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NAME | SYNOPSIS | DESCRIPTION | CONFIGURATION DIRECTORIES AND PRECEDENCE | CONFIGURATION FILE FORMAT | SPECIFIERS | IDEMPOTENCE | SEE ALSO | NOTES | COLOPHON |
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SYSUSERS.D(5) sysusers.d SYSUSERS.D(5)
sysusers.d - Declarative allocation of system users and groups
/etc/sysusers.d/*.conf
/run/sysusers.d/*.conf
/usr/local/lib/sysusers.d/*.conf
/usr/lib/sysusers.d/*.conf
#Type Name ID GECOS Home directory Shell
u user_name uid "User Description" /home/dir /path/to/shell
u user_name uid:gid "User Description" /home/dir /path/to/shell
u user_name /file/owned/by/user "User Description" /home/dir /path/to/shell
g group_name gid
g group_name /file/owned/by/group
m user_name group_name
r - lowest-highest
systemd-sysusers uses the files from sysusers.d directory to
create system users and groups and to add users to groups, at
package installation or boot time. This tool may be used to
allocate system users and groups only, it is not useful for
creating non-system (i.e. regular, "human") users and groups, as
it accesses /etc/passwd and /etc/group directly, bypassing any
more complex user databases, for example any database involving
NIS or LDAP.
Each configuration file shall be named in the style of
package.conf or package-part.conf. The second variant should be
used when it is desirable to make it easy to override just this
part of configuration.
Files in /etc/sysusers.d override files with the same name in
/usr/lib/sysusers.d and /run/sysusers.d. Files in /run/sysusers.d
override files with the same name in /usr/lib/sysusers.d.
Packages should install their configuration files in
/usr/lib/sysusers.d. Files in /etc/sysusers.d are reserved for
the local administrator, who may use this logic to override the
configuration files installed by vendor packages. All
configuration files are sorted by their filename in lexicographic
order, regardless of which of the directories they reside in. If
multiple files specify the same path, the entry in the file with
the lexicographically earliest name will be applied. All later
entries for the same user and group names will be logged as
warnings.
If the administrator wants to disable a configuration file
supplied by the vendor, the recommended way is to place a symlink
to /dev/null in /etc/sysusers.d/ bearing the same filename.
The file format is one line per user or group containing name,
ID, GECOS field description, home directory, and login shell:
#Type Name ID GECOS Home directory Shell
u httpd 404 "HTTP User"
u _authd /usr/bin/authd "Authorization user"
u postgres - "Postgresql Database" /var/lib/pgsql /usr/libexec/postgresdb
g input - -
m _authd input
u root 0 "Superuser" /root /bin/zsh
r - 500-900
Empty lines and lines beginning with the "#" character are
ignored, and may be used for commenting.
Type
The type consists of a single letter. The following line types
are understood:
u
Create a system user and group of the specified name should
they not exist yet. The user's primary group will be set to
the group bearing the same name unless the ID field specifies
it. The account will be created disabled, so that logins are
not allowed.
Added in version 215.
g
Create a system group of the specified name should it not
exist yet. Note that u implicitly creates a matching group.
The group will be created with no password set.
Added in version 215.
m
Add a user to a group. If the user or group do not exist yet,
they will be implicitly created.
Added in version 215.
r
Add a range of numeric UIDs/GIDs to the pool to allocate new
UIDs and GIDs from. If no line of this type is specified, the
range of UIDs/GIDs is set to some compiled-in default. Note
that both UIDs and GIDs are allocated from the same pool, in
order to ensure that users and groups of the same name are
likely to carry the same numeric UID and GID.
Added in version 216.
Name
The name field specifies the user or group name. The specified
name must consist only of the characters a-z, A-Z, 0-9, "_" and
"-", except for the first character which must be one of a-z, A-Z
or "_" (i.e. numbers and "-" are not permitted as first
character). The user/group name must have at least one character,
and at most 31.
