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diff --git a/man/systemd-fstab-generator.xml b/man/systemd-fstab-generator.xml new file mode 100644 index 0000000..ab70642 --- /dev/null +++ b/man/systemd-fstab-generator.xml @@ -0,0 +1,207 @@ +<?xml version="1.0"?> +<!--*-nxml-*--> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> +<!-- + SPDX-License-Identifier: LGPL-2.1+ +--> +<refentry id="systemd-fstab-generator"> + + <refentryinfo> + <title>systemd-fstab-generator</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>systemd-fstab-generator</refentrytitle> + <manvolnum>8</manvolnum> + </refmeta> + + <refnamediv> + <refname>systemd-fstab-generator</refname> + <refpurpose>Unit generator for /etc/fstab</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <para><filename>/usr/lib/systemd/system-generators/systemd-fstab-generator</filename></para> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><filename>systemd-fstab-generator</filename> is a generator + that translates <filename>/etc/fstab</filename> (see + <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry> + 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.</para> + + <para>The <varname>passno</varname> 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.</para> + + <para>See + <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry> + and + <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for more information about special <filename>/etc/fstab</filename> + mount options this generator understands.</para> + + <para>One special topic is handling of symbolic links. Historical init + implementations supported symlinks in <filename>/etc/fstab</filename>. + 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 + <filename>/etc/fstab</filename> 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.</para> + + <para><filename>systemd-fstab-generator</filename> implements + <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> + </refsect1> + + <refsect1> + <title>Kernel Command Line</title> + + <para><filename>systemd-fstab-generator</filename> understands the + following kernel command line parameters:</para> + + <variablelist class='kernel-commandline-options'> + + <varlistentry> + <term><varname>fstab=</varname></term> + <term><varname>rd.fstab=</varname></term> + + <listitem><para>Takes a boolean argument. Defaults to + <literal>yes</literal>. If <literal>no</literal>, causes the + generator to ignore any mounts or swap devices configured in + <filename>/etc/fstab</filename>. <varname>rd.fstab=</varname> + is honored only by the initial RAM disk (initrd) while + <varname>fstab=</varname> is honored by both the main system + and the initrd.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>root=</varname></term> + + <listitem><para>Takes the root filesystem to mount in the + initrd. <varname>root=</varname> is honored by the + initrd.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>rootfstype=</varname></term> + + <listitem><para>Takes the root filesystem type that will be + passed to the mount command. <varname>rootfstype=</varname> is + honored by the initrd.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>rootflags=</varname></term> + + <listitem><para>Takes the root filesystem mount options to + use. <varname>rootflags=</varname> is honored by the + initrd.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>mount.usr=</varname></term> + + <listitem><para>Takes the <filename>/usr</filename> filesystem + to be mounted by the initrd. If + <varname>mount.usrfstype=</varname> or + <varname>mount.usrflags=</varname> is set, then + <varname>mount.usr=</varname> will default to the value set in + <varname>root=</varname>.</para> + + <para>Otherwise, this parameter defaults to the + <filename>/usr</filename> entry found in + <filename>/etc/fstab</filename> on the root filesystem.</para> + + <para><varname>mount.usr=</varname> is honored by the initrd. + </para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>mount.usrfstype=</varname></term> + + <listitem><para>Takes the <filename>/usr</filename> filesystem + type that will be passed to the mount command. If + <varname>mount.usr=</varname> or + <varname>mount.usrflags=</varname> is set, then + <varname>mount.usrfstype=</varname> will default to the value + set in <varname>rootfstype=</varname>.</para> + + <para>Otherwise, this value will be read from the + <filename>/usr</filename> entry in + <filename>/etc/fstab</filename> on the root filesystem.</para> + + <para><varname>mount.usrfstype=</varname> is honored by the + initrd.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>mount.usrflags=</varname></term> + + <listitem><para>Takes the <filename>/usr</filename> filesystem + mount options to use. If <varname>mount.usr=</varname> or + <varname>mount.usrfstype=</varname> is set, then + <varname>mount.usrflags=</varname> will default to the value + set in <varname>rootflags=</varname>.</para> + + <para>Otherwise, this value will be read from the + <filename>/usr</filename> entry in + <filename>/etc/fstab</filename> on the root filesystem.</para> + + <para><varname>mount.usrflags=</varname> is honored by the + initrd.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>systemd.volatile=</varname></term> + + <listitem><para>Controls whether the system shall boot up in volatile mode. Takes a boolean argument or the + special value <option>state</option>.</para> + + <para>If false (the default), this generator makes no changes to the mount tree and the system is booted up in + normal mode.</para> + + <para>If true the generator ensures + <citerefentry><refentrytitle>systemd-volatile-root.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + 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 (<literal>tmpfs</literal>) is used as root directory, + with only <filename>/usr</filename> 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 <filename>/etc</filename> and <filename>/var</filename> will be served from the (initially + unpopulated) volatile memory file system.</para> + + <para>If set to <option>state</option> the generator will leave the root + directory mount point unaltered, however will mount a <literal>tmpfs</literal> file system to + <filename>/var</filename>. In this mode the normal system configuration (i.e. the contents of + <literal>/etc</literal>) is in effect (and may be modified during system runtime), however the system state + (i.e. the contents of <literal>/var</literal>) is reset at boot and lost at shutdown.</para> + + <para>Note that in none of these modes the root directory, <filename>/etc</filename>, <filename>/var</filename> + 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.</para> + + <para>Note that enabling this setting will only work correctly on operating systems that can boot up with only + <filename>/usr</filename> mounted, and are able to automatically populate <filename>/etc</filename>, and also + <filename>/var</filename> in case of <literal>systemd.volatile=yes</literal>.</para></listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>See Also</title> + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |