From b750101eb236130cf056c675997decbac904cc49 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 17:35:18 +0200 Subject: Adding upstream version 252.22. Signed-off-by: Daniel Baumann --- man/systemd-fstab-generator.xml | 255 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 255 insertions(+) create mode 100644 man/systemd-fstab-generator.xml (limited to 'man/systemd-fstab-generator.xml') diff --git a/man/systemd-fstab-generator.xml b/man/systemd-fstab-generator.xml new file mode 100644 index 0000000..29d9bd4 --- /dev/null +++ b/man/systemd-fstab-generator.xml @@ -0,0 +1,255 @@ + + + + + + + + systemd-fstab-generator + systemd + + + + systemd-fstab-generator + 8 + + + + systemd-fstab-generator + Unit generator for /etc/fstab + + + + /usr/lib/systemd/system-generators/systemd-fstab-generator + + + + Description + + systemd-fstab-generator is a generator + that translates /etc/fstab (see + fstab5 + 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.mount5 + and + systemd.swap5 + for more information about special /etc/fstab + mount options this generator understands. + + One special topic is handling of symbolic links. Historical init + implementations supported symlinks in /etc/fstab. + Because mount units will refuse mounts where the target is a symbolic link, + this generator will resolve any symlinks as far as possible when processing + /etc/fstab in order to enhance backwards compatibility. + If a symlink target does not exist at the time that this generator runs, it + is assumed that the symlink target is the final target of the mount. + + systemd-fstab-generator implements + systemd.generator7. + + + + Kernel Command Line + + 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 in the initrd, while + fstab= is honored by both the main system and the initrd. + + + + root= + + Configures the operating system's root filesystem to mount when running in the + initrd. This accepts a device node path (usually /dev/disk/by-uuid/… or + /dev/disk/by-label/… or similar), or the special values gpt-auto + and tmpfs. + + Use gpt-auto to explicitly request automatic root file system discovery via + systemd-gpt-auto-generator8. + + Use tmpfs in order to mount a tmpfs5 file + system as root file system of the OS. This is useful in combination with + mount.usr= (see below) in order to combine a volatile root file system with a + separate, immutable /usr/ file system. Also see + systemd.volatile= below. + + + + 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. + + Note that unlike most kernel command line options this setting does not override settings made + in configuration files (specifically: the mount option string in + /etc/fstab). See + systemd-remount-fs.service8. + + + + 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. + + + + roothash= + usrhash= + + These options are primarily read by + systemd-veritysetup-generator8. When + set this indicates that the root file system (or /usr/) shall be mounted from + Verity volumes with the specified hashes. If these kernel command line options are set the root (or + /usr/) file system is thus mounted from a device mapper volume + /dev/mapper/root (or /dev/mapper/usr). + + + + systemd.volatile= + + Controls whether the system shall boot up in volatile mode. Takes a boolean argument or the + special value . + + 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.service8 + is run in the 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 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. + + If this setting is set to overlay the root file system is set up as + overlayfs mount combining the read-only root directory with a writable + tmpfs, so that no modifications are made to disk, but the file system may be modified + nonetheless with all changes being lost at reboot. + + 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 with the exception of overlay mode, 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. + + Also see root=tmpfs above, for a method to combine a + tmpfs file system with a regular /usr/ file system (as + configured via mount.usr=). The main distinction between + systemd.volatile=yes, and root=tmpfs in combination + mount.usr= is that the former operates on top of a regular root file system and + temporarily obstructs the files and directories above its /usr/ subdirectory, + while the latter does not hide any files, but simply mounts a unpopulated tmpfs as root file system + and combines it with a user picked /usr/ file system. + + + + systemd.swap= + + Takes a boolean argument or enables the option if specified + without an argument. If disabled, causes the generator to ignore + any swap devices configured in /etc/fstab. + Defaults to enabled. + + + + + + See Also + + systemd1, + fstab5, + systemd.mount5, + systemd.swap5, + systemd-cryptsetup-generator8, + systemd-gpt-auto-generator8, + kernel-command-line7, + Known Environment Variables + + + -- cgit v1.2.3