The following options control various properties of the user
records/home directories that systemd-homed.service manages.
These switches may be used in conjunction with the create and
update commands for configuring various aspects of the home
directory and the user account:
--real-name=NAME, -c NAME
The real name for the user. This corresponds with the GECOS
field on classic UNIX NSS records.
--realm=REALM
The realm for the user. The realm associates a user with a
specific organization or installation, and allows
distinguishing users of the same name defined in different
contexts. The realm can be any string that also qualifies as
valid DNS domain name, and it is recommended to use the
organization's or installation's domain name for this
purpose, but this is not enforced nor required. On each
system only a single user of the same name may exist, and if
a user with the same name and realm is seen it is assumed to
refer to the same user while a user with the same name but
different realm is considered a different user. Note that
this means that two users sharing the same name but with
distinct realms are not allowed on the same system. Assigning
a realm to a user is optional.
--email-address=EMAIL
Takes an electronic mail address to associate with the user.
On log-in the $EMAIL environment variable is initialized from
this value.
--location=TEXT
Takes location specification for this user. This is free-form
text, which might or might not be usable by geo-location
applications. Example: --location="Berlin, Germany" or
--location="Basement, Room 3a"
--icon-name=ICON
Takes an icon name to associate with the user, following the
scheme defined by the Icon Naming Specification
--home-dir=PATH, -dPATH
Takes a path to use as home directory for the user. Note that
this is the directory the user's home directory is mounted to
while the user is logged in. This is not where the user's
data is actually stored, see --image-path= for that. If not
specified defaults to /home/$USER.
--uid=UID
Takes a preferred numeric UNIX UID to assign this user. If a
user is to be created with the specified UID and it is
already taken by a different user on the local system then
creation of the home directory is refused. Note though, if
after creating the home directory it is used on a different
system and the configured UID is taken by another user there,
then systemd-homed may assign the user a different UID on
that system. The specified UID must be outside of the system
user range. It is recommended to use the 60001...60513 UID
range for this purpose. If not specified, the UID is
automatically picked. If the home directory is found to be
owned by a different UID when logging in, the home directory
and everything underneath it will have its ownership changed
automatically before login completes.
Note that users managed by systemd-homed always have a
matching group associated with the same name as well as a GID
matching the UID of the user. Thus, configuring the GID
separately is not permitted.
--member-of=GROUP, -G GROUP
Takes a comma-separated list of auxiliary UNIX groups this
user shall belong to. Example: --member-of=wheel to provide
the user with administrator privileges. Note that
systemd-homed does not manage any groups besides a group
matching the user in name and numeric UID/GID. Thus any
groups listed here must be registered independently, for
example with groupadd(8). Any non-existent groups are
ignored. This option may be used more than once, in which
case all specified group lists are combined. If the user is
currently a member of a group which is not listed, the user
will be removed from the group.
--skel=PATH
Takes a file system path to a directory. Specifies the
skeleton directory to initialize the home directory with. All
files and directories in the specified path are copied into
any newly create home directory. If not specified defaults to
/etc/skel/.
--shell=SHELL
Takes a file system path. Specifies the shell binary to
execute on terminal logins. If not specified defaults to
/bin/bash.
--setenv=VARIABLE[=VALUE]
Takes an environment variable assignment to set for all user
processes. May be used multiple times to set multiple
environment variables. When "=" and VALUE are omitted, the
value of the variable with the same name in the program
environment will be used.
Note that a number of other settings also result in
environment variables to be set for the user, including
--email=, --timezone= and --language=.
--timezone=TIMEZONE
Takes a time zone location name that sets the timezone for
the specified user. When the user logs in the $TZ environment
variable is initialized from this setting. Example:
--timezone=Europe/Amsterdam will result in the environment
variable "TZ=:Europe/Amsterdam". (":" is used intentionally
as part of the timezone specification, see tzset(3).)
--language=LANG
Takes a specifier indicating the preferred language of the
user. The $LANG environment variable is initialized from this
value on login, and thus a value suitable for this
environment variable is accepted here, for example
--language=de_DE.UTF8.
--ssh-authorized-keys=KEYS
Either takes a SSH authorized key line to associate with the
user record or a "@" character followed by a path to a file
to read one or more such lines from. SSH keys configured this
way are made available to SSH to permit access to this home
directory and user record. This option may be used more than
once to configure multiple SSH keys.
