IMPORTCTL(1) importctl IMPORTCTL(1)
NAME
importctl - Download, import or export disk images
SYNOPSIS
importctl [OPTIONS...] {COMMAND} [NAME...]
DESCRIPTION
importctl may be used to download, import, and export disk images via
systemd-importd.service(8).
importctl operates both on block-level disk images (such as DDIs) as
well as file-system-level images (tarballs). It supports disk images in
one of the four following classes:
• VM images or full OS container images, that may be run via systemd-
vmspawn(1) or systemd-nspawn(1), and managed via machinectl(1).
• Portable service images, that may be attached and managed via
portablectl(1).
• System extension (sysext) images, that may be activated via systemd-
sysext(8).
• Configuration extension (confext) images, that may be activated via
systemd-confext(8).
When images are downloaded or imported they are placed in the following
directories, depending on the --class= parameter:
Table 1. Classes and Directories
┌────────────┬──────────────────────┐
│ Class │ Directory │
├────────────┼──────────────────────┤
│ "machine" │ /var/lib/machines/ │
├────────────┼──────────────────────┤
│ "portable" │ /var/lib/portables/ │
├────────────┼──────────────────────┤
│ "sysext" │ /var/lib/extensions/ │
├────────────┼──────────────────────┤
│ "confext" │ /var/lib/confexts/ │
└────────────┴──────────────────────┘
COMMANDS
The following commands are understood:
pull-tar URL [NAME]
Downloads a .tar image from the specified URL, and makes it
available under the specified local name in the image directory for
the selected --class=. 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 image 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.
If -keep-download=yes is specified the image will be downloaded and
stored in a read-only subvolume/directory in the image directory
that is named after the specified URL and its HTTP etag (see HTTP
ETag[1] for more information). A writable snapshot is then taken
from this subvolume, and named after the specified local name. This
behavior ensures that creating multiple 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 name.
Note that pressing Control-c during execution of this command will
not abort the download. Use cancel-transfer, described below.
Added in version 256.
pull-raw URL [NAME]
Downloads a .raw disk image from the specified URL, and makes it
available under the specified local name in the image directory for
the selected --class=. The URL must be of type "http://" or
"https://". The image must either be a qcow2 or raw disk image,
optionally compressed as .gz, .xz, or .bz2. If the local 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.
If -keep-download=yes is specified the image will be downloaded and
stored in a read-only file in the image directory that is named
after the specified URL and its HTTP etag. A writable copy is then
made from this file, and named after the specified local name. This
behavior ensures that creating multiple 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
copy, specify "-" as local name.
Note that pressing Control-c during execution of this command will
not abort the download. Use cancel-transfer, described below.
Added in version 256.
import-tar FILE [NAME], import-raw FILE [NAME]
Imports a TAR or RAW image, and places it under the specified name
in the image directory for the image class selected via --class=.
When import-tar is used, the file specified as the first argument
should be a tar(1) archive, possibly compressed with xz(1), gzip(1),
or bzip2(1). It will then be unpacked into its own
subvolume/directory. 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.
No cryptographic validation is done when importing the images.
Much like image downloads, ongoing imports may be listed with list
and aborted with cancel-transfer.
Added in version 256.
import-fs DIRECTORY [NAME]
Imports an image stored in a local directory into the image
directory for the image class selected via --class= and operates
similarly to import-tar or import-raw, but the first argument is the
source directory. If supported, this command will create a btrfs(8)
snapshot or subvolume for the new image.
Added in version 256.
export-tar NAME [FILE], export-raw NAME [FILE]
Exports a TAR or RAW image and stores it in the specified file. The
first parameter should be an 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(1), if it ends in ".xz",
with xz(1), and if it ends in ".bz2", with bzip2(1). 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 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.
Added in version 256.
list-transfer
Shows a list of image downloads, imports and exports that are
currently in progress.
Added in version 256.
cancel-transfer ID...
Aborts a download, import or export of the image with the specified
ID. To list ongoing transfers and their IDs, use list.
Added in version 256.
list-images
Shows a list of already downloaded/imported images.
Added in version 256.
OPTIONS
The following options are understood:
--read-only
When used with pull-raw, pull-tar, import-raw, import-tar or
import-fs a read-only image is created.
Added in version 256.
--verify=
When downloading an 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".
Added in version 256.
--force
When downloading an image, and a local copy by the specified local
name already exists, delete it first and replace it by the newly
downloaded image.
Added in version 256.
--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 output image file name passed.
Added in version 256.
-q, --quiet
Suppresses additional informational output while running.
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=
Connect to systemd-importd.service(8) running in a local container,
to perform the specified operation within the container.
Added in version 256.
--class=, -m, -P, -S, -C
Selects the image class for the downloaded images. This primarily
selects the directory to download into. The --class= switch takes
"machine", "portable", "sysext" or "confext" as argument. The short
options -m, -P, -S, -C are shortcuts for --class=machine,
--class=portable, --class=sysext, --class=confext.
Note that --keep-download= defaults to true for --class=machine and
false otherwise, see below.
Added in version 256.
--keep-download=, -N
Takes a boolean argument. When specified with pull-raw or pull-tar,
selects whether to download directly into the specified local image
name, or whether to download into a read-only copy first of which to
make a writable copy after the download is completed. Defaults to
true for --class=machine, false otherwise.
The -N switch is a shortcut for --keep-download=no.
Added in version 256.
--json=MODE
Shows output formatted as JSON. Expects one of "short" (for the
shortest possible output without any redundant whitespace or line
breaks), "pretty" (for a pretty version of the same, with
indentation and line breaks) or "off" (to turn off JSON output, the
default).
-j
Equivalent to --json=pretty if running on a terminal, and
--json=short otherwise.
--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.
EXAMPLES
Example 1. Download an Ubuntu TAR image and open a shell in it
# importctl pull-tar -mN https://cloud-images.ubuntu.com/jammy/current/jammy-server-cloudimg-amd64-root.tar.xz
# systemd-nspawn -M jammy-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 an Ubuntu RAW image, set a root password in it,
start it as a service
# importctl pull-raw -mN \
https://cloud-images.ubuntu.com/jammy/current/jammy-server-cloudimg-amd64-disk-kvm.img \
jammy
# systemd-firstboot --image=/var/lib/machines/jammy.raw --prompt-root-password --force
# machinectl start jammy
# machinectl login jammy
This downloads the specified .raw image and makes it available under the
local name "jammy". Then, a root password is set with systemd-
firstboot(1). Afterwards the machine is 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
# importctl export-tar -m fedora myfedora.tar.xz
Exports the container "fedora" as an xz-compressed tar file
myfedora.tar.xz into the current directory.
EXIT STATUS
On success, 0 is returned, a non-zero failure code otherwise.
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
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:
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
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 [2]). 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.
SEE ALSO
systemd(1), systemd-importd.service(8), systemd-nspawn(1), systemd-
vmspawn(1), machinectl(1), portablectl(1), systemd-sysext(8), systemd-
confext(8), tar(1), xz(1), gzip(1), bzip2(1)
NOTES
1. HTTP ETag
https://en.wikipedia.org/wiki/HTTP_ETag
2. It is recommended for other tools to set and check $SUDO_UID as
appropriate, treating it is a common interface.
systemd 257.9 IMPORTCTL(1)
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