SYSTEMD-USERDBD.SERVICE(8)  systemd-userdbd.service SYSTEMD-USERDBD.SERVICE(8)

NAME
       systemd-userdbd.service, systemd-userdbd - JSON User/Group Record Query
       Multiplexer/NSS Compatibility

SYNOPSIS
       systemd-userdbd.service

       /usr/lib/systemd/systemd-userdbd

DESCRIPTION
       systemd-userdbd is a system service that multiplexes user/group lookups
       to all local services that provide JSON user/group record definitions
       to the system. In addition it synthesizes JSON user/group records from
       classic UNIX/glibc NSS user/group records in order to provide full
       backwards compatibility. It may also pick up statically defined JSON
       user/group records from files in /etc/userdb/, /run/userdb/,
       /run/host/userdb/ and /usr/lib/userdb/ with the ".user" or ".group"
       extension.

       Most of systemd-userdbd's functionality is accessible through the
       userdbctl(1) command.

       The user and group records this service provides access to follow the
       JSON User Records[1] and JSON Group Record[2] definitions. This service
       implements the User/Group Record Lookup API via Varlink[3], and
       multiplexes access other services implementing this API, too. It is
       thus both server and client of this API.

       This service provides three distinct Varlink[4] services:
       io.systemd.Multiplexer provides a single, unified API for querying JSON
       user and group records. Internally it talks to all other user/group
       record services running on the system in parallel and forwards any
       information discovered. This simplifies clients substantially since
       they need to talk to a single service only instead of all of them in
       parallel.  io.systemd.NameServiceSwitch provides compatibility with
       classic UNIX/glibc NSS user records, i.e. converts struct passwd and
       struct group records as acquired with APIs such as getpwnam(1) to JSON
       user/group records, thus hiding the differences between the services as
       much as possible.  io.systemd.DropIn makes JSON user/group records from
       the aforementioned drop-in directories available.

SEE ALSO
       systemd(1), nss-systemd(8), userdbctl(1), systemd-homed.service(8)

NOTES
	1. JSON User Records
	   https://systemd.io/USER_RECORD

	2. JSON Group Record
	   https://systemd.io/GROUP_RECORD

	3. User/Group Record Lookup API via Varlink
	   https://systemd.io/USER_GROUP_API

	4. Varlink
	   https://varlink.org/

systemd 258					    SYSTEMD-USERDBD.SERVICE(8)