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:
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/ |
The following commands are understood:
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 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.
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.
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.
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.
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.
Shows a list of image downloads, imports and exports that are currently in progress.
ID
…¶Aborts a download, import or export of the image with the specified ID. To list ongoing transfers and their IDs, use list.
Shows a list of already downloaded/imported images.
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.
--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
".
--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.
--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.
-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-import.service(8) running in a local container, to perform the specified operation within the container.
--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.
--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
.
--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
¶--version
¶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.
$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.