systemd-fstab-generator(8)

1SYSTEMD-FSTAB-GENERATOR(8)  systemd-fstab-generator SYSTEMD-FSTAB-GENERATOR(8)
2
3
4

NAME

6       systemd-fstab-generator - Unit generator for /etc/fstab
7

SYNOPSIS

9       /usr/lib/systemd/system-generators/systemd-fstab-generator
10

DESCRIPTION

12       systemd-fstab-generator is a generator that translates /etc/fstab (see
13       fstab(5) for details) into native systemd units early at boot and when
14       configuration of the system manager is reloaded. This will instantiate
15       mount and swap units as necessary.
16
17       The passno field is treated like a simple boolean, and the ordering
18       information is discarded. However, if the root file system is checked,
19       it is checked before all the other file systems.
20
21       See systemd.mount(5) and systemd.swap(5) for more information about
22       special /etc/fstab mount options this generator understands.
23
24       One special topic is handling of symbolic links. Historical init
25       implementations supported symlinks in /etc/fstab. Because mount units
26       will refuse mounts where the target is a symbolic link, this generator
27       will resolve any symlinks as far as possible when processing /etc/fstab
28       in order to enhance backwards compatibility. If a symlink target does
29       not exist at the time that this generator runs, it is assumed that the
30       symlink target is the final target of the mount.
31
32       systemd-fstab-generator implements systemd.generator(7).
33

KERNEL COMMAND LINE

35       systemd-fstab-generator understands the following kernel command line
36       parameters:
37
38       fstab=, rd.fstab=
39           Takes a boolean argument. Defaults to "yes". If "no", causes the
40           generator to ignore any mounts or swap devices configured in
41           /etc/fstab.  rd.fstab= is honored only by the initial RAM disk
42           (initrd) while fstab= is honored by both the main system and the
43           initrd.
44
45       root=
46           Takes the root filesystem to mount in the initrd.  root= is honored
47           by the initrd.
48
49       rootfstype=
50           Takes the root filesystem type that will be passed to the mount
51           command.  rootfstype= is honored by the initrd.
52
53       rootflags=
54           Takes the root filesystem mount options to use.  rootflags= is
55           honored by the initrd.
56
57       mount.usr=
58           Takes the /usr filesystem to be mounted by the initrd. If
59           mount.usrfstype= or mount.usrflags= is set, then mount.usr= will
60           default to the value set in root=.
61
62           Otherwise, this parameter defaults to the /usr entry found in
63           /etc/fstab on the root filesystem.
64
65           mount.usr= is honored by the initrd.
66
67       mount.usrfstype=
68           Takes the /usr filesystem type that will be passed to the mount
69           command. If mount.usr= or mount.usrflags= is set, then
70           mount.usrfstype= will default to the value set in rootfstype=.
71
72           Otherwise, this value will be read from the /usr entry in
73           /etc/fstab on the root filesystem.
74
75           mount.usrfstype= is honored by the initrd.
76
77       mount.usrflags=
78           Takes the /usr filesystem mount options to use. If mount.usr= or
79           mount.usrfstype= is set, then mount.usrflags= will default to the
80           value set in rootflags=.
81
82           Otherwise, this value will be read from the /usr entry in
83           /etc/fstab on the root filesystem.
84
85           mount.usrflags= is honored by the initrd.
86
87       systemd.volatile=
88           Controls whether the system shall boot up in volatile mode. Takes a
89           boolean argument or the special value state.
90
91           If false (the default), this generator makes no changes to the
92           mount tree and the system is booted up in normal mode.
93
94           If true the generator ensures systemd-volatile-root.service(8) is
95           run as part of the initial RAM disk ("initrd"). This service
96           changes the mount table before transitioning to the host system, so
97           that a volatile memory file system ("tmpfs") is used as root
98           directory, with only /usr mounted into it from the configured root
99           file system, in read-only mode. This way the system operates in
100           fully stateless mode, with all configuration and state reset at
101           boot and lost at shutdown, as /etc and /var will be served from the
102           (initially unpopulated) volatile memory file system.
103
104           If set to state the generator will leave the root directory mount
105           point unaltered, however will mount a "tmpfs" file system to /var.
106           In this mode the normal system configuration (i.e. the contents of
107           "/etc") is in effect (and may be modified during system runtime),
108           however the system state (i.e. the contents of "/var") is reset at
109           boot and lost at shutdown.
110
111           Note that in none of these modes the root directory, /etc, /var or
112           any other resources stored in the root file system are physically
113           removed. It's thus safe to boot a system that is normally operated
114           in non-volatile mode temporarily into volatile mode, without losing
115           data.
116
117           Note that enabling this setting will only work correctly on
118           operating systems that can boot up with only /usr mounted, and are
119           able to automatically populate /etc, and also /var in case of
120           "systemd.volatile=yes".
121

NAME

SYNOPSIS

DESCRIPTION

KERNEL COMMAND LINE

SEE ALSO