machinectl — Control the systemd machine manager
machinectl [OPTIONS...] {COMMAND} [NAME...]
machinectl may be used to introspect and control the state of the systemd(1) virtual machine and container registration manager systemd-machined.service(8).
machinectl may be used to execute operations on machines and images. Machines in this sense are considered running instances of:
Virtual Machines (VMs) that virtualize hardware to run full operating system (OS) instances (including their kernels) in a virtualized environment on top of the host OS.
Containers that share the hardware and OS kernel with the host OS, in order to run OS userspace instances on top the host OS.
The host system itself.
Machines are identified by names that follow the same rules as UNIX and DNS hostnames. For details, see below.
Machines are instantiated from disk or file system images that frequently — but not necessarily — carry the same name as machines running from them. Images in this sense may be:
Directory trees containing an OS, including the
top-level directories /usr/,
/etc/, and so on.
btrfs subvolumes containing OS trees, similar to regular directory trees.
Binary "raw" disk image files containing MBR or GPT partition tables and Linux file systems.
Similarly, block devices containing MBR or GPT partition tables and file systems.
The file system tree of the host OS itself.
The following commands are understood:
List currently running (online) virtual
machines and containers. To enumerate machine images that can
be started, use list-images (see
below). Note that this command hides the special
".host" machine by default. Use the
--all switch to show it.
NAME…¶Show runtime status information about one or more virtual machines and containers, followed by the most recent log data from the journal. This function is intended to generate human-readable output. If you are looking for computer-parsable output, use show instead. Note that the log data shown is reported by the virtual machine or container manager, and frequently contains console output of the machine, but not necessarily journal contents of the machine itself.
NAME…]¶Show properties of one or more registered virtual machines or containers or the manager
itself. If no argument is specified, properties of the manager will be shown. If a NAME is specified,
properties of this virtual machine or container are shown. By default, empty properties are suppressed. Use
--all to show those too. To select specific properties to show, use
--property=. This command is intended to be used whenever computer-parsable output is
required, and does not print the control group tree or journal entries. Use status if you
are looking for formatted human-readable output.
NAME…¶Start a container as a system service, using
systemd-nspawn(1).
This starts systemd-nspawn@.service,
instantiated for the specified machine name, similar to the
effect of systemctl start on the service
name. systemd-nspawn looks for a container
image by the specified name in
/var/lib/machines/ (and other search
paths, see below) and runs it. Use
list-images (see below) for listing
available container images to start.
Note that systemd-machined.service(8) also interfaces with a variety of other container and VM managers, systemd-nspawn is just one implementation of it. Most of the commands available in machinectl may be used on containers or VMs controlled by other managers, not just systemd-nspawn. Starting VMs and container images on those managers requires manager-specific tools.
To interactively start a container on the command line with full access to the container's console, please invoke systemd-nspawn directly. To stop a running container use machinectl poweroff.
NAME]¶Open an interactive terminal login session in
a container or on the local host. If an argument is supplied,
it refers to the container machine to connect to. If none is
specified, or the container name is specified as the empty
string, or the special machine name ".host"
(see below) is specified, the connection is made to the local
host instead. This will create a TTY connection to a specific
container or the local host and asks for the execution of a
getty on it. Note that this is only supported for containers
running
systemd(1)
as init system.
This command will open a full login prompt on the
container or the local host, which then asks for username and
password. Use shell (see below) or
systemd-run(1)
with the --machine= switch to directly invoke
a single command, either interactively or in the
background.
NAME@]NAME [PATH [ARGUMENTS…]]] ¶Open an interactive shell session in a
container or on the local host. The first argument refers to
the container machine to connect to. If none is specified, or
the machine name is specified as the empty string, or the
special machine name ".host" (see below) is
specified, the connection is made to the local host
instead. This works similarly to login, but
immediately invokes a user process. This command runs the
specified executable with the specified arguments, or the
default shell for the user if none is specified, or
/bin/sh if no default shell is found. By default,
--uid=, or by prefixing the machine name with
a username and an "@" character, a different
user may be selected. Use --setenv= to set
environment variables for the executed process.
Note that machinectl shell does not propagate the exit code/status of the invoked shell process. Use systemd-run instead if that information is required (see below).
Using the shell command without arguments (thus invoking the executed shell or command on the local host), is in many ways similar to a su(1) session, but, unlike su, completely isolates the new session from the originating session, so that it shares no process or session properties and is in a clean well-defined state. It will be tracked in a new utmp, login, audit, security, and keyring sessions, and will not inherit any environment variables or resource limits, among other properties.
Note that
systemd-run(1) with
its --machine= switch may be used in place of the machinectl
shell command, and allows non-interactive operation, more detailed and low-level
configuration of the invoked unit, as well as access to runtime and exit code/status information of
the invoked shell process. In particular, use systemd-run's
--wait switch to propagate exit status information of the invoked process. Use
systemd-run's --pty switch to acquire an interactive shell,
similarly to machinectl shell. In general, systemd-run is
preferable for scripting purposes. However, note that systemd-run might require
higher privileges than machinectl shell.
NAME…, disable NAME…¶Enable or disable a container as a system service to start at system boot, using
systemd-nspawn(1).
This enables or disables systemd-nspawn@.service, instantiated for the specified
machine name, similarly to the effect of systemctl enable or systemctl
disable on the service name.
This command implicitly reloads the system manager configuration after completing the operation.
Note that this command does not implicitly start or power off the containers that are being operated on.
If this is desired, combine the command with the --now switch.
NAME…¶Power off one or more containers. This will trigger a shutdown by sending SIGRTMIN+4 to the container's init process, which causes systemd-compatible init systems to shut down cleanly. Use stop as alias for poweroff. This operation does not work on containers that do not run a systemd(1)-compatible init system, such as sysvinit. Use terminate (see below) to immediately terminate a container or VM, without cleanly shutting it down.
NAME…¶Reboot one or more containers. This will trigger a reboot by sending SIGINT to the container's init process, which is roughly equivalent to pressing Ctrl+Alt+Del on a non-containerized system, and is compatible with containers running any system manager.
NAME…¶Immediately terminates a virtual machine or container, without cleanly shutting it down. This kills all processes of the virtual machine or container and deallocates all resources attached to that instance. Use poweroff to issue a clean shutdown request.
NAME…¶Send a signal to one or more processes of the
virtual machine or container. This means processes as seen by
the host, not the processes inside the virtual machine or
container. Use --kill-whom= to select which
process to kill. Use --signal= to select the
signal to send.
NAME PATH [PATH]¶Bind mounts a file or directory from the host into the specified container. The first path
argument is the source file or directory on the host, the second path argument is the destination file or
directory in the container. When the latter is omitted, the destination path in the container is the same as
the source path on the host. When combined with the --read-only switch, a ready-only bind
mount is created. When combined with the --mkdir switch, the destination path is first created
before the mount is applied. Note that this option is currently only supported for
systemd-nspawn(1) containers,
and only if user namespacing (--private-users) is not used. This command supports bind
mounting directories, regular files, device nodes, AF_UNIX socket nodes, as well as
FIFOs.
NAME PATH [PATH] --force¶Copies files or directories from the host system into a running container. Takes a container name, followed by the source path on the host and the destination path in the container. If the destination path is omitted, the same as the source path is used.
If host and container share the same user and group namespace, file ownership by numeric user ID and group ID is preserved for the copy, otherwise all files and directories in the copy will be owned by the root user and group (UID/GID 0).
NAME PATH [PATH] --force¶Copies files or directories from a container into the host system. Takes a container name, followed by the source path in the container and the destination path on the host. If the destination path is omitted, the same as the source path is used.
If host and container share the same user and group namespace, file ownership by numeric user ID and group ID is preserved for the copy, otherwise all files and directories in the copy will be owned by the root user and group (UID/GID 0).
Show a list of locally installed container and
VM images. This enumerates all raw disk images and container
directories and subvolumes in
/var/lib/machines/ (and other search
paths, see below). Use start (see above) to
run a container off one of the listed images. Note that, by
default, containers whose name begins with a dot
(".") are not shown. To show these too,
specify --all. Note that a special image
".host" always implicitly exists and refers
to the image the host itself is booted from.
NAME…]¶Show terse status information about one or more container or VM images. This function is intended to generate human-readable output. Use show-image (see below) to generate computer-parsable output instead.
NAME…]¶Show properties of one or more registered
virtual machine or container images, or the manager itself. If
no argument is specified, properties of the manager will be
shown. If a NAME is specified, properties of this virtual
machine or container image are shown. By default, empty
properties are suppressed. Use --all to show
those too. To select specific properties to show, use
--property=. This command is intended to be
used whenever computer-parsable output is required. Use
image-status if you are looking for
formatted human-readable output.
NAME|FILE¶Edit the settings file of the specified machines. For the format of the settings file, refer to systemd.nspawn(5).
If an existing settings file of the given machine can't be found, edit automatically
create a new settings file from scratch under /etc/systemd/nspawn/
NAME|FILE¶Show the settings file of the specified machines.
NAME NAME¶Clones a container or VM image. The arguments specify the name of the image to clone and the name of the newly cloned image. Note that plain directory container images are cloned into btrfs subvolume images with this command, if the underlying file system supports this. Note that cloning a container or VM image is optimized for file systems that support copy-on-write, and might not be efficient on others, due to file system limitations.
Note that this command leaves hostname, machine ID and all other settings that could identify the instance unmodified. The original image and the cloned copy will hence share these credentials, and it might be necessary to manually change them in the copy.
If combined with the --read-only switch a read-only cloned image is
created.
NAME NAME¶Renames a container or VM image. The arguments specify the name of the image to rename and the new name of the image.
NAME [BOOL]¶Marks or (unmarks) a container or VM image read-only. Takes a VM or container image name, followed by a boolean as arguments. If the boolean is omitted, positive is implied, i.e. the image is marked read-only.
NAME…¶Removes one or more container or VM images.
The special image ".host", which refers to
the host's own directory tree, may not be
removed.
NAME] BYTES¶Sets the maximum size in bytes that a specific
container or VM image, or all images, may grow up to on disk
(disk quota). Takes either one or two parameters. The first,
optional parameter refers to a container or VM image name. If
specified, the size limit of the specified image is changed. If
omitted, the overall size limit of the sum of all images stored
locally is changed. The final argument specifies the size
limit in bytes, possibly suffixed by the usual K, M, G, T
units. If the size limit shall be disabled, specify
"-" as size.
Note that per-container size limits are only supported on btrfs file systems.
Remove hidden VM or container images (or all). This command removes all hidden machine images
from /var/lib/machines/, i.e. those whose name begins with a dot. Use machinectl
list-images --all to see a list of all machine images, including the hidden ones.
When combined with the --all switch removes all images, not just hidden ones. This
command effectively empties /var/lib/machines/.
Note that commands such as machinectl pull-tar or machinectl pull-raw usually create hidden, read-only, unmodified machine images from the downloaded image first, before cloning a writable working copy of it, in order to avoid duplicate downloads in case of images that are reused multiple times. Use machinectl clean to remove old, hidden images created this way.
URL [NAME]¶Downloads a .tar
container image from the specified URL, and makes it available
under the specified local machine name. The URL must be of
type "http://" or
"https://", and must refer to a
.tar, .tar.gz,
.tar.xz or .tar.bz2
archive file. If the local machine name is omitted, it
is automatically derived from the last component of the URL,
with its suffix removed.
The image is verified before it is made available, unless
--verify=no is specified.
Verification is done either via an inline signed file with the name
of the image and the suffix .sha256 or via
separate SHA256SUMS and
SHA256SUMS.gpg files.
The signature files need to be made available on the same web
server, under the same URL as the .tar file.
With --verify=checksum, only the SHA256 checksum
for the file is verified, based on the .sha256
suffixed file or the SHA256SUMS file.
With --verify=signature, the sha checksum file is
first verified with the inline signature in the
.sha256 file or the detached GPG signature file
SHA256SUMS.gpg.
The public key for this verification step needs to be available in
/usr/lib/systemd/import-pubring.gpg or
/etc/systemd/import-pubring.gpg.
The container image will be downloaded and stored in a
read-only subvolume in
/var/lib/machines/ that is named after
the specified URL and its HTTP etag. A writable snapshot is
then taken from this subvolume, and named after the specified
local name. This behavior ensures that creating multiple
container instances of the same URL is efficient, as multiple
downloads are not necessary. In order to create only the
read-only image, and avoid creating its writable snapshot,
specify "-" as local machine name.
Note that the read-only subvolume is prefixed with
.tar-, and is thus not shown by
list-images, unless --all
is passed.
Note that pressing C-c during execution of this command will not abort the download. Use cancel-transfer, described below.
URL [NAME]¶Downloads a .raw
container or VM disk image from the specified URL, and makes
it available under the specified local machine name. The URL
must be of type "http://" or
"https://". The container image must either
be a .qcow2 or raw disk image, optionally
compressed as .gz,
.xz, or .bz2. If the
local machine name is omitted, it is automatically
derived from the last component of the URL, with its suffix
removed.