--pkcs11-token-uri=URI
Takes an RFC 7512 PKCS#11 URI referencing a security token
(e.g. YubiKey or PIV smartcard) that shall be able to unlock
the user account. The security token URI should reference a
security token with exactly one pair of X.509 certificate and
private key. A random secret key is then generated, encrypted
with the public key of the X.509 certificate, and stored as
part of the user record. At login time it is decrypted with
the PKCS#11 module and then used to unlock the account and
associated resources. See below for an example how to set up
authentication with a security token.
Instead of a valid PKCS#11 URI, the special strings "list"
and "auto" may be specified. If "list" is passed, a brief
table of suitable, currently plugged in PKCS#11 hardware
tokens is shown, along with their URIs. If "auto" is passed,
a suitable PKCS#11 hardware token is automatically selected
(this operation will fail if there isn't exactly one suitable
token discovered). The latter is a useful shortcut for the
most common case where a single PKCS#11 hardware token is
plugged in.
Note that many hardware security tokens implement both
PKCS#11/PIV and FIDO2 with the "hmac-secret" extension (for
example: the YubiKey 5 series), as supported with the
--fido2-device= option below. Both mechanisms are similarly
powerful, though FIDO2 is the more modern technology.
PKCS#11/PIV tokens have the benefit of being recognizable
before authentication and hence can be used for implying the
user identity to use for logging in, which FIDO2 does not
allow. PKCS#11/PIV devices generally require initialization
(i.e. storing a private/public key pair on them, see example
below) before they can be used; FIDO2 security tokens
generally do not required that, and work out of the box.
--fido2-device=PATH
Takes a path to a Linux "hidraw" device (e.g. /dev/hidraw1),
referring to a FIDO2 security token implementing the
"hmac-secret" extension that shall be able to unlock the user
account. A random salt value is generated on the host and
passed to the FIDO2 device, which calculates a HMAC hash of
the salt using an internal secret key. The result is then
used as the key to unlock the user account. The random salt
is included in the user record, so that whenever
authentication is needed it can be passed to the FIDO2 token
again.
Instead of a valid path to a FIDO2 "hidraw" device the
special strings "list" and "auto" may be specified. If "list"
is passed, a brief table of suitable discovered FIDO2 devices
is shown. If "auto" is passed, a suitable FIDO2 token is
automatically selected, if exactly one is discovered. The
latter is a useful shortcut for the most common case where a
single FIDO2 hardware token is plugged in.
Note that FIDO2 devices suitable for this option must
implement the "hmac-secret" extension. Most current devices
(such as the YubiKey 5 series) do. If the extension is not
implemented the device cannot be used for unlocking home
directories.
Note that many hardware security tokens implement both FIDO2
and PKCS#11/PIV (and thus may be used with either
--fido2-device= or --pkcs11-token-uri=), for a discussion see
above.
--fido2-with-client-pin=BOOL
When enrolling a FIDO2 security token, controls whether to
require the user to enter a PIN when unlocking the account
(the FIDO2 "clientPin" feature). Defaults to "yes". (Note:
this setting is without effect if the security token does not
support the "clientPin" feature at all, or does not allow
enabling or disabling it.)
--fido2-with-user-presence=BOOL
When enrolling a FIDO2 security token, controls whether to
require the user to verify presence (tap the token, the FIDO2
"up" feature) when unlocking the account. Defaults to "yes".
(Note: this setting is without effect if the security token
does not support the "up" feature at all, or does not allow
enabling or disabling it.)
--fido2-with-user-verification=BOOL
When enrolling a FIDO2 security token, controls whether to
require user verification when unlocking the account (the
FIDO2 "uv" feature). Defaults to "no". (Note: this setting is
without effect if the security token does not support the
"uv" feature at all, or does not allow enabling or disabling
it.)
--recovery-key=BOOL
Accepts a boolean argument. If enabled a recovery key is
configured for the account. A recovery key is a computer
generated access key that may be used to regain access to an
account if the password has been forgotten or the
authentication token lost. The key is generated and shown on
screen, and should be printed or otherwise transferred to a
secure location. A recovery key may be entered instead of a
regular password to unlock the account.
--locked=BOOLEAN
Takes a boolean argument. Specifies whether this user account
shall be locked. If true logins into this account are
prohibited, if false (the default) they are permitted (of
course, only if authorization otherwise succeeds).