For further details about the syntax of user/group names, see
User/Group Name Syntax[1].
It is strongly recommended to pick user and group names that are
unlikely to clash with normal users created by the administrator.
A good scheme to guarantee this is by prefixing all system and
group names with the underscore, and avoiding too generic names.
For m lines, this field should contain the user name to add to a
group.
For lines of type r, this field should be set to "-".
ID
For u and g, the numeric 32-bit UID or GID of the user/group. Do
not use IDs 65535 or 4294967295, as they have special placeholder
meanings. Specify "-" for automatic UID/GID allocation for the
user or group (this is strongly recommended unless it is strictly
necessary to use a specific UID or GID). Alternatively, specify
an absolute path in the file system. In this case, the UID/GID is
read from the path's owner/group. This is useful to create users
whose UID/GID match the owners of pre-existing files (such as
SUID or SGID binaries). The syntaxes "uid:gid" and
"uid:groupname" are supported to allow creating users with
specific primary groups. The given group must be created
explicitly, or it must already exist. Specifying "-" for the UID
in these syntaxes is also supported.
For m lines, this field should contain the group name to add to a
user to.
For lines of type r, this field should be set to a UID/GID range
in the format "FROM-TO", where both values are formatted as
decimal ASCII numbers. Alternatively, a single UID/GID may be
specified formatted as decimal ASCII numbers.
GECOS
A short, descriptive string for users to be created, enclosed in
quotation marks. Note that this field may not contain colons.
Only applies to lines of type u and should otherwise be left
unset (or "-").
Home Directory
The home directory for a new system user. If omitted, defaults to
the root directory.
Only applies to lines of type u and should otherwise be left
unset (or "-"). It is recommended to omit this, unless software
strictly requires a home directory to be set.
systemd-sysusers only sets the home directory record in the user
database. To actually create the directory, consider adding a
corresponding tmpfiles.d(5) fragment.
Shell
The login shell of the user. If not specified, this will be set
to /usr/sbin/nologin, except if the UID of the user is 0, in
which case /bin/sh will be used.
Only applies to lines of type u and should otherwise be left
unset (or "-"). It is recommended to omit this, unless a shell
different /usr/sbin/nologin must be used.
Specifiers can be used in the "Name", "ID", "GECOS", "Home
directory", and "Shell" fields. An unknown or unresolvable
specifier is treated as invalid configuration. The following
expansions are understood:
Table 1. Specifiers available
┌───────────┬──────────────────┬────────────────────────┐
│ Specifier │ Meaning │ Details │
├───────────┼──────────────────┼────────────────────────┤
│ "%a" │ Architecture │ A short string │
│ │ │ identifying the │
│ │ │ architecture of │
│ │ │ the local system. │
│ │ │ A string such as │
│ │ │ x86, x86-64 or │
│ │ │ arm64. See the │
│ │ │ architectures │
│ │ │ defined for │
│ │ │ ConditionArchitecture= │
│ │ │ in systemd.unit(5) │
│ │ │ for a full list. │
├───────────┼──────────────────┼────────────────────────┤
│ "%A" │ Operating system │ The operating system │
│ │ image version │ image version │
│ │ │ identifier of the │
│ │ │ running system, as │
│ │ │ read from the │
│ │ │ IMAGE_VERSION= field │
│ │ │ of /etc/os-release. If │
│ │ │ not set, resolves to │
│ │ │ an empty string. See │
│ │ │ os-release(5) for more │
│ │ │ information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%b" │ Boot ID │ The boot ID of the │
│ │ │ running system, │
│ │ │ formatted as string. │
│ │ │ See random(4) for more │
│ │ │ information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%B" │ Operating system │ The operating system │
│ │ build ID │ build identifier of │
│ │ │ the running system, as │
│ │ │ read from the │
│ │ │ BUILD_ID= field of │
