1SYSTEMD-USERDBD.SERVICE(8)  systemd-userdbd.service SYSTEMD-USERDBD.SERVICE(8)
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NAME

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

10       systemd-userdbd.service
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12       /usr/lib/systemd/systemd-userdbd
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DESCRIPTION

15       systemd-userdbd is a system service that multiplexes user/group lookups
16       to all local services that provide JSON user/group record definitions
17       to the system. In addition it synthesizes JSON user/group records from
18       classic UNIX/glibc NSS user/group records in order to provide full
19       backwards compatibility. It may also pick up statically defined JSON
20       user/group records from drop-in files in /etc/userdb/, /run/userdb/,
21       /run/host/userdb/ and /usr/lib/userdb/.
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23       Most of systemd-userdbd's functionality is accessible through the
24       userdbctl(1) command.
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26       The user and group records this service provides access to follow the
27       JSON User Records[1] and JSON Group Record[2] definitions. This service
28       implements the User/Group Record Lookup API via Varlink[3], and
29       multiplexes access other services implementing this API, too. It is
30       thus both server and client of this API.
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32       This service provides three distinct Varlink[4] services:
33       io.systemd.Multiplexer provides a single, unified API for querying JSON
34       user and group records. Internally it talks to all other user/group
35       record services running on the system in parallel and forwards any
36       information discovered. This simplifies clients substantially since
37       they need to talk to a single service only instead of all of them in
38       parallel.  io.systemd.NameServiceSwitch provides compatibility with
39       classic UNIX/glibc NSS user records, i.e. converts struct passwd and
40       struct group records as acquired with APIs such as getpwnam(1) to JSON
41       user/group records, thus hiding the differences between the services as
42       much as possible.  io.systemd.DropIn makes JSON user/group records from
43       the aforementioned drop-in directories available.
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SEE ALSO

46       systemd(1), nss-systemd(8), userdbctl(1), systemd-homed.service(8)
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NOTES

49        1. JSON User Records
50           https://systemd.io/USER_RECORD
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52        2. JSON Group Record
53           https://systemd.io/GROUP_RECORD
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55        3. User/Group Record Lookup API via Varlink
56           https://systemd.io/USER_GROUP_API
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58        4. Varlink
59           https://varlink.org/
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63systemd 254                                         SYSTEMD-USERDBD.SERVICE(8)
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