DESCRIPTION¶
homectl may be used to create, remove, change or inspect a
user's home directory. It's primarily a command interfacing with
systemd-homed.service(8) which manages home directories of users.
Home directories managed by systemd-homed.service are
self-contained, and thus include the user's full metadata record in the
home's data storage itself, making them easy to migrate between machines. In
particular, a home directory describes a matching user record, and every
user record managed by systemd-homed.service also implies existence and
encapsulation of a home directory. The user account and home directory
become the same concept.
The following backing storage mechanisms are supported:
•An individual LUKS2 encrypted loopback file for a
user, stored in /home/*.home. At login the file system contained in this files
is mounted, after the LUKS2 encrypted volume has been attached. The user's
password is identical to the encryption passphrase of the LUKS2 volume. Access
to data without preceding user authentication is thus not possible, even for
the system administrator. This storage mechanism provides the strongest data
security and is thus recommended.
•Similar, but the LUKS2 encrypted file system is
located on regular block device, such as a USB storage stick. In this mode
home directories and all data they include are nicely migratable between
machines, simply by plugging the USB stick into different systems at different
times.
•An encrypted directory using "fscrypt"
on file systems that support it (at the moment this is primarily
"ext4"), located in /home/*.homedir. This mechanism also provides
encryption, but substantially weaker than LUKS2, as most file system metadata
is unprotected. Moreover it currently does not support changing user passwords
once the home directory has been created.
•A "btrfs" subvolume for each user, also
located in /home/*.homedir. This provides no encryption, but good quota
support.
•A regular directory for each user, also located
in /home/*.homedir. This provides no encryption, but is a suitable fallback
available on all machines, even where LUKS2, "fscrypt" or
"btrfs" support is not available.
•An individual Windows file share (CIFS) for each
user.
Note that systemd-homed.service and homectl will not manage
"classic" UNIX user accounts as created with useradd(8) or
similar tools. In particular, this functionality is not suitable for
managing system users (i.e. users with a UID below 1000) but is exclusive to
regular ("human") users.
Note that users/home directories managed via
systemd-homed.service do not show up in /etc/passwd and similar
files, they are synthesized via glibc NSS during runtime. They are thus
resolvable and may be enumerated via the getent(1) tool.
This tool interfaces directly with systemd-homed.service, and may
execute specific commands on the home directories it manages. Since every
home directory managed that way also defines a JSON user and group record
these home directories may also be inspected and enumerated via
userdbctl(1).
Home directories managed by systemd-homed.service are usually in
one of two states, or in a transition state between them: when
"active" they are unlocked and mounted, and thus accessible to the
system and its programs; when "inactive" they are not mounted and
thus not accessible. Activation happens automatically at login of the user
and usually can only complete after a password (or other authentication
token) has been supplied. Deactivation happens after the user fully logged
out. A home directory remains active as long as the user is logged in at
least once, i.e. has at least one login session. When the user logs in a
second time simultaneously the home directory remains active. It is
deactivated only after the last of the user's sessions ends.
USER RECORD PROPERTIES¶
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.
Added in version 245.
--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.
Added in version 245.
--email-address=EMAIL
Takes an electronic mail address to associate with the
user. On log-in the
$EMAIL environment variable is initialized from
this value.
Added in version 245.
--location=TEXT
Takes location specification for this user. This is
free-form text, which might or might not be usable by geo-location
applications. Example:
--location="Berlin, Germany" or
--location="Basement, Room 3a"
Added in version 245.
--icon-name=ICON
Takes an icon name to associate with the user, following
the scheme defined by the
Icon Naming Specification[2].
Added in version 245.
--home-dir=PATH,
-dPATH
Takes a path to use as home directory for the user. Note
that this is the directory the user's home directory is mounted to while the
user is logged in. This is not where the user's data is actually stored, see
--image-path= for that. If not specified defaults to /home/$USER.
Added in version 245.
--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 changing this option for existing home directories
generally has no effect on home directories that already have been
registered locally (have a local binding), as the UID used for an
account on the local system is determined when the home directory is first
activated on it, and then remains in effect until the home directory is
removed.
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.
Added in version 245.
--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.
Added in version 245.
--capability-bounding-set=CAPABILITIES,
--capability-ambient-set=CAPABILITIES
These options take a space separated list of process
capabilities (e.g.
CAP_WAKE_ALARM,
CAP_BLOCK_SUSPEND, ...) that
shall be set in the capability bounding and ambient sets for all the user's
sessions. See
capabilities(7) for details on the capabilities concept.
These options may be used more than once, in which case the specified lists
are combined. If the parameter begins with a "~" character the
effect is inverted: the specified capability is dropped from the specific set.
Added in version 254.
--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/.
Added in version 245.
--shell=SHELL
Takes a file system path. Specifies the shell binary to
execute on terminal logins. If not specified defaults to /bin/bash.
Added in version 245.
--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=.
Added in version 245.
--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).)
Added in version 245.
--language=LANG
Takes a comma- or colon-separated list of languages
preferred by the user, ordered by descending priority. The
$LANG and
$LANGUAGE environment variables are initialized from this value on
login, and thus values suitible for these environment variables are accepted
here, for example
--language=de_DE.UTF-8. This option may be used more
than once, in which case the language lists are concatenated.
Added in version 245.
--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.
Added in version 245.
--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.
Added in version 245.
--fido2-credential-algorithm=STRING
Specify COSE algorithm used in credential generation. The
default value is "es256". Supported values are "es256",
"rs256" and "eddsa".
"es256" denotes ECDSA over NIST P-256 with SHA-256.
"rs256" denotes 2048-bit RSA with PKCS#1.5 padding and SHA-256.
"eddsa" denotes EDDSA over Curve25519 with SHA-512.
Note that your authenticator may choose not to support some
algorithms.
Added in version 251.
--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.
The FIDO2 device may be subsequently removed by setting the device
path to an empty string (e.g. homectl update $USER
--fido2-device="").
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.
Added in version 246.
--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.)
Added in version 249.
--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.)
Added in version 249.
--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.)
Added in version 249.
--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.
Added in version 247.
--blob=PATH, -b PATH,
--blob=FILENAME=PATH, -b
FILENAME=PATH
Accepts either a directory path, or a file name followed
by a file path. If just a directory path is specified, then the user's entire
blob directory is replaced the specified path. Note that this replacement is
performed before per-file manipulations are applied, which means these
per-file manipulations will be applied on top of the specified directory. If a
filename and file path are specified, then the single specified blob file will
be overwritten with the specified path. If completely blank, the entire blob
directory is emptied out (which also resets all previous blob-related flags up
to this point). If a filename is specified but the corresponding path is
blank, that single file will be deleted from the blob directory. All changes
are performed in temporary copies of the specified files in directories, which
means that the originals specified on the command line are not modified. See
User Record Blob Directories[3] for more information about blob
directories.
Added in version 256.
--avatar=PATH,
--login-background=PATH
Accept a file path. If set, the specified file is used to
overwrite the corresponding file in the user's blob directory. If blank, the
corresponding file is deleted from the blob directory. Essentially, these
options are shortcuts to
--blob=FILENAME=PATH for the known
filenames defined in
User Record Blob Directories[3].
Added in version 256.
--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).
Added in version 245.
--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.
Added in version 245.
--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.
Added in version 245.
--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".
Added in version 245.
--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.
Added in version 245.
--password-change-now=BOOL
Takes a boolean argument. If true the user is asked to
change their password on next login.
Added in version 245.
--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.
Added in version 245.
--disk-size=BYTES
Either takes a size in bytes as argument (possibly using
the usual K, M, G, ... suffixes for 1024 base values), a percentage value, or
the special strings "min" or "max", 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 specified as "min" assigns
the minimal disk space permitted by the constraints of the backing file system
and other limits, when specified as "max" assigns the maximum disk
space available. 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.
Added in version 245.
--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
Added in version 245.
--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.
Added in version 245.
--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).
Added in version 245.
--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.
Added in version 245.
--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.
Added in version 245.
--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-$UID.slice. See
systemd.resource-control(5) for further
details.
Added in version 245.
