systemd-userdbd.service(8) — Linux manual page


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

NAME         top

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

SYNOPSIS         top



DESCRIPTION         top

       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" 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

SEE ALSO         top

       systemd(1), nss-systemd(8), userdbctl(1),

NOTES         top

        1. JSON User Records

        2. JSON Group Record

        3. User/Group Record Lookup API via Varlink

        4. Varlink

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
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       a bug report for this manual page, see
       This page was obtained from the project's upstream Git repository
       ⟨⟩ on 2023-12-22.  (At that
       time, the date of the most recent commit that was found in the
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       (which is not part of the original manual page), send a mail to

systemd 255                                      SYSTEMD-U....SERVICE(8)

Pages that refer to this page: userdbctl(1)systemd.directives(7)systemd.index(7)nss-systemd(8)