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NAME | SYNOPSIS | DESCRIPTION | KERNEL COMMAND LINE | SEE ALSO | COLOPHON |
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SYSTEMD...NERATOR(8) systemd-cryptsetup-generator SYSTEMD...NERATOR(8)
systemd-cryptsetup-generator - Unit generator for /etc/crypttab
/usr/lib/systemd/system-generators/systemd-cryptsetup-generator
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).
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 in
the initrd while luks= is honored by both the main system and
in the initrd.
Added in version 186.
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 in initrd while
luks.crypttab= is honored by both the main system and in the
initrd.
Added in version 186.
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 in the initrd, while luks.uuid= is honored by
both the main system and in 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.
Added in version 186.
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 in the initrd, while luks.name=
is honored by both the main system and in the initrd.
Added in version 218.
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 in the initrd, while luks.data=
is honored by both the main system and in the initrd.
Added in version 247.
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 in the initrd, while luks.key=
is honored by both the main system and in the initrd.
Added in version 202.
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 a 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 in
the initrd.
Added in version 208.
systemd(1), crypttab(5), systemd-cryptsetup@.service(8),
systemd-cryptenroll(1), cryptsetup(8), systemd-fstab-generator(8)
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 2024-06-14. (At that
time, the date of the most recent commit that was found in the
repository was 2024-06-13.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
systemd 257~devel SYSTEMD...NERATOR(8)
Pages that refer to this page: crypttab(5), kernel-command-line(7), systemd.directives(7), systemd.generator(7), systemd.index(7), systemd-cryptsetup(8), systemd-fstab-generator(8)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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