|
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. |
|
|
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | USER RECORD PROPERTIES | COMMANDS | CREDENTIALS | KERNEL COMMAND LINE | EXIT STATUS | ENVIRONMENT | EXAMPLES | SEE ALSO | NOTES | COLOPHON |
|
|
|
HOMECTL(1) homectl HOMECTL(1)
homectl, systemd-homed-firstboot.service - Create, remove, change
or inspect home directories
homectl [OPTIONS...] {COMMAND} [NAME...]
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.
The following general options are understood (further options
that control the various properties of user records managed by
systemd-homed.service are documented further down):
--identity=FILE
Read the user's JSON record from the specified file. If
passed as "-" read the user record from standard input. The
supplied JSON object must follow the structure documented in
JSON User Records[1]. This option may be used in conjunction
with the create and update commands (see below), where it
allows configuring the user record in JSON as-is, instead of
setting the individual user record properties (see below).
Added in version 245.
--json=FORMAT, -j
Controls whether to output the user record in JSON format, if
the inspect command (see below) is used. Takes one of
"pretty", "short" or "off". If "pretty" human-friendly
whitespace and newlines are inserted in the output to make
the JSON data more readable. If "short" all superfluous
whitespace is suppressed. If "off" (the default) the user
information is not shown in JSON format but in a friendly
human readable formatting instead. The -j option picks
"pretty" when run interactively and "short" otherwise.
Added in version 245.
--export-format=FORMAT, -E, -EE
When used with the inspect verb in JSON mode (see above) may
be used to suppress certain aspects of the JSON user record
on output. Specifically, if "stripped" format is used the
binding and runtime fields of the record are removed. If
"minimal" format is used the cryptographic signature is
removed too. If "full" format is used the full JSON record is
shown (this is the default). This option is useful for
copying an existing user record to a different system in
order to create a similar user there with the same settings.
Specifically: homectl inspect -EE | ssh root@othersystem
homectl create -i- may be used as simple command line for
replicating a user on another host. -E is equivalent to -j
--export-format=stripped, -EE to -j --export-format=minimal.
Note that when replicating user accounts user records
acquired in "stripped" mode will retain the original
cryptographic signatures and thus may only be modified when
the private key to update them is available on the
destination machine. When replicating users in "minimal"
mode, the signature is removed during the replication and
thus the record will be implicitly signed with the key of the
destination machine and may be updated there without any
private key replication.
Added in version 245.
--offline
Do not attempt to update the copy of the user record and blob
directory that is embedded inside of the home area. This
allows for operation on home areas that are absent, or
without needing to authenticate as the user being modified.
Added in version 256.
-H, --host=
Execute the operation remotely. Specify a hostname, or a
username and hostname separated by "@", to connect to. The
hostname may optionally be suffixed by a port ssh is
listening on, separated by ":", and then a container name,
separated by "/", which connects directly to a specific
container on the specified host. This will use SSH to talk to
the remote machine manager instance. Container names may be
enumerated with machinectl -H HOST. Put IPv6 addresses in
brackets.
-M, --machine=
Execute operation on a local container. Specify a container
name to connect to, optionally prefixed by a user name to
connect as and a separating "@" character. If the special
string ".host" is used in place of the container name, a
connection to the local system is made (which is useful to
connect to a specific user's user bus: "--user
[email protected]"). If the "@" syntax is not used, the
connection is made as root user. If the "@" syntax is used
either the left hand side or the right hand side may be
omitted (but not both) in which case the local user name and
".host" are implied.
--no-pager
Do not pipe output into a pager.
--no-legend
Do not print the legend, i.e. column headers and the footer
with hints.
--no-ask-password
Do not query the user for authentication for privileged
operations.
-h, --help
Print a short help text and exit.
--version
Print a short version string and exit.
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 $XDG_SESSION_TYPE). This is read by the display
manage to pick the default session type the user is logged
into.
Added in version 256.
The following commands are understood:
list
List all home directories (along with brief details)
currently managed by systemd-homed.service. This command is
also executed if none is specified on the command line. (Note
that the list of users shown by this command does not include
users managed by other subsystems, such as system users or
any traditional users listed in /etc/passwd.)
Added in version 245.
activate USER [USER...]
Activate one or more home directories. The home directories
of each listed user will be activated and made available
under their mount points (typically in /home/$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.
When invoked with the firstboot command, homectl supports the
service credentials logic as implemented by
ImportCredential=/LoadCredential=/SetCredential= (see
systemd.exec(5) for details). The following credentials are used
when passed in:
home.create.*
If one or more credentials whose names begin with
"home.create.", followed by a valid UNIX username are passed,
a new home area is created, one for each specified user
record.
Added in version 256.
systemd.firstboot=
This boolean will disable the effect of homectl firstboot
command. It's primarily interpreted by systemd-firstboot(1).
Added in version 256.
On success, 0 is returned, a non-zero failure code otherwise.
When a command is invoked with with, the exit status of the child
is propagated. Effectively, homectl will exit without error if
the command is successfully invoked and finishes successfully.
$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.
Example 1. Create a user "waldo" in the administrator group
"wheel", and assign 500 MiB disk space to them.
homectl create waldo --real-name="Waldo McWaldo" -G wheel --disk-size=500M
Example 2. Create a user "wally" on a USB stick, and assign a
maximum of 500 concurrent tasks to them.
homectl create wally --real-name="Wally McWally" --image-path=/dev/disk/by-id/usb-SanDisk_Ultra_Fit_476fff954b2b5c44-0:0 --tasks-max=500
Example 3. Change nice level of user "odlaw" to +5 and make sure
the environment variable $SOME is set to the string "THING" for
them on login.
homectl update odlaw --nice=5 --setenv=SOME=THING
Example 4. Set up authentication with a YubiKey security token
using PKCS#11/PIV:
# Clear the Yubikey from any old keys (careful!)
ykman piv reset
# Generate a new private/public key pair on the device, store the public key in 'pubkey.pem'.
ykman piv generate-key -a RSA2048 9d pubkey.pem
# Create a self-signed certificate from this public key, and store it on the device.
ykman piv generate-certificate --subject "Knobelei" 9d pubkey.pem
# We don't need the public key on disk anymore
rm pubkey.pem
# Allow the security token to unlock the account of user 'lafcadio'.
homectl update lafcadio --pkcs11-token-uri=auto
Example 5. Set up authentication with a FIDO2 security token:
# Allow a FIDO2 security token to unlock the account of user 'nihilbaxter'.
homectl update nihilbaxter --fido2-device=auto
systemd(1), systemd-homed.service(8), homed.conf(5),
userdbctl(1), useradd(8), cryptsetup(8)
1. JSON User Records
https://systemd.io/USER_RECORD
2. Icon Naming Specification
https://standards.freedesktop.org/icon-naming-spec/icon-naming-spec-latest.html
3. User Record Blob Directories
https://systemd.io/USER_RECORD_BLOB_DIRS
4. 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 HOMECTL(1)
Pages that refer to this page: homed.conf(5), org.freedesktop.home1(5), kernel-command-line(7), systemd.directives(7), systemd.index(7), systemd.system-credentials(7), pam_systemd_home(8), systemd-homed.service(8)
|
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. |
|