portablectl — Attach, detach or inspect portable service images
portablectl [OPTIONS...] {COMMAND} [NAME...]
portablectl may be used to attach, detach or inspect portable service images. It's primarily a command interfacing with systemd-portabled.service(8).
Portable service images contain an OS file system tree along with
systemd(1) unit file
information. A service image may be "attached" to the local system. If attached, a set of unit files are copied
from the image to the host, and extended with RootDirectory= or RootImage=
assignments (in case of service units) pointing to the image file or directory, ensuring the services will run
within the file system context of the image.
Portable service images are an efficient way to bundle multiple related services and other units together, and transfer them as a whole between systems. When these images are attached to the local system, the contained units may run in most ways like regular system-provided units, either with full privileges or inside strict sandboxing, depending on the selected configuration. For more details, see Portable Services.
Portable service images may be of the following kinds:
Directory trees containing an OS, including the top-level directories /usr/,
/etc/, and so on.
btrfs subvolumes containing OS trees, similar to normal directory trees.
Binary "raw" disk images containing MBR or GPT partition tables and Linux file system
partitions. (These must be regular files, with the .raw suffix.)
The following commands are understood:
List available portable service images. This will list all portable service images discovered in the portable image search paths (see below), along with brief metadata and state information. Note that many of the commands below may both operate on images inside and outside of the search paths. This command is hence mostly a convenience option, the commands are generally not restricted to what this list shows.
IMAGE [PREFIX…]¶Attach a portable service image to the host system. Expects a file system path to a portable
service image file or directory as first argument. If the specified path contains no slash character
("/") it is understood as image filename that is searched for in the portable service image
search paths (see below). To reference a file in the current working directory prefix the filename with
"./" to avoid this search path logic.
When a portable service is attached four operations are executed:
All unit files of types .service, .socket,
.target, .timer and .path which match the
indicated unit file name prefix are copied from the image to the host's
/etc/systemd/system.attached/ directory (or
/run/systemd/system.attached/ — depending whether --runtime is
specified, see below), which is included in the built-in unit search path of the system service
manager.
For unit files of type .service a drop-in is added to these copies that
adds RootDirectory= or RootImage= settings (see
systemd.unit(5) for
details), that ensures these services are run within the file system of the originating portable service
image.
A second drop-in is created: the "profile" drop-in, that may contain additional security settings (and other settings). A number of profiles are available by default but administrators may define their own ones. See below.
If the portable service image file is not already in the search path (see below), a symbolic
link to it is created in /etc/portables/ or
/run/portables/, to make sure it is included in it.
By default all unit files whose names start with a prefix generated from the image's file name are copied
out. Specifically, the prefix is determined from the image file name with any suffix such as
.raw removed, truncated at the first occurrence of an underscore character
("_"), if there is one. The underscore logic is supposed to be used to versioning so that the
an image file foobar_47.11.raw will result in a unit file matching prefix of
foobar. This prefix is then compared with all unit files names contained in the image in
the usual directories, but only unit file names where the prefix is followed by "-",
"." or "@" are considered. Example: if a portable service image file is named
foobar_47.11.raw then by default all its unit files with names such as
foobar-quux-waldi.service, foobar.service or
foobar@.service will be considered. It's possible to override the matching prefix: all
strings listed on the command line after the image file name are considered prefixes, overriding the implicit
logic where the prefix is derived from the image file name.
By default, after the unit files are attached the service manager's configuration is reloaded, except
when --no-reload is specified (see below). This ensures that the new units made available to
the service manager are seen by it.
If --now and/or --enable are passed, the portable services are
immediately started (blocking operation unless --no-block is passed) and/or enabled after
attaching the image.
In place of the image path a ".v/" versioned directory may be specified, see
systemd.v(7) for
details.
In place of the directory path a ".v/" versioned directory may be specified,
see systemd.v(7) for
details.
IMAGE [PREFIX…]¶Detaches a portable service image from the host. This undoes the operations executed by the attach command above, and removes the unit file copies, drop-ins and image symlink again. This command expects an image name or path as parameter. Note that if a path is specified only the last component of it (i.e. the file or directory name itself, not the path to it) is used for finding matching unit files. This is a convenience feature to allow all arguments passed as attach also to detach.
If --now and/or --enable are passed, the portable services are
immediately stopped (blocking operation) and/or disabled before detaching the image. Prefix(es) are also accepted,
to be used in case the unit names do not match the image name as described in the attach.
IMAGE [PREFIX…]¶Detaches an existing portable service image from the host, and immediately attaches it again.
This is useful in case the image was replaced. Running units are not stopped during the process. Partial matching,
to allow for different versions in the image name, is allowed: only the part before the first "_"
character has to match. If the new image doesn't exist, the existing one will not be detached. The parameters
follow the same syntax as the attach command.
If --now and/or --enable are passed, the portable services are
immediately stopped if removed, started and/or enabled if added, or restarted if updated. Prefixes are also
accepted, in the same way as described in the attach case.
IMAGE [PREFIX…]¶Extracts various metadata from a portable service image and presents it to the
caller. Specifically, the
os-release(5) file of the
image is retrieved as well as all matching unit files. By default a short summary showing the most relevant
metadata in combination with a list of matching unit files is shown (that is the unit files
attach would install to the host system). If combined with --cat (see
above), the os-release data and the units files' contents is displayed unprocessed. This
command is useful to determine whether an image qualifies as portable service image, and which unit files are
included. This command expects the path to the image as parameter, optionally followed by a list of unit file
prefixes to consider, similar to the attach command described above.
