sysusers.d
systemd
Developer
Lennart
Poettering
lennart@poettering.net
sysusers.d
5
sysusers.d
Declarative allocation of system users and groups
/usr/lib/sysusers.d/*.conf
Description
systemd-sysusers uses the
files from /usr/lib/sysusers.d/
to create system users and groups at package
installation or boot time. This tool may be used for
allocating system users and groups only, it is not
useful for creating non-system users and groups, as it
accessed /etc/passwd and
/etc/group directly, bypassing
any more complex user database, for example any
database involving NIS or LDAP.
File Format
Each file shall be named in the style of
package.conf.
All files are sorted by their filename in
lexicographic order, regardless of which of the
directories they reside in. If multiple files specify
the same user or group, the entry in the file with the
lexicographically earliest name will be applied, all
all other conflicting entries will be logged as
errors. Users and groups are
processed in the order they are listed.
The file format is one line per user or group
containing name, ID and GECOS field description:
# Type Name ID GECOS
u httpd 440 "HTTP User"
u authd /usr/bin/authd "Authorization user"
g input - -
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. The
user's shell will be set to
/sbin/login,
the home directory to
/. The
account will be created
disabled, so that logins are
not allowed.
g
Create a
system group of the specified
name should it not exist
yet. Note that
u
implicitly create a matching
group. The group will be
created with no password
set.
Name
The name field specifies the user or
group name. It should be be shorter than 256
characters and avoid any non-ASCII characters,
and not begin with a numeric character. 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.
ID
The numeric 32bit 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. 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).
GECOS
A short, descriptive string for users to
be created, enclosed in quotation marks. Note
that this field may not contain colons.
See Also
systemd1,
systemd-sysusers8