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NAME | SYNOPSIS | DESCRIPTION | KERNEL COMMAND LINE | SEE ALSO | COLOPHON |
SYSTEMD-FSTAB-GENERATOR(8) systemd-fstab-generatorSYSTEMD-FSTAB-GENERATOR(8)
systemd-fstab-generator - Unit generator for /etc/fstab
/usr/lib/systemd/system-generators/systemd-fstab-generator
systemd-fstab-generator is a generator that translates /etc/fstab
(see fstab(5) for details) into native systemd units early at boot
and when configuration of the system manager is reloaded. This will
instantiate mount and swap units as necessary.
The passno field is treated like a simple boolean, and the ordering
information is discarded. However, if the root file system is
checked, it is checked before all the other file systems.
See systemd.mount(5) and systemd.swap(5) for more information about
special /etc/fstab mount options this generator understands.
systemd-fstab-generator implements systemd.generator(7).
systemd-fstab-generator understands the following kernel command line
parameters:
fstab=, rd.fstab=
Takes a boolean argument. Defaults to "yes". If "no", causes the
generator to ignore any mounts or swap devices configured in
/etc/fstab. rd.fstab= is honored only by the initial RAM disk
(initrd) while fstab= is honored by both the main system and the
initrd.
root=
Takes the root filesystem to mount in the initrd. root= is
honored by the initrd.
rootfstype=
Takes the root filesystem type that will be passed to the mount
command. rootfstype= is honored by the initrd.
rootflags=
Takes the root filesystem mount options to use. rootflags= is
honored by the initrd.
mount.usr=
Takes the /usr filesystem to be mounted by the initrd. If
mount.usrfstype= or mount.usrflags= is set, then mount.usr= will
default to the value set in root=.
Otherwise, this parameter defaults to the /usr entry found in
/etc/fstab on the root filesystem.
mount.usr= is honored by the initrd.
mount.usrfstype=
Takes the /usr filesystem type that will be passed to the mount
command. If mount.usr= or mount.usrflags= is set, then
mount.usrfstype= will default to the value set in rootfstype=.
Otherwise, this value will be read from the /usr entry in
/etc/fstab on the root filesystem.
mount.usrfstype= is honored by the initrd.
mount.usrflags=
Takes the /usr filesystem mount options to use. If mount.usr= or
mount.usrfstype= is set, then mount.usrflags= will default to the
value set in rootflags=.
Otherwise, this value will be read from the /usr entry in
/etc/fstab on the root filesystem.
mount.usrflags= is honored by the initrd.
systemd.volatile=
Controls whether the system shall boot up in volatile mode. Takes
a boolean argument or the special value state.
If false (the default), this generator makes no changes to the
mount tree and the system is booted up in normal mode.
If true the generator ensures systemd-volatile-root.service(8) is
run as part of the initial RAM disk ("initrd"). This service
changes the mount table before transitioning to the host system,
so that a volatile memory file system ("tmpfs") is used as root
directory, with only /usr mounted into it from the configured
root file system, in read-only mode. This way the system operates
in fully stateless mode, with all configuration and state reset
at boot and lost at shutdown, as /etc and /var will be served
from the (initially unpopulated) volatile memory file system.
If set to state the generator will leave the root directory mount
point unaltered, however will mount a "tmpfs" file system to
/var. In this mode the normal system configuration (i.e. the
contents of "/etc") is in effect (and may be modified during
system runtime), however the system state (i.e. the contents of
"/var") is reset at boot and lost at shutdown.
Note that in none of these modes the root directory, /etc, /var
or any other resources stored in the root file system are
physically removed. It's thus safe to boot a system that is
normally operated in non-volatile mode temporarily into volatile
mode, without losing data.
Note that enabling this setting will only work correctly on
operating systems that can boot up with only /usr mounted, and
are able to automatically populate /etc, and also /var in case of
"systemd.volatile=yes".
systemd(1), fstab(5), systemd.mount(5), systemd.swap(5),
systemd-cryptsetup-generator(8), kernel-command-line(7)
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 2017-07-05. If you dis‐
cover 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 234 SYSTEMD-FSTAB-GENERATOR(8)
Pages that refer to this page: systemd.mount(5), systemd.swap(5), kernel-command-line(7), systemd.directives(7), systemd.generator(7), systemd.index(7), systemd.special(7), systemd-gpt-auto-generator(8), systemd-volatile-root.service(8)