--not-before=TIMESTAMP, --not-after=TIMESTAMP
These options take a timestamp string, in the format
documented in systemd.time(7) and configures points in time
before and after logins into this account are not permitted.
--rate-limit-interval=SECS, --rate-limit-burst=NUMBER
Configures a rate limit on authentication attempts for this
user. If the user attempts to authenticate more often than
the specified number, on a specific system, within the
specified time interval authentication is refused until the
time interval passes. Defaults to 10 times per 1min.
--password-hint=TEXT
Takes a password hint to store alongside the user record.
This string is stored accessible only to privileged users and
the user itself and may not be queried by other users.
Example: --password-hint="My first pet's name".
--enforce-password-policy=BOOL, -P
Takes a boolean argument. Configures whether to enforce the
system's password policy for this user, regarding quality and
strength of selected passwords. Defaults to on. -P is short
for ---enforce-password-policy=no.
--password-change-now=BOOL
Takes a boolean argument. If true the user is asked to change
their password on next login.
--password-change-min=TIME, --password-change-max=TIME,
--password-change-warn=TIME, --password-change-inactive=TIME
Each of these options takes a time span specification as
argument (in the syntax documented in systemd.time(7)) and
configures various aspects of the user's password expiration
policy. Specifically, --password-change-min= configures how
much time has to pass after changing the password of the user
until the password may be changed again. If the user tries to
change their password before this time passes the attempt is
refused. --password-change-max= configures how soon after it
has been changed the password expires and needs to be changed
again. After this time passes logging in may only proceed
after the password is changed. --password-change-warn=
specifies how much earlier than then the time configured with
--password-change-max= the user is warned at login to change
their password as it will expire soon. Finally
--password-change-inactive= configures the time which has to
pass after the password as expired until the user is not
permitted to log in or change the password anymore. Note that
these options only apply to password authentication, and do
not apply to other forms of authentication, for example
PKCS#11-based security token authentication.
--disk-size=BYTES
Either takes a size in bytes as argument (possibly using the
usual K, M, G, ... suffixes for 1024 base values), or a
percentage value and configures the disk space to assign to
the user. If a percentage value is specified (i.e. the
argument suffixed with "%") it is taken relative to the
available disk space of the backing file system. If the LUKS2
backend is used this configures the size of the loopback file
and file system contained therein. For the other storage
backends configures disk quota using the filesystem's native
quota logic, if available. If not specified, defaults to 85%
of the available disk space for the LUKS2 backend and to no
quota for the others.
--access-mode=MODE
Takes a UNIX file access mode written in octal. Configures
the access mode of the home directory itself. Note that this
is only used when the directory is first created, and the
user may change this any time afterwards. Example:
--access-mode=0700
--umask=MASK
Takes the access mode mask (in octal syntax) to apply to
newly created files and directories of the user ("umask"). If
set this controls the initial umask set for all login
sessions of the user, possibly overriding the system's
defaults.
--nice=NICE
Takes the numeric scheduling priority ("nice level") to apply
to the processes of the user at login time. Takes a numeric
value in the range -20 (highest priority) to 19 (lowest
priority).
--rlimit=LIMIT=VALUE[:VALUE]
Allows configuration of resource limits for processes of this
user, see getrlimit(2) for details. Takes a resource limit
name (e.g. "LIMIT_NOFILE") followed by an equal sign,
followed by a numeric limit. Optionally, separated by colon a
second numeric limit may be specified. If two are specified
this refers to the soft and hard limits, respectively. If
only one limit is specified the setting sets both limits in
one.
--tasks-max=TASKS
Takes a non-zero unsigned integer as argument. Configures the
maximum number of tasks (i.e. threads, where each process is
at least one thread) the user may have at any given time.
This limit applies to all tasks forked off the user's
sessions, even if they change user identity via su(1) or a
similar tool. Use --rlimit=LIMIT_NPROC= to place a limit on
the tasks actually running under the UID of the user, thus
excluding any child processes that might have changed user
identity. This controls the TasksMax= setting of the per-user
systemd slice unit user-$UID.slice. See
systemd.resource-control(5) for further details.
--memory-high=BYTES, --memory-max=BYTES
Set a limit on the memory a user may take up on a system at
any given time in bytes (the usual K, M, G, ... suffixes are
supported, to the base of 1024). This includes all memory
used by the user itself and all processes they forked off
that changed user credentials. This controls the MemoryHigh=
and MemoryMax= settings of the per-user systemd slice unit
user-$UID.slice. See systemd.resource-control(5) for further
details.
