]> git.ipfire.org Git - thirdparty/systemd.git/blobdiff - man/crypttab.xml
test-execute: change log level from error to notice
[thirdparty/systemd.git] / man / crypttab.xml
index d61ec95e4cbaedc49b6f3b3cce760e51d63fca06..dc43257d4ed4336077fa2d5ad9b94bafbd9e703a 100644 (file)
@@ -2,6 +2,8 @@
 <!--*-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+
+
   This file is part of systemd.
 
   Copyright 2012 Lennart Poettering
   The Red Hat version has been written by Miloslav Trmac <mitr@redhat.com>.
 
 -->
-<refentry id="crypttab">
-
-        <refentryinfo>
-                <title>crypttab</title>
-                <productname>systemd</productname>
-
-                <authorgroup>
-                        <author>
-                                <contrib>Documentation</contrib>
-                                <firstname>Miloslav</firstname>
-                                <surname>Trmac</surname>
-                                <email>mitr@redhat.com</email>
-                        </author>
-                        <author>
-                                <contrib>Documentation</contrib>
-                                <firstname>Lennart</firstname>
-                                <surname>Poettering</surname>
-                                <email>lennart@poettering.net</email>
-                        </author>
-                </authorgroup>
-        </refentryinfo>
-
-        <refmeta>
-                <refentrytitle>crypttab</refentrytitle>
-                <manvolnum>5</manvolnum>
-        </refmeta>
-
-        <refnamediv>
-                <refname>crypttab</refname>
-                <refpurpose>Configuration for encrypted block devices</refpurpose>
-        </refnamediv>
-
-        <refsynopsisdiv>
-                <para><filename>/etc/crypttab</filename></para>
-        </refsynopsisdiv>
-
-        <refsect1>
-                <title>Description</title>
-
-                <para>The <filename>/etc/crypttab</filename> file
-                describes encrypted block devices that are set up
-                during system boot.</para>
-
-                <para>Empty lines and lines starting with the #
-                character are ignored.  Each of the remaining lines
-                describes one encrypted block device, fields on the
-                line are delimited by white space.  The first two
-                fields are mandatory, the remaining two are
-                optional.</para>
-
-                <para>The first field contains the name of the
-                resulting encrypted block device; the device is set up
-                within <filename>/dev/mapper/</filename>.</para>
-
-                <para>The second field contains a path to the
-                underlying block device, or a specification of a block
-                device via <literal>UUID=</literal> followed by the
-                UUID.  If the block device contains a LUKS signature,
-                it is opened as a LUKS encrypted partition; otherwise
-                it is assumed to be a raw dm-crypt partition.</para>
-
-                <para>The third field specifies the encryption
-                password.  If the field is not present or the password
-                is set to none, the password has to be manually
-                entered during system boot.  Otherwise the field is
-                interpreted as a path to a file containing the
-                encryption password.  For swap encryption
-                <filename>/dev/urandom</filename> or the hardware
-                device <filename>/dev/hw_random</filename> can be used
-                as the password file; using
-                <filename>/dev/random</filename> may prevent boot
-                completion if the system does not have enough entropy
-                to generate a truly random encryption key.</para>
-
-                <para>The fourth field, if present, is a
-                comma-delimited list of options.  The following
-                options are recognized:</para>
-
-                <variablelist>
-                        <varlistentry>
-                                <term><varname>cipher=</varname></term>
-
-                                <listitem><para>Specifies the cipher
-                                to use; see
-                                <citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
-                                for possible values and the default
-                                value of this option.  A cipher with
-                                unpredictable IV values, such as
-                                <literal>aes-cbc-essiv:sha256</literal>,
-                                is recommended. </para></listitem>
-                        </varlistentry>
-
-
-                        <varlistentry>
-                                <term><varname>size=</varname></term>
-
-                                <listitem><para>Specifies the key size
-                                in bits; see
-                                <citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
-                                for possible values and the default
-                                value of this
-                                option. </para></listitem>
-                        </varlistentry>
-
-
-                        <varlistentry>
-                                <term><varname>hash=</varname></term>
-
-                                <listitem><para>Specifies the hash to
-                                use for password hashing; see
-                                <citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry> for possible values and
-                                the default value of this
-                                option. </para></listitem>
-                        </varlistentry>
-
-                        <varlistentry>
-                                <term><varname>tries=</varname></term>
-
-                                <listitem><para>Specifies the maximum
-                                number of times the user is queried
-                                for a password.</para></listitem>
-                        </varlistentry>
-
-                        <varlistentry>
-                                <term><varname>verify</varname></term>
-
-                                <listitem><para> If the the encryption
-                                password is read from console, it has
-                                to be entered twice (to prevent
-                                typos). </para></listitem>
-                        </varlistentry>
-
-                        <varlistentry>
-                                <term><varname>read-only</varname></term>
-
-                                <listitem><para>Set up the encrypted
-                                block device in read-only
-                                mode.</para></listitem>
-                        </varlistentry>
-
-                        <varlistentry>
-                                <term><varname>allow-discards</varname></term>
-
-                                <listitem><para>Allow discard requests
-                                to be passed through the encrypted
-                                block device. This improves
-                                performance on SSD storage but has
-                                security
-                                implications.</para></listitem>
-                        </varlistentry>
-
-                        <varlistentry>
-                                <term><varname>luks</varname></term>
-
-                                <listitem><para>Force LUKS mode.</para></listitem>
-                        </varlistentry>
-
-                        <varlistentry>
-                                <term><varname>plain</varname></term>
-
-                                <listitem><para>Force plain encryption
-                                mode.</para></listitem>
-                        </varlistentry>
-
-                        <varlistentry>
-                                <term><varname>timeout=</varname></term>
-
-                                <listitem><para>Specify the timeout
-                                for querying for a password. If not
-                                unit is specified in
-                                seconds. Supported units are s, ms,
-                                us, min, h, d.</para></listitem>
-                        </varlistentry>
-
-                        <varlistentry>
-                                <term><varname>noauto</varname></term>
-
-                                <listitem><para> This device will not
-                                be automatically unlocked on
-                                boot. </para></listitem>
-                        </varlistentry>
-
-                        <varlistentry>
-                                <term><varname>nofail</varname></term>
-
-                                <listitem><para>The system will not
-                                wait for the device to show up and be
-                                unlocked at boot, and not fail the
-                                boot if it doesn't show
-                                up.</para></listitem>
-                        </varlistentry>
-
-                        <varlistentry>
-                                <term><varname>swap</varname></term>
-
-                                <listitem><para> The encrypted block
-                                device will be used as a swap
-                                partition, and will be formatted as a
-                                swap partition after setting up the
-                                encrypted block device, with
-                                <citerefentry><refentrytitle>mkswap</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
-
-                                <para>WARNING: Using the
-                                <varname>swap</varname> option will
-                                destroy the contents of the named
-                                partition during every boot, so make
-                                sure the underlying block device is
-                                specified
-                                correctly. </para></listitem>
-                        </varlistentry>
-
-                        <varlistentry>
-                                <term><varname>tmp</varname></term>
-
-                                <listitem><para>The encrypted block
-                                device will be prepared for using it
-                                as <filename>/tmp</filename>
-                                partition: it will be formatted using
-                                <citerefentry><refentrytitle>mke2fs</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
-
-                                <para>WARNING: Using the
-                                <varname>tmp</varname> option will
-                                destroy the contents of the named
-                                partition during every boot, so make
-                                sure the underlying block device is
-                                specified
-                                correctly. </para></listitem>
-                        </varlistentry>
-                </variablelist>
-
-        </refsect1>
-
-        <refsect1>
-                <title>Example</title>
-                <example>
-                        <title>/etc/crypttab example</title>
-                        <para>Set up two encrypted block devices with
-                        LUKS: one normal one for storage, and another
-                        one for usage as swap device.</para>
-
-                        <programlisting>luks-2505567a-9e27-4efe-a4d5-15ad146c258b UUID=2505567a-9e27-4efe-a4d5-15ad146c258b - timeout=0
-swap /dev/sda7 /dev/urandom swap</programlisting>
-                </example>
-        </refsect1>
-
-        <refsect1>
-                <title>See Also</title>
-                <para>
-                        <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
-                        <citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
-                        <citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
-                        <citerefentry><refentrytitle>mkswap</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
-                        <citerefentry><refentrytitle>mke2fs</refentrytitle><manvolnum>8</manvolnum></citerefentry>
-                </para>
-        </refsect1>
+<refentry id="crypttab" conditional='HAVE_LIBCRYPTSETUP'>
+
+  <refentryinfo>
+    <title>crypttab</title>
+    <productname>systemd</productname>
+
+    <authorgroup>
+      <author>
+        <contrib>Documentation</contrib>
+        <firstname>Miloslav</firstname>
+        <surname>Trmac</surname>
+        <email>mitr@redhat.com</email>
+      </author>
+      <author>
+        <contrib>Documentation</contrib>
+        <firstname>Lennart</firstname>
+        <surname>Poettering</surname>
+        <email>lennart@poettering.net</email>
+      </author>
+    </authorgroup>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>crypttab</refentrytitle>
+    <manvolnum>5</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>crypttab</refname>
+    <refpurpose>Configuration for encrypted block devices</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <para><filename>/etc/crypttab</filename></para>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Description</title>
+
+    <para>The <filename>/etc/crypttab</filename> file describes
+    encrypted block devices that are set up during system boot.</para>
+
+    <para>Empty lines and lines starting with the <literal>#</literal>
+    character are ignored. Each of the remaining lines describes one
+    encrypted block device. Fields are delimited by white space.</para>
+
+    <para>Each line is in the form<programlisting><replaceable>name</replaceable> <replaceable>encrypted-device</replaceable> <replaceable>password</replaceable> <replaceable>options</replaceable></