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.
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.
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.
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.
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.
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.
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.