STORAGECTL(1)

NAME
storagectl, mount.storage - Enumerate and mount storage volumes provided by storage providers

SYNOPSIS

storagectl [OPTIONS...] {COMMAND} [NAME...]

mount -t storage PROVIDER:VOLUME DIRECTORY

mount -t storage.FSTYPE PROVIDER:VOLUME DIRECTORY

DESCRIPTION

storagectl may be used to inspect storage providers and the storage volumes they expose. A storage provider is a service implementing the io.systemd.StorageProvider Varlink[1] interface, registered as an AF_UNIX socket below the well-known socket directory /run/systemd/io.systemd.StorageProvider/ (in system mode) or $XDG_RUNTIME_DIR/systemd/io.systemd.StorageProvider/ (in user mode). The two storage providers shipped with systemd are systemd-storage-block@.service(8), which exposes the system's block devices, and systemd-storage-fs@.service(8), which exposes regular files and directories from a backing file system.

The tool also provides a mount(8) helper for the file system type "storage", which permits mounting storage volumes to arbitrary places. See "Use as a mount helper" below for details.

COMMANDS

The following commands are understood:

volumes [GLOB]
    List storage volumes provided by all storage providers running on the system (or, with --user, in the user runtime). The optional GLOB argument is a shell-style pattern (see fnmatch(3)) that filters the result by volume name. The output is a table containing the providing service, the volume name, its type ("blk", "reg" or "dir"), whether it is read-only, and — if known — its size and the number of bytes used.

    This is the default command if none is specified.

    Added in version 261.

templates [GLOB]
    List volume templates supported by the running storage providers. Templates encapsulate a configuration to use when creating volumes on-the-fly, when they are acquired. Template support is an optional feature for providers, and only applies to providers that allow creation of volumes on-the-fly. See the respective provider documentation for details, for example systemd-storage-fs@.service(8). The optional GLOB argument filters by template name. Storage providers that do not implement template-based volume creation (such as the block-device provider) do not contribute to this output.

    Added in version 261.

providers
    List the storage providers known to the system. This is determined by scanning the well-known socket directory for AF_UNIX sockets that look like io.systemd.StorageProvider endpoints. For each provider it is also reported whether the socket can currently be connected to.

    Added in version 261.

OPTIONS

The following options are understood:

--system
    Operate on system-wide storage providers. Sockets are looked for in /run/systemd/io.systemd.StorageProvider/. This is the default.

    Added in version 261.

--user
    Operate on per-user storage providers. Sockets are looked for in $XDG_RUNTIME_DIR/systemd/io.systemd.StorageProvider/.

    Added in version 261.

--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).

--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.

USE AS A MOUNT HELPER

The tool provides the /sbin/mount.storage alias, implementing the mount(8) "external helper" interface, allowing storage volumes to be mounted with the regular mount command. The volume to mount is encoded as the source of the mount, in the form "PROVIDER:VOLUME", where PROVIDER is the name of a storage provider (as listed by storagectl providers) and VOLUME is the volume name. Two file system type spellings are recognized:

"storage"
    Acquires a directory volume and bind-mounts its directory tree onto the target.

    Added in version 261.

"storage.FSTYPE"
    Acquires a regular file or block device volume and mounts it as a file system of type FSTYPE (for example "storage.ext4", "storage.btrfs", ...).

    Added in version 261.

The standard -o mount options are forwarded to mount. In addition, the following "storage."-prefixed options are interpreted by mount.storage itself and stripped from the forwarded list:

storage.create=MODE
    Takes one of "any" (open if it exists, otherwise create — the default), "open" (fail if the volume does not yet exist) or "new" (fail if the volume already exists).

    Added in version 261.

storage.template=NAME
    The template to use when creating a new volume, if it is missing and the provider supports on-the-fly creation of volumes.

    Added in version 261.

storage.create-size=BYTES
    When creating a new volume on-the-fly, the size in bytes to allocate. Accepts the usual "K"/"M"/"G"/"T" suffixes (base 1024). Required when creating a regular file volume.

    Added in version 261.