--cpu-weight=WEIGHT,
--io-weight=WEIGHT
Set CPU and IO scheduling weights of the processes of the
user, including those of processes forked off by the user that changed user
credentials. Takes a numeric value in the range 1...10000. This controls the
CPUWeight= and
IOWeight= settings of the per-user systemd slice
unit user-$UID.slice. See
systemd.resource-control(5) for further
details.
Added in version 245.
--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.
Added in version 245.
--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.
Added in version 245.
--drop-caches=BOOL
Automatically flush OS file system caches on logout. This
is useful in combination with the fscrypt storage backend to ensure the OS
does not keep decrypted versions of the files and directories in memory (and
accessible) after logout. This option is also supported on other backends, but
should not bring any benefit there. Defaults to off, except if the selected
storage backend is fscrypt, where it defaults to on. Note that flushing OS
caches will negatively influence performance of the OS shortly after logout.
Added in version 250.
--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.
Added in version 245.
--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.
Added in version 245.
--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.
Added in version 246.
--luks-extra-mount-options=OPTIONS
Takes a string containing additional mount options to use
when mounting the LUKS volume. If specified, this string will be appended to
the default, built-in mount options.
Added in version 250.
--luks-cipher=CIPHER,
--luks-cipher-mode=MODE,
--luks-volume-key-size=BYTES,
--luks-pbkdf-type=TYPE,
--luks-pbkdf-hash-algorithm=ALGORITHM,
--luks-pbkdf-force-iterations=ITERATIONS,
--luks-pbkdf-time-cost=SECONDS,
--luks-pbkdf-memory-cost=BYTES,
--luks-pbkdf-parallel-threads=THREADS,
--luks-sector-size=BYTES
Configures various cryptographic parameters for the LUKS2
storage mechanism. See
cryptsetup(8) for details on the specific
attributes.
Note that homectl uses bytes for key size, like
/proc/crypto, but cryptsetup(8) uses bits.
Added in version 245.
--auto-resize-mode=
Configures whether to automatically grow and/or shrink
the backing file system on login and logout. Takes one of the strings
"off", "grow", "shrink-and-grow". Only applies
to the LUKS2 backend currently, and if the btrfs file system is used inside it
(since only then online growing/shrinking of the file system is supported).
Defaults to "shrink-and-grow", if LUKS2/btrfs is used, otherwise is
off. If set to "off" no automatic shrinking/growing during login or
logout is done. If set to "grow" the home area is grown to the size
configured via
--disk-size= should it currently be smaller. If it
already matches the configured size or is larger no operation is executed. If
set to "shrink-and-grow" the home area is also resized during logout
to the minimal size the used disk space and file system constraints permit.
This mode thus ensures that while a home area is activated it is sized to the
configured size, but while deactivated it is compacted taking up only the
minimal space possible. Note that if the system is powered off abnormally or
if the user otherwise not logged out cleanly the shrinking operation will not
take place, and the user has to re-login/logout again before it is executed
again.
Added in version 250.
--rebalance-weight=
Configures the weight parameter for the free disk space
rebalancing logic. Only applies to the LUKS2 backend (since for the LUKS2
backend disk space is allocated from a per-user loopback file system instead
of immediately from a common pool like the other backends do it). In regular
intervals free disk space in the active home areas and their backing storage
is redistributed among them, taking the weight value configured here into
account. Expects an integer in the range 1...10000, or the special string
"off". If not specified defaults to 100. The weight is used to scale
free space made available to the home areas: a home area with a weight of 200
will get twice the free space as one with a weight of 100; a home area with a
weight of 50 will get half of that. The backing file system will be assigned
space for a weight of 20. If set to "off" no automatic free space
distribution is done for this home area. Note that resizing the home area
explicitly (with
homectl resize see below) will implicitly turn off the
automatic rebalancing. To reenable the automatic rebalancing use
--rebalance-weight= with an empty parameter.
Added in version 250.
--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).
Added in version 245.
--cifs-domain=DOMAIN,
--cifs-user-name=USER,
--cifs-service=SERVICE,
--cifs-extra-mount-options=OPTIONS
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. The file share should be specified in
format "//
host/
share/
directory/...". The
directory part is optional — if not specified the home directory will
be placed in the top-level directory of the share. The
--cifs-extra-mount-options= setting allows specifying additional mount
options when mounting the share, see
mount.cifs(8) for details.