Image verification is identical for raw and tar images (see above).
If the downloaded image is in
.qcow2 format it is converted into a raw
image file before it is made available.
Downloaded images of this type will be placed as
read-only .raw file in
/var/lib/machines/. A local, writable
(reflinked) copy is then made under the specified local
machine name. To omit creation of the local, writable copy
pass "-" as local machine name.
Similarly to the behavior of pull-tar, the read-only image is prefixed with
.raw-, and thus not shown by list-images, unless
--all is passed.
Note that pressing C-c during execution of this command will not abort the download. Use cancel-transfer, described below.
FILE [NAME], import-raw FILE [NAME]¶Imports a TAR or RAW container or VM image,
and places it under the specified name in
/var/lib/machines/. When
import-tar is used, the file specified as
the first argument should be a tar archive, possibly compressed
with xz, gzip or bzip2. It will then be unpacked into its own
subvolume in /var/lib/machines/. When
import-raw is used, the file should be a
qcow2 or raw disk image, possibly compressed with xz, gzip or
bzip2. If the second argument (the resulting image name) is
not specified, it is automatically derived from the file
name. If the filename is passed as "-", the
image is read from standard input, in which case the second
argument is mandatory.
Optionally, the --read-only switch may be used to create a read-only container or VM
image. No cryptographic validation is done when importing the images.
Much like image downloads, ongoing imports may be listed with list-transfers and aborted with cancel-transfer.
DIRECTORY [NAME]¶Imports a container image stored in a local directory into
/var/lib/machines/, operates similarly to import-tar or
import-raw, but the first argument is the source directory. If supported, this
command will create a btrfs snapshot or subvolume for the new image.
NAME [FILE], export-raw NAME [FILE]¶Exports a TAR or RAW container or VM image and
stores it in the specified file. The first parameter should be
a VM or container image name. The second parameter should be a
file path the TAR or RAW image is written to. If the path ends
in ".gz", the file is compressed with gzip, if
it ends in ".xz", with xz, and if it ends in
".bz2", with bzip2. If the path ends in
neither, the file is left uncompressed. If the second argument
is missing, the image is written to standard output. The
compression may also be explicitly selected with the
--format= switch. This is in particular
useful if the second parameter is left unspecified.
Much like image downloads and imports, ongoing exports may be listed with list-transfers and aborted with cancel-transfer.
Note that, currently, only directory and subvolume images may be exported as TAR images, and only raw disk images as RAW images.
Shows a list of container or VM image downloads, imports and exports that are currently in progress.
ID…¶Aborts a download, import or export of the container or VM image with the specified ID. To list ongoing transfers and their IDs, use list-transfers.
The following options are understood:
-p, --property=¶When showing machine or image properties,
limit the output to certain properties as specified by the
argument. If not specified, all set properties are shown. The
argument should be a property name, such as
"Name". If specified more than once, all
properties with the specified names are
shown.
-a, --all¶When showing machine or image properties, show all properties regardless of whether they are set or not.
When listing VM or container images, do not suppress
images beginning in a dot character
(".").
When cleaning VM or container images, remove all images, not just hidden ones.
--value¶When printing properties with show, only print the value,
and skip the property name and "=".
-l, --full¶Do not ellipsize process tree entries or table. This implies
--max-addresses=full.
--kill-whom=¶When used with kill, choose
which processes to kill. Must be one of
leader, or all to select
whether to kill only the leader process of the machine or all
processes of the machine. If omitted, defaults to
all.
-s, --signal=¶When used with kill, choose which signal to send to selected processes. Must
be one of the well-known signal specifiers such as SIGTERM,
SIGINT or SIGSTOP. If omitted, defaults to
SIGTERM.
The special value "help" will list the known values and the program will exit
immediately, and the special value "list" will list known values along with the
numerical signal numbers and the program will exit immediately.
--uid=¶When used with the shell command, chooses the user ID to
open the interactive shell session as. If the argument to the shell
command also specifies a user name, this option is ignored. If the name is not specified
in either way, "root" will be used by default. Note that this switch is
not supported for the login command (see below).
-E NAME[=VALUE], --setenv=NAME[=VALUE]¶When used with the shell command, sets an environment variable for
the executed shell. This option may be used more than once to set multiple variables. When
"=" and VALUE are omitted, the value of the variable with
the same name in the program environment will be used.
Note that this option is not supported for the login command.