IMAGE¶Determines whether the specified image is currently attached or not. Unless combined with the
--quiet switch this will show a short state identifier for the image. Specifically:
Table 1. Image attachment states
| State | Description |
|---|---|
detached | The image is currently not attached. |
attached | The image is currently attached, i.e. its unit files have been made available to the host system. |
attached-runtime | Like attached, but the unit files have been made available transiently only, i.e. the attach command has been invoked with the --runtime option. |
enabled | The image is currently attached, and at least one unit file associated with it has been enabled. |
enabled-runtime | Like enabled, but the unit files have been made available transiently only, i.e. the attach command has been invoked with the --runtime option. |
running | The image is currently attached, and at least one unit file associated with it is running. |
running-runtime | The image is currently attached transiently, and at least one unit file associated with it is running. |
IMAGE [BOOL]¶Marks or (unmarks) a portable service image read-only. Takes an image name, followed by a boolean as arguments. If the boolean is omitted, positive is implied, i.e. the image is marked read-only.
IMAGE…¶Removes one or more portable service images. Note that this command will only remove the specified image path itself — it refers to a symbolic link then the symbolic link is removed and not the image it points to.
IMAGE] BYTES¶Sets the maximum size in bytes that a specific portable service 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
portable service 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-image size limits are only supported on btrfs file systems. Also, depending on
BindPaths= settings in the portable service's unit files directories from the host might be
visible in the image environment during runtime which are not affected by this setting, as only the image
itself is counted against this limit.
The following options are understood:
-q, --quiet¶Suppresses additional informational output while running.
-p PROFILE, --profile=PROFILE¶When attaching an image, select the profile to use. By default the "default"
profile is used. For details about profiles, see below.
--copy=¶When attaching an image, select whether to prefer copying or symlinking of files
installed into the host system. Takes one of "copy" (files will be copied),
"symlink" (to prefer creation of symbolic links), "auto" for an
intermediary mode where security profile drop-ins and images are symlinked while unit files are
copied, or "mixed" (since v256) where security profile drop-ins are symlinked while
unit files and images are copied. Note that this option expresses a preference only, in cases where
symbolic links cannot be created — for example when the image operated on is a raw disk image, and
hence not directly referentiable from the host file system — copying of files is used
unconditionally.
--runtime¶When specified the unit and drop-in files are placed in
/run/systemd/system.attached/ instead of
/etc/systemd/system.attached/. Images attached with this option set hence remain attached
only until the next reboot, while they are normally attached persistently.
--no-reload¶Don't reload the service manager after attaching or detaching a portable service image. Normally the service manager is reloaded to ensure it is aware of added or removed unit files.
--cat¶When inspecting portable service images, show the (unprocessed) contents of the metadata files pulled from the image, instead of brief summaries. Specifically, this will show the os-release(5) and unit file contents of the image.
--enable¶Immediately enable/disable the portable service after attaching/detaching.
--now¶Immediately start/stop/restart the portable service after attaching/before detaching/after upgrading.
--no-block¶Don't block waiting for attach --now to complete.
--clean¶When detaching ensure the configuration, state, logs, cache, and runtime data directories of the portable service are removed from the host system.
--extension=PATH¶Add an additional image PATH as an overlay on
top of IMAGE when attaching/detaching. This argument can be specified
multiple times, in which case the order in which images are laid down follows the rules specified in
systemd.exec(5)
for the ExtensionImages= directive and for the
systemd-sysext(8) and
systemd-confext(8) tools.
The images must contain an extension-release file with metadata that matches
what is defined in the os-release of IMAGE. See:
os-release(5).
Images can be block images, btrfs subvolumes or directories. For more information on portable
services with extensions, see the "Extension Images" paragraph on
Portable Services.
Note that the same extensions have to be specified, in the same order, when attaching and detaching.
In place of the image path a ".v/" versioned directory may be specified, see
systemd.v(7) for
details.
In place of the directory path a ".v/" versioned directory may be specified,
see systemd.v(7) for
details.
--force¶Skip safety checks and attach or detach images (with extensions) without first ensuring
that the units are not running, and do not insist that the
extension-release. file in the extension image has
to match the image filename.NAME
-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
--machine=lennart@.host"). 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¶--version¶Portable service images are preferably stored in /var/lib/portables/, but are also
searched for in /etc/portables/, /run/systemd/portables/,
/usr/local/lib/portables/ and /usr/lib/portables/. It's recommended not
to place image files directly in /etc/portables/ or
/run/systemd/portables/ (as these are generally not suitable for storing large or non-textual
data), but use these directories only for linking images located elsewhere into the image search path.
When a portable service image is attached, matching unit files are copied onto the host into the
/etc/systemd/system.attached/ and /run/systemd/system.attached/
directories. When an image is detached, the unit files are removed again from these directories.
When portable service images are attached a "profile" drop-in is linked in, which may be used to enforce
additional security (and other) restrictions locally. Four profile drop-ins are defined by default, and shipped in
/usr/lib/systemd/portable/profile/. Additional, local profiles may be defined by placing them
in /etc/systemd/portable/profile/. The default profiles are:
Table 2. Profiles
| Name | Description |
|---|---|
default | This is the default profile if no other profile name is set via the --profile= (see above). It's fairly restrictive, but should be useful for common, unprivileged system workloads. This includes write access to the logging framework, as well as IPC access to the D-Bus system. |
nonetwork | Very similar to default, but networking is turned off for any services of the portable service image. |
strict | A profile with very strict settings. This profile excludes IPC (D-Bus) and network access. |
trusted | A profile with very relaxed settings. In this profile the services run with full privileges. |
For details on these profiles and their effects see their precise definitions,
e.g. /usr/lib/systemd/portable/profile/default/service.conf and similar.
$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.