Added in version 245.
--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.
Added in version 245.
--kill-processes=BOOL
Configures whether to kill all processes of the user on
logout. The default is configured in
logind.conf(5).
Added in version 245.
--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.
Added in version 245.
--session-launcher=LAUNCHER
Takes a string argument. Configures the user's preferred
session launcher .desktop entry file (i.e. "gnome",
"plasma", or other names that appear in /usr/share/xesssions/ or
/usr/share/wayland-sessions). This is read by the display manager to pick the
default session that is launched when the user logs in.
Added in version 256.
--session-type=TYPE
Takes a string argument. Configures the user's preferred
session type (i.e. "x11", "wayland", and other values
accepted by
$XDG_SESSION_TYPE). This is read by the display manage to
pick the default session type the user is logged into.
Added in version 256.
COMMANDS¶
The following commands are understood:
list
List all home directories (along with brief details)
currently managed by systemd-homed.service. This command is also executed if
none is specified on the command line. (Note that the list of users shown by
this command does not include users managed by other subsystems, such as
system users or any traditional users listed in /etc/passwd.)
Added in version 245.
activate USER [USER...]
Activate one or more home directories. The home
directories of each listed user will be activated and made available under
their mount points (typically in /home/$USER). Note that any home activated
this way stays active indefinitely, until it is explicitly deactivated again
(with
deactivate, see below), or the user logs in and out again and it
thus is deactivated due to the automatic deactivation-on-logout logic.
Activation of a home directory involves various operations that
depend on the selected storage mechanism. If the LUKS2 mechanism is used,
this generally involves: inquiring the user for a password, setting up a
loopback device, validating and activating the LUKS2 volume, checking the
file system, mounting the file system, and potentially changing the
ownership of all included files to the correct UID/GID.
Added in version 245.
deactivate USER [USER...]
Deactivate one or more home directories. This undoes the
effect of
activate.
Added in version 245.
inspect USER [USER...]
Show various details about the specified home
directories. This shows various information about the home directory and its
user account, including runtime data such as current state, disk use and
similar. Combine with
--json= to show the detailed JSON user record
instead, possibly combined with
--export-format= to suppress certain
aspects of the output.
Added in version 245.
authenticate USER [USER...]
Validate authentication credentials of a home directory.
This queries the caller for a password (or similar) and checks that it
correctly unlocks the home directory. This leaves the home directory in the
state it is in, i.e. it leaves the home directory in inactive state if it was
inactive before, and in active state if it was active before.
Added in version 245.
create USER, create
--identity=PATH [USER]
Create a new home directory/user account of the specified
name. Use the various user record property options (as documented above) to
control various aspects of the home directory and its user accounts.
The specified user name should follow the strict syntax described
on User/Group Name Syntax[4].
Added in version 245.
remove USER
Remove a home directory/user account. This will remove
both the home directory's user record and the home directory itself, and thus
delete all files and directories owned by the user.
Added in version 245.
update USER, update
--identity=PATH [USER]
Update a home directory/user account. Use the various
user record property options (as documented above) to make changes to the
account, or alternatively provide a full, updated JSON user record via the
--identity= option.
Note that changes to user records not signed by a cryptographic
private key available locally are not permitted, unless --identity=
is used with a user record that is already correctly signed by a recognized
private key.
Added in version 245.
passwd USER
Change the password of the specified home directory/user
account.
Added in version 245.
resize USER BYTES
Change the disk space assigned to the specified home
directory. If the LUKS2 storage mechanism is used this will automatically
resize the loopback file and the file system contained within. Note that if
"ext4" is used inside of the LUKS2 volume, it is necessary to
deactivate the home directory before shrinking it (i.e the user has to log
out). Growing can be done while the home directory is active. If
"xfs" is used inside of the LUKS2 volume the home directory may not
be shrunk whatsoever. On all three of "ext4", "xfs" and
"btrfs" the home directory may be grown while the user is logged in,
and on the latter also shrunk while the user is logged in. If the
"subvolume", "directory", "fscrypt" storage
mechanisms are used, resizing will change file system quota. The size
parameter may make use of the usual suffixes B, K, M, G, T (to the base of
1024). The special strings "min" and "max" may be
specified in place of a numeric size value, for minimizing or maximizing disk
space assigned to the home area, taking constraints of the file system, disk
usage inside the home area and on the backing storage into account.
Added in version 245.
lock USER
Temporarily suspend access to the user's home directory
and remove any associated cryptographic keys from memory. Any attempts to
access the user's home directory will stall until the home directory is
unlocked again (i.e. re-authenticated). This functionality is primarily
intended to be used during system suspend to make sure the user's data cannot
be accessed until the user re-authenticates on resume. This operation is only
defined for home directories that use the LUKS2 storage mechanism.
Added in version 245.
unlock USER
Resume access to the user's home directory again, undoing
the effect of
lock above. This requires authentication of the user, as
the cryptographic keys required for access to the home directory need to be
reacquired.
Added in version 245.
lock-all
Execute the
lock command on all suitable home
directories at once. This operation is generally executed on system suspend
(i.e. by
systemctl suspend and related commands), to ensure all active
user's cryptographic keys for accessing their home directories are removed
from memory.
Added in version 245.
deactivate-all
Execute the
deactivate command on all active home
directories at once. This operation is generally executed on system shut down
(i.e. by
systemctl poweroff and related commands), to ensure all active
user's home directories are fully deactivated before /home/ and related file
systems are unmounted.
Added in version 247.
with USER COMMAND...
Activate the specified user's home directory, run the
specified command (under the caller's identity, not the specified user's) and
deactivate the home directory afterwards again (unless the user is logged in
otherwise). This command is useful for running privileged backup scripts and
such, but requires authentication with the user's credentials in order to be
able to unlock the user's home directory.
Added in version 245.
rebalance
Rebalance free disk space between active home areas and
the backing storage. See
--rebalance-weight= above. This executes no
operation unless there's at least one active LUKS2 home area that has disk
space rebalancing enabled. This operation is synchronous: it will only
complete once disk space is rebalanced according to the rebalancing weights.
Note that rebalancing also takes place automatically in the background in
regular intervals. Use this command to synchronously ensure disk space is
properly redistributed before initiating an operation requiring large amounts
of disk space.
Added in version 250.
firstboot
This command is supposed to be invoked during the initial
boot of the system. It checks whether any regular home area exists so far, and
if not queries the user interactively on the console for user name and
password and creates one. Alternatively, if one or more service credentials
whose name starts with "home.create." are passed to the command
(containing a user record in JSON format) these users are automatically
created at boot.
This command is invoked by the systemd-homed-firstboot.service
service unit.
Added in version 256.
ENVIRONMENT¶
$SYSTEMD_LOG_LEVEL
The maximum log level of emitted messages (messages with
a higher log level, i.e. less important ones, will be suppressed). Takes a
comma-separated list of values. A value may be either one of (in order of
decreasing importance)
emerg,
alert,
crit,
err,
warning,
notice,
info,
debug, or an integer in the
range 0...7. See
syslog(3) for more information. Each value may
optionally be prefixed with one of
console,
syslog,
kmsg
or
journal followed by a colon to set the maximum log level for that
specific log target (e.g.
SYSTEMD_LOG_LEVEL=debug,console:info
specifies to log at debug level except when logging to the console which
should be at info level). Note that the global maximum log level takes
priority over any per target maximum log levels.
$SYSTEMD_LOG_COLOR
A boolean. If true, messages written to the tty will be
colored according to priority.
This setting is only useful when messages are written directly to
the terminal, because journalctl(1) and other tools that display logs
will color messages based on the log level on their own.
$SYSTEMD_LOG_TIME
A boolean. If true, console log messages will be prefixed
with a timestamp.
This setting is only useful when messages are written directly to
the terminal or a file, because journalctl(1) and other tools that
display logs will attach timestamps based on the entry metadata on their
own.
$SYSTEMD_LOG_LOCATION
A boolean. If true, messages will be prefixed with a
filename and line number in the source code where the message originates.
Note that the log location is often attached as metadata to
journal entries anyway. Including it directly in the message text can
nevertheless be convenient when debugging programs.
$SYSTEMD_LOG_TID
A boolean. If true, messages will be prefixed with the
current numerical thread ID (TID).
