systemd-cryptsetup-generator(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | KERNEL COMMAND LINE | SEE ALSO | COLOPHON

SYSTEMD-CRYPTSETUP-GENERATOR(8)ryptsetup-generatorRYPTSETUP-GENERATOR(8)

NAME         top

       systemd-cryptsetup-generator - Unit generator for /etc/crypttab

SYNOPSIS         top

       /usr/lib/systemd/system-generators/systemd-cryptsetup-generator

DESCRIPTION         top

       systemd-cryptsetup-generator is a generator that translates
       /etc/crypttab into native systemd units early at boot and when
       configuration of the system manager is reloaded. This will create
       systemd-cryptsetup@.service(8) units as necessary.

       systemd-cryptsetup-generator implements systemd.generator(7).

KERNEL COMMAND LINE         top

       systemd-cryptsetup-generator understands the following kernel
       command line parameters:

       luks=, rd.luks=
           Takes a boolean argument. Defaults to "yes". If "no",
           disables the generator entirely.  rd.luks= is honored only by
           initial RAM disk (initrd) while luks= is honored by both the
           main system and the initrd.

       luks.crypttab=, rd.luks.crypttab=
           Takes a boolean argument. Defaults to "yes". If "no", causes
           the generator to ignore any devices configured in
           /etc/crypttab (luks.uuid= will still work however).
           rd.luks.crypttab= is honored only by initial RAM disk
           (initrd) while luks.crypttab= is honored by both the main
           system and the initrd.

       luks.uuid=, rd.luks.uuid=
           Takes a LUKS superblock UUID as argument. This will activate
           the specified device as part of the boot process as if it was
           listed in /etc/crypttab. This option may be specified more
           than once in order to set up multiple devices.  rd.luks.uuid=
           is honored only by initial RAM disk (initrd) while luks.uuid=
           is honored by both the main system and the initrd.

           If /etc/crypttab contains entries with the same UUID, then
           the name, keyfile and options specified there will be used.
           Otherwise, the device will have the name "luks-UUID".

           If /etc/crypttab exists, only those UUIDs specified on the
           kernel command line will be activated in the initrd or the
           real root.

       luks.name=, rd.luks.name=
           Takes a LUKS super block UUID followed by an "=" and a name.
           This implies rd.luks.uuid= or luks.uuid= and will
           additionally make the LUKS device given by the UUID appear
           under the provided name.

           This parameter is the analogue of the first crypttab(5) field
           volume-name.

           rd.luks.name= is honored only by initial RAM disk (initrd)
           while luks.name= is honored by both the main system and the
           initrd.

       luks.data=, rd.luks.data=
           Takes a LUKS super block UUID followed by a "=" and a block
           device specification for device hosting encrypted data.

           For those entries specified with rd.luks.uuid= or luks.uuid=,
           the data device will be set to the one specified by
           rd.luks.data= or luks.data= of the corresponding UUID.

           LUKS data device parameter is useful for specifying encrypted
           data devices with detached headers specified in luks.options
           entry containing "header=" argument. For example,
           rd.luks.uuid=b40f1abf-2a53-400a-889a-2eccc27eaa40
           rd.luks.options=b40f1abf-2a53-400a-889a-2eccc27eaa40=header=/path/to/luks.hdr
           rd.luks.data=b40f1abf-2a53-400a-889a-2eccc27eaa40=/dev/sdx.
           Hence, in this case, we will attempt to unlock LUKS device
           assembled from data device "/dev/sdx" and LUKS header
           (metadata) put in "/path/to/luks.hdr" file. This syntax is
           for now only supported on a per-device basis, i.e. you have
           to specify LUKS device UUID.

           This parameter is the analogue of the second crypttab(5)
           field encrypted-device.

           rd.luks.data= is honored only by initial RAM disk (initrd)
           while luks.data= is honored by both the main system and the
           initrd.

       luks.key=, rd.luks.key=
           Takes a password file name as argument or a LUKS super block
           UUID followed by a "=" and a password file name.

           For those entries specified with rd.luks.uuid= or luks.uuid=,
           the password file will be set to the one specified by
           rd.luks.key= or luks.key= of the corresponding UUID, or the
           password file that was specified without a UUID.

           It is also possible to specify an external device which
           should be mounted before we attempt to unlock the LUKS
           device. systemd-cryptsetup will use password file stored on
           that device. Device containing password file is specified by
           appending colon and a device identifier to the password file
           path. For example,
           rd.luks.uuid=b40f1abf-2a53-400a-889a-2eccc27eaa40
           rd.luks.key=b40f1abf-2a53-400a-889a-2eccc27eaa40=/keyfile:LABEL=keydev.
           Hence, in this case, we will attempt to mount file system
           residing on the block device with label "keydev". This syntax
           is for now only supported on a per-device basis, i.e. you
           have to specify LUKS device UUID.

           This parameter is the analogue of the third crypttab(5) field
           key-file.

           rd.luks.key= is honored only by initial RAM disk (initrd)
           while luks.key= is honored by both the main system and the
           initrd.

       luks.options=, rd.luks.options=
           Takes a LUKS super block UUID followed by an "=" and a string
           of options separated by commas as argument. This will
           override the options for the given UUID.

           If only a list of options, without an UUID, is specified,
           they apply to any UUIDs not specified elsewhere, and without
           an entry in /etc/crypttab.

           This parameter is the analogue of the fourth crypttab(5)
           field options.

           It is possible to specify an external device which should be
           mounted before we attempt to unlock the LUKS device.
           systemd-cryptsetup will assemble LUKS device by combining
           data device specified in luks.data with detached LUKS header
           found in "header=" argument. For example,
           rd.luks.uuid=b40f1abf-2a53-400a-889a-2eccc27eaa40
           rd.luks.options=b40f1abf-2a53-400a-889a-2eccc27eaa40=header=/luks.hdr:LABEL=hdrdev
           rd.luks.data=b40f1abf-2a53-400a-889a-2eccc27eaa40=/dev/sdx.
           Hence, in this case, we will attempt to mount file system
           residing on the block device with label "hdrdev", and look
           for "luks.hdr" on that file system. Said header will be used
           to unlock (decrypt) encrypted data stored on /dev/sdx. This
           syntax is for now only supported on a per-device basis, i.e.
           you have to specify LUKS device UUID.

           rd.luks.options= is honored only by initial RAM disk (initrd)
           while luks.options= is honored by both the main system and
           the initrd.

SEE ALSO         top

       systemd(1), crypttab(5), systemd-cryptsetup@.service(8),
       systemd-cryptenroll(1), cryptsetup(8), systemd-fstab-generator(8)

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have
       a bug report for this manual page, see
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
       This page was obtained from the project's upstream Git repository
       ⟨https://github.com/systemd/systemd.git⟩ on 2021-08-27.  (At that
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systemd 249                              SYSTEMD-CRYPTSETUP-GENERATOR(8)

Pages that refer to this page: crypttab(5)kernel-command-line(7)systemd.generator(7)systemd-cryptsetup@.service(8)systemd-fstab-generator(8)