importctl - Download, import or export disk images
importctl [OPTIONS...] {COMMAND} [NAME...]
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:
•Portable service images, that may be attached and
managed via
portablectl(1).
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/ |
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.
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-import.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.
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.
On success, 0 is returned, a non-zero failure code otherwise.
$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.
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)