Note that the this information is attached as metadata to journal
entries anyway. Including it directly in the message text can nevertheless
be convenient when debugging programs.
$SYSTEMD_LOG_TARGET
The destination for log messages. One of
console
(log to the attached tty),
console-prefixed (log to the attached tty
but with prefixes encoding the log level and "facility", see
syslog(3),
kmsg (log to the kernel circular log buffer),
journal (log to the journal),
journal-or-kmsg (log to the
journal if available, and to kmsg otherwise),
auto (determine the
appropriate log target automatically, the default),
null (disable log
output).
$SYSTEMD_LOG_RATELIMIT_KMSG
Whether to ratelimit kmsg or not. Takes a boolean.
Defaults to "true". If disabled, systemd will not ratelimit messages
written to kmsg.
$SYSTEMD_PAGER
Pager to use when
--no-pager is not given;
overrides
$PAGER. If neither
$SYSTEMD_PAGER nor
$PAGER
are set, a set of well-known pager implementations are tried in turn,
including
less(1) and
more(1), until one is found. If no pager
implementation is discovered no pager is invoked. Setting this environment
variable to an empty string or the value "cat" is equivalent to
passing
--no-pager.
Note: if $SYSTEMD_PAGERSECURE is not set,
$SYSTEMD_PAGER (as well as $PAGER) will be silently
ignored.
$SYSTEMD_LESS
Override the options passed to
less (by default
"FRSXMK").
Users might want to change two options in particular:
K
This option instructs the pager to exit immediately when
Ctrl+C is pressed. To allow
less to handle Ctrl+C itself to switch back
to the pager command prompt, unset this option.
If the value of $SYSTEMD_LESS does not include
"K", and the pager that is invoked is less, Ctrl+C will be
ignored by the executable, and needs to be handled by the pager.
X
This option instructs the pager to not send termcap
initialization and deinitialization strings to the terminal. It is set by
default to allow command output to remain visible in the terminal even after
the pager exits. Nevertheless, this prevents some pager functionality from
working, in particular paged output cannot be scrolled with the mouse.
Note that setting the regular $LESS environment variable
has no effect for less invocations by systemd tools.
See less(1) for more discussion.
$SYSTEMD_LESSCHARSET
Override the charset passed to
less (by default
"utf-8", if the invoking terminal is determined to be UTF-8
compatible).
Note that setting the regular $LESSCHARSET environment
variable has no effect for less invocations by systemd tools.
$SYSTEMD_PAGERSECURE
Takes a boolean argument. When true, the
"secure" mode of the pager is enabled; if false, disabled. If
$SYSTEMD_PAGERSECURE is not set at all, secure mode is enabled if the
effective UID is not the same as the owner of the login session, see
geteuid(2) and
sd_pid_get_owner_uid(3). In secure mode,
LESSSECURE=1 will be set when invoking the pager, and the pager shall
disable commands that open or create new files or start new subprocesses. When
$SYSTEMD_PAGERSECURE is not set at all, pagers which are not known to
implement secure mode will not be used. (Currently only
less(1)
implements secure mode.)
Note: when commands are invoked with elevated privileges, for
example under sudo(8) or pkexec(1), care must be taken to
ensure that unintended interactive features are not enabled.
"Secure" mode for the pager may be enabled automatically as
describe above. Setting SYSTEMD_PAGERSECURE=0 or not removing it from
the inherited environment allows the user to invoke arbitrary commands. Note
that if the $SYSTEMD_PAGER or $PAGER variables are to be
honoured, $SYSTEMD_PAGERSECURE must be set too. It might be
reasonable to completely disable the pager using --no-pager
instead.
$SYSTEMD_COLORS
Takes a boolean argument. When true, systemd and
related utilities will use colors in their output, otherwise the output will
be monochrome. Additionally, the variable can take one of the following
special values: "16", "256" to restrict the use of colors
to the base 16 or 256 ANSI colors, respectively. This can be specified to
override the automatic decision based on $TERM and what the console is
connected to.
$SYSTEMD_URLIFY
The value must be a boolean. Controls whether clickable
links should be generated in the output for terminal emulators supporting
this. This can be specified to override the decision that systemd makes
based on $TERM and other conditions.