1SYSTEMD-USERDBD.SERVICE(8) systemd-userdbd.service SYSTEMD-USERDBD.SERVICE(8)
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6 systemd-userdbd.service, systemd-userdbd - JSON User/Group Record Query
7 Multiplexer/NSS Compatibility
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10 systemd-userdbd.service
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12 /usr/lib/systemd/systemd-userdbd
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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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46 systemd(1), nss-systemd(8), userdbctl(1), systemd-homed.service(8)
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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 250 SYSTEMD-USERDBD.SERVICE(8)