--cpu-weight=WEIGHT, --io-weight=WEIGHT
Set CPU and IO scheduling weights of the processes of the
user, including those of processes forked off by the user
that changed user credentials. Takes a numeric value in the
range 1...10000. This controls the CPUWeight= and IOWeight=
settings of the per-user systemd slice unit user-$UID.slice.
See systemd.resource-control(5) for further details.
--storage=STORAGE
Selects the storage mechanism to use for this home directory.
Takes one of "luks", "fscrypt", "directory", "subvolume",
"cifs". For details about these mechanisms, see above. If a
new home directory is created and the storage type is not
specifically specified, homed.conf(5) defines which default
storage to use.
--image-path=PATH
Takes a file system path. Configures where to place the
user's home directory. When LUKS2 storage is used refers to
the path to the loopback file, otherwise to the path to the
home directory (which may be in /home/ or any other
accessible filesystem). When unspecified defaults to
/home/$USER.home when LUKS storage is used and
/home/$USER.homedir for the other storage mechanisms. Not
defined for the "cifs" storage mechanism. To use LUKS2
storage on a regular block device (for example a USB stick)
pass the path to the block device here. Specifying the path
to a directory here when using LUKS2 storage is not allowed.
Similar, specifying the path to a regular file or device node
is not allowed if any of the other storage backends are used.
--fs-type=TYPE
When LUKS2 storage is used configures the file system type to
use inside the home directory LUKS2 container. One of
"btrfs", "ext4", "xfs". If not specified homed.conf(5)
defines which default file system type to use. Note that
"xfs" is not recommended as its support for file system
resizing is too limited.
--luks-discard=BOOL
When LUKS2 storage is used configures whether to enable the
"discard" feature of the file system. If enabled the file
system on top of the LUKS2 volume will report empty block
information to LUKS2 and the loopback file below, ensuring
that empty space in the home directory is returned to the
backing file system below the LUKS2 volume, resulting in a
"sparse" loopback file. This option mostly defaults to off,
since this permits over-committing home directories which
results in I/O errors if the underlying file system runs full
while the upper file system wants to allocate a block. Such
I/O errors are generally not handled well by file systems nor
applications. When LUKS2 storage is used on top of regular
block devices (instead of on top a loopback file) the discard
logic defaults to on.
--luks-offline-discard=BOOL
Similar to --luks-discard=, controls the trimming of the file
system. However, while --luks-discard= controls what happens
when the home directory is active, --luks-offline-discard=
controls what happens when it becomes inactive, i.e. whether
to trim/allocate the storage when deactivating the home
directory. This option defaults to on, to ensure disk space
is minimized while a user is not logged in.
--luks-cipher=CIPHER, --luks-cipher-mode=MODE,
--luks-volume-key-size=BITS, --luks-pbkdf-type=TYPE,
--luks-pbkdf-hash-algorithm=ALGORITHM,
--luks-pbkdf-time-cost=SECONDS, --luks-pbkdf-memory-cost=BYTES,
--luks-pbkdf-parallel-threads=THREADS
Configures various cryptographic parameters for the LUKS2
storage mechanism. See cryptsetup(8) for details on the
specific attributes.
--nosuid=BOOL, --nodev=BOOL, --noexec=BOOL
Configures the "nosuid", "nodev" and "noexec" mount options
for the home directories. By default "nodev" and "nosuid" are
on, while "noexec" is off. For details about these mount
options see mount(8).
--cifs-domain=DOMAIN, --cifs-user-name=USER,
--cifs-service=SERVICE
Configures the Windows File Sharing (CIFS) domain and user to
associate with the home directory/user account, as well as
the file share ("service") to mount as directory. The latter
is used when "cifs" storage is selected.
--stop-delay=SECS
Configures the time the per-user service manager shall
continue to run after the all sessions of the user ended. The
default is configured in logind.conf(5) (for home directories
of LUKS2 storage located on removable media this defaults to
0 though). A longer time makes sure quick, repetitive logins
are more efficient as the user's service manager doesn't have
to be started every time.
--kill-processes=BOOL
Configures whether to kill all processes of the user on
logout. The default is configured in logind.conf(5).
--auto-login=BOOL
Takes a boolean argument. Configures whether the graphical UI
of the system should automatically log this user in if
possible. Defaults to off. If less or more than one user is
marked this way automatic login is disabled.