│ │ │ /etc/os-release. If │
│ │ │ not set, resolves to │
│ │ │ an empty string. See │
│ │ │ os-release(5) for more │
│ │ │ information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%H" │ Host name │ The hostname of the │
│ │ │ running system. │
├───────────┼──────────────────┼────────────────────────┤
│ "%l" │ Short host name │ The hostname of the │
│ │ │ running system, │
│ │ │ truncated at the first │
│ │ │ dot to remove any │
│ │ │ domain component. │
├───────────┼──────────────────┼────────────────────────┤
│ "%m" │ Machine ID │ The machine ID of the │
│ │ │ running system, │
│ │ │ formatted as string. │
│ │ │ See machine-id(5) for │
│ │ │ more information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%M" │ Operating system │ The operating system │
│ │ image identifier │ image identifier of │
│ │ │ the running system, as │
│ │ │ read from the │
│ │ │ IMAGE_ID= field of │
│ │ │ /etc/os-release. If │
│ │ │ not set, resolves to │
│ │ │ an empty string. See │
│ │ │ os-release(5) for more │
│ │ │ information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%o" │ Operating system │ The operating system │
│ │ ID │ identifier of the │
│ │ │ running system, as │
│ │ │ read from the ID= │
│ │ │ field of │
│ │ │ /etc/os-release. See │
│ │ │ os-release(5) for more │
│ │ │ information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%T" │ Directory for │ This is either /tmp or │
│ │ temporary files │ the path "$TMPDIR", │
│ │ │ "$TEMP" or "$TMP" are │
│ │ │ set to. (Note that the │
│ │ │ directory may be │
│ │ │ specified without a │
│ │ │ trailing slash.) │
├───────────┼──────────────────┼────────────────────────┤
│ "%v" │ Kernel release │ Identical to uname -r │
│ │ │ output. │
├───────────┼──────────────────┼────────────────────────┤
│ "%V" │ Directory for │ This is either │
│ │ larger and │ /var/tmp or the path │
│ │ persistent │ "$TMPDIR", "$TEMP" or │
│ │ temporary files │ "$TMP" are set to. │
│ │ │ (Note that the │
│ │ │ directory may be │
│ │ │ specified without a │
│ │ │ trailing slash.) │
├───────────┼──────────────────┼────────────────────────┤
│ "%w" │ Operating system │ The operating system │
│ │ version ID │ version identifier of │
│ │ │ the running system, as │
│ │ │ read from the │
│ │ │ VERSION_ID= field of │
│ │ │ /etc/os-release. If │
│ │ │ not set, resolves to │
│ │ │ an empty string. See │
│ │ │ os-release(5) for more │
│ │ │ information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%W" │ Operating system │ The operating system │
│ │ variant ID │ variant identifier of │
│ │ │ the running system, as │
│ │ │ read from the │
│ │ │ VARIANT_ID= field of │
│ │ │ /etc/os-release. If │
│ │ │ not set, resolves to │
│ │ │ an empty string. See │
│ │ │ os-release(5) for more │
│ │ │ information. │
├───────────┼──────────────────┼────────────────────────┤
│ "%%" │ Single percent │ Use "%%" in place of │
│ │ sign │ "%" to specify a │
│ │ │ single percent sign. │
└───────────┴──────────────────┴────────────────────────┘
Note that systemd-sysusers will do nothing if the specified users
or groups already exist or the users are members of specified
groups, so normally there is no reason to override sysusers.d
vendor configuration, except to block certain users or groups
from being created.
systemd(1), systemd-sysusers(8)
1. User/Group Name Syntax
https://systemd.io/USER_NAMES
This page is part of the systemd (systemd system and service
manager) project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have
a bug report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
This page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2024-06-14. (At that
time, the date of the most recent commit that was found in the
repository was 2024-06-13.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]
systemd 257~devel SYSUSERS.D(5)
Pages that refer to this page: systemd.exec(5), systemd.directives(7), systemd.index(7), systemd.system-credentials(7), systemd-sysusers(8)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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