EXAMPLES

Example 1. Enumerate available storage providers, volumes and templates

    $ storagectl providers
    $ storagectl volumes
    $ storagectl volumes '*foo*'
    $ storagectl templates

Example 2. Mount a directory volume from the file system provider

    # mount -t storage fs:myvol /mnt/myvol

If the volume "myvol" does not yet exist, it will be created using the default "subvolume" template.

Example 3. Create and mount an ext4 file system from a regular file.

    # mount -t storage.ext4 fs:scratch /mnt/scratch -o loop

Example 4. Mount a block device volume read-only

    # mount -t storage.ext4 -o ro block:/dev/disk/by-id/usb-foo /mnt/foo

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
    Pager to use when --no-pager is not given. $SYSTEMD_PAGER is used if set; otherwise $PAGER is used. If neither $SYSTEMD_PAGER nor $PAGER are set, a set of well-known pager implementations is tried in turn, including less(1) and more(1), until one is found. If no pager implementation is discovered, no pager is invoked. Setting those environment variables to an empty string or the value "cat" is equivalent to passing --no-pager.

    Note: if $SYSTEMD_PAGERSECURE is not set, $SYSTEMD_PAGER and $PAGER can only be used to disable the pager (with "cat" or ""), and are otherwise 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
    Common pager commands like less(1), in addition to "paging", i.e. scrolling through the output, support opening of or writing to other files and running arbitrary shell commands. When commands are invoked with elevated privileges, for example under sudo(8) or pkexec(1), the pager becomes a security boundary. Care must be taken that only programs with strictly limited functionality are used as pagers, and unintended interactive features like opening or creation of new files or starting of subprocesses are not allowed. "Secure mode" for the pager may be enabled as described below, if the pager supports that (most pagers are not written in a way that takes this into consideration). It is recommended to either explicitly enable "secure mode" or to completely disable the pager using --no-pager or PAGER=cat when allowing untrusted users to execute commands with elevated privileges.

    This option takes a boolean argument. When set to true, the "secure mode" of the pager is enabled. In "secure mode", LESSSECURE=1 will be set when invoking the pager, which instructs the pager to disable commands that open or create new files or start new subprocesses. Currently only less(1) is known to understand this variable and implement "secure mode".

    When set to false, no limitation is placed on the pager. Setting SYSTEMD_PAGERSECURE=0 or not removing it from the inherited environment may allow the user to invoke arbitrary commands.

    When $SYSTEMD_PAGERSECURE is not set, systemd tools attempt to automatically figure out if "secure mode" should be enabled and whether the pager supports it. "Secure mode" is enabled if the effective UID is not the same as the owner of the login session, see geteuid(2) and sd_pid_get_owner_uid(3), or when running under sudo(8) or similar tools ($SUDO_UID is set [2]). In those cases, SYSTEMD_PAGERSECURE=1 will be set and pagers which are not known to implement "secure mode" will not be used at all. Note that this autodetection only covers the most common mechanisms to elevate privileges and is intended as convenience. It is recommended to explicitly set $SYSTEMD_PAGERSECURE or disable the pager.

    Note that if the $SYSTEMD_PAGER or $PAGER variables are to be honoured, other than to disable the pager, $SYSTEMD_PAGERSECURE must be set too.

$SYSTEMD_COLORS
    Takes a boolean argument, or a special value. By default (unset), systemd and related utilities will use colors in their output if possible. If $COLORTERM is set to "truecolor" or "24bit", 24-bit colors will be enabled, 256 colors otherwise, unless $NO_COLOR or $TERM indicates colors are disabled.

    true
        Same as unset, except that $NO_COLOR is ignored.

    false
        The output will be monochrome.

    "16", "256", "24bit"
        Always use the base 16 ANSI colors, 256 colors, or 24 bit color, respectively.

    "auto-16", "auto-256", "auto-24bit"
        Use the given quantity of colours, subject to $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.

SEE ALSO

systemd(1), systemd-storage-block@.service(8), systemd-storage-fs@.service(8), varlinkctl(1), mount(8)

NOTES

1.  Varlink
    https://varlink.org/

2.  It is recommended for other tools to set and check $SUDO_UID as appropriate, treating it is a common interface.