NAME¶
portablectl - Attach, detach or inspect portable service
images
SYNOPSIS¶
portablectl [OPTIONS...] {COMMAND} [NAME...]
DESCRIPTION¶
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[1].
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.)
COMMANDS¶
The following commands are understood:
list
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.
Added in version 239.
attach 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:
1.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.
2.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.
3.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.
4.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.
Added in version 239.
detach 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.
Added in version 239.
reattach 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.
Added in version 248.
inspect 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.
Added in version 239.
is-attached 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. |
Added in version 239.
read-only 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.
Added in version 239.
remove 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.
Added in version 239.
set-limit [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.
Added in version 239.
OPTIONS¶
The following options are understood:
-q, --quiet
Suppresses additional informational output while running.
Added in version 239.
-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.
Added in version 239.
--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.
Added in version 239.
--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.
Added in version 239.
--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.
Added in version 239.
--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.
Added in version 239.
--enable
Immediately enable/disable the portable service after
attaching/detaching.
Added in version 245.
--now
Immediately start/stop/restart the portable service after
attaching/before detaching/after upgrading.
Added in version 245.
--no-block
Don't block waiting for attach --now to complete.
Added in version 245.
--clean
When detaching ensure the configuration, state, logs,
cache, and runtime data directories of the portable service are removed from
the host system.
Added in version 256.
--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[1].
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.
Added in version 249.
--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.
NAME file in the extension image has
to match the image filename.
Added in version 252.
-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
Print a short help text and exit.
--version
Print a short version string and exit.
FILES AND DIRECTORIES¶
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.
PROFILES¶
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.
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 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.
NOTES¶
- 1.
- Portable Services