PORTABLECTL(1) portablectl PORTABLECTL(1)
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 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.
Specifically portable service images may be of the following kind:
o Directory trees containing an OS, including the top-level
directories /usr/, /etc/, and so on.
o btrfs subvolumes containing OS trees, similar to normal directory
trees.
o Binary "raw" disk images containing MBR or GPT partition tables and
Linux file system partitions.
OPTIONS
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" (to prefer copying of files), "symlink" (to prefer creation
of symbolic links) or "auto" for an intermediary mode where
security profile drop-ins are symlinked while unit files 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/ instead of /etc/systemd/system/. 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.
-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 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.
-M, --machine=
Execute operation on a local container. Specify a container name to
connect to.
--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.
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.
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/
directory (or /run/systemd/system/ -- depending whether
--runtime is specified, see above).
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 and 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 above). This ensures that the new units made available to the
service manager are seen by it.
detach IMAGE
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 convencience feature to allow all arguments passed
as attach also to detach.
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.
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 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. |
+-----------------+----------------------------+
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.
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.
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.
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.
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 this profiles, and their effects please have a look at
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_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.
$SYSTEMD_LESS
Override the options passed to less (by default "FRSXMK").
$SYSTEMD_LESSCHARSET
Override the charset passed to less (by default "utf-8", if the
invoking terminal is determined to be UTF-8 compatible).
$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
completly disable the pager using --no-pager instead.
SEE ALSO
systemd(1), systemd-portabled.service(8)
systemd 239 PORTABLECTL(1)
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