--mkdir¶When used with bind, creates the destination file or directory before applying the bind mount. Note that even though the name of this option suggests that it is suitable only for directories, this option also creates the destination file node to mount over if the object to mount is not a directory, but a regular file, device node, socket or FIFO.
--read-only¶When used with bind, creates a read-only bind mount.
When used with clone, import-raw or import-tar a read-only container or VM image is created.
-n, --lines=¶When used with status, controls the number of journal lines to show, counting from the most recent ones. Takes a positive integer argument. Defaults to 10.
-o, --output=¶When used with status,
controls the formatting of the journal entries that are shown.
For the available choices, see
journalctl(1).
Defaults to "short".
--verify=¶When downloading a container or VM image,
specify whether the image shall be verified before it is made
available. Takes one of "no",
"checksum" and "signature".
If "no", no verification is done. If
"checksum" is specified, the download is
checked for integrity after the transfer is complete, but no
signatures are verified. If "signature" is
specified, the checksum is verified and the image's signature
is checked against a local keyring of trustable vendors. It is
strongly recommended to set this option to
"signature" if the server and protocol
support this. Defaults to
"signature".
--now¶When used with enable or disable, the containers will also be started or powered off. The start or poweroff operation is only carried out when the respective enable or disable operation has been successful.
--force¶When downloading a container or VM image, and a local copy by the specified local machine name already exists, delete it first and replace it by the newly downloaded image.
--format=¶When used with the export-tar
or export-raw commands, specifies the
compression format to use for the resulting file. Takes one of
"uncompressed", "xz",
"gzip", "bzip2". By default,
the format is determined automatically from the image file
name passed.
--max-addresses=¶When used with the list-machines command, limits the number of IP
addresses shown for every machine. Defaults to 1. All addresses can be requested with
"all". If the limit is 0, the address column is not shown. Otherwise, if the machine
has more addresses than shown, "…" follows the last address.
-q, --quiet¶Suppresses additional informational output while running.
-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=¶Connect to systemd-machined.service(8) running in a local container, to perform the specified operation within the container.
--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¶--version¶The machinectl tool operates on machines and images whose names must be chosen following strict rules. Machine names must be suitable for use as hostnames following a conservative subset of DNS and UNIX/Linux semantics. Specifically, they must consist of one or more non-empty label strings, separated by dots. No leading or trailing dots are allowed. No sequences of multiple dots are allowed. The label strings may only consist of alphanumeric characters as well as the dash and underscore. The maximum length of a machine name is 64 characters.
A special machine with the name ".host"
refers to the running host system itself. This is useful for execution
operations or inspecting the host system as well. Note that
machinectl list will not show this special
machine unless the --all switch is specified.
Requirements on image names are less strict, however, they must be valid UTF-8, must be suitable as file names (hence not be the single or double dot, and not include a slash), and may not contain control characters. Since many operations search for an image by the name of a requested machine, it is recommended to name images in the same strict fashion as machines.
A special image with the name ".host"
refers to the image of the running host system. It hence
conceptually maps to the special ".host" machine
name described above. Note that machinectl
list-images will not show this special image either, unless
--all is specified.
Machine images are preferably stored in
/var/lib/machines/, but are also searched for
in /usr/local/lib/machines/ and
/usr/lib/machines/. For compatibility reasons,
the directory /var/lib/container/ is
searched, too. Note that images stored below
/usr/ are always considered read-only. It is
possible to symlink machines images from other directories into
/var/lib/machines/ to make them available for
control with machinectl.
Note that some image operations are only supported, efficient or atomic on btrfs file systems.
Disk images are understood by systemd-nspawn(1) and machinectl in three formats:
A simple directory tree, containing the files and directories of the container to boot.
Subvolumes (on btrfs file systems), which are similar to the simple directories, described above. However, they have additional benefits, such as efficient cloning and quota reporting.
"Raw" disk images, i.e. binary images of disks
with a GPT or MBR partition table. Images of this type are
regular files with the suffix
".raw".
See
systemd-nspawn(1)
for more information on image formats, in particular its
--directory= and --image=
options.
Example 1. Download a Ubuntu image and open a shell in it
# machinectl pull-tar https://cloud-images.ubuntu.com/trusty/current/trusty-server-cloudimg-amd64-root.tar.gz # systemd-nspawn -M trusty-server-cloudimg-amd64-root
This downloads and verifies the specified
.tar image, and then uses
systemd-nspawn(1)
to open a shell in it.
Example 2. Download a Fedora image, set a root password in it, start it as a service
# machinectl pull-raw --verify=no \
https://download.fedoraproject.org/pub/fedora/linux/releases/40/Cloud/x86_64/images/Fedora-Cloud-Base-40-1.6.x86_64.raw.xz \
Fedora-Cloud-Base-40-1.6.x86-64
# systemd-nspawn -M Fedora-Cloud-Base-40-1.6.x86-64
# passwd
# exit
# machinectl start Fedora-Cloud-Base-40-1.6.x86-64
# machinectl login Fedora-Cloud-Base-40-1.6.x86-64This downloads the specified .raw
image with verification disabled. Then, a shell is opened in it
and a root password is set. Afterwards the shell is left, and
the machine started as system service. With the last command a
login prompt into the container is requested.
Example 3. Exports a container image as tar file
# machinectl export-tar fedora myfedora.tar.xz
Exports the container "fedora" as an
xz-compressed tar file myfedora.tar.xz into the
current directory.
Example 4. Create a new shell session
# machinectl shell --uid=lennart
This creates a new shell session on the local host for
the user ID "lennart", in a su(1)-like
fashion.
$SYSTEMD_LOG_LEVEL¶The maximum log level of emitted messages (messages with a higher
log level, i.e. less important ones, will be suppressed). 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.
$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¶Pager to use when --no-pager is not given.
$SYSTEMD_PAGER is used if set; otherwise $PAGER is used.
If neither $SYSTEMD_PAGER nor $PAGER are set, a set of well-known
pager implementations is tried in turn, including
less(1)
and
more(1),
until one is found. If no pager implementation is discovered, no pager is invoked. Setting those
environment variables to an empty string or the value "cat" is equivalent to passing
--no-pager.
Note: if $SYSTEMD_PAGERSECURE is not set, $SYSTEMD_PAGER
and $PAGER can only be used to disable the pager (with "cat" or
""), and are otherwise ignored.
$SYSTEMD_LESS¶Override the options passed to less (by default
"FRSXMK").
Users might want to change two options in particular:
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¶Common pager commands like less(1), in
addition to "paging", i.e. scrolling through the output, support opening of or writing to other files
and running arbitrary shell commands. When commands are invoked with elevated privileges, for example
under sudo(8) or
pkexec(1), the
pager becomes a security boundary. Care must be taken that only programs with strictly limited
functionality are used as pagers, and unintended interactive features like opening or creation of new
files or starting of subprocesses are not allowed. "Secure mode" for the pager may be enabled as
described below, if the pager supports that (most pagers are not written in a way
that takes this into consideration). It is recommended to either explicitly enable "secure mode" or to
completely disable the pager using --no-pager or PAGER=cat when
allowing untrusted users to execute commands with elevated privileges.
This option takes a boolean argument. When set to true, the "secure mode" of the pager is
enabled. In "secure mode", LESSSECURE=1 will be set when invoking the pager, which
instructs the pager to disable commands that open or create new files or start new subprocesses.
Currently only less(1) is known
to understand this variable and implement "secure mode".
When set to false, no limitation is placed on the pager. Setting
SYSTEMD_PAGERSECURE=0 or not removing it from the inherited environment may allow
the user to invoke arbitrary commands.
When $SYSTEMD_PAGERSECURE is not set, systemd tools attempt to automatically
figure out if "secure mode" should be enabled and whether the pager supports it. "Secure mode" is
enabled if the effective UID is not the same as the owner of the login session, see
geteuid(2)
and
sd_pid_get_owner_uid(3),
or when running under
sudo(8) or similar
tools ($SUDO_UID is set [1]). In those cases,
SYSTEMD_PAGERSECURE=1 will be set and pagers which are not known to implement
"secure mode" will not be used at all. Note that this autodetection only covers the most common
mechanisms to elevate privileges and is intended as convenience. It is recommended to explicitly set
$SYSTEMD_PAGERSECURE or disable the pager.
Note that if the $SYSTEMD_PAGER or $PAGER variables are to
be honoured, other than to disable the pager, $SYSTEMD_PAGERSECURE must be set
too.
$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.
systemd(1), systemd-machined.service(8), systemd-nspawn(1), systemd.special(7), tar(1), xz(1), gzip(1), bzip2(1)
[1] It is recommended for other tools to set and check $SUDO_UID as appropriate,
treating it is a common interface.