidfile /var/lib/openldap/run/slapd.pid' and 'argsfile /var/lib/openldap/run/slapd.args' but /var/lib/openldap/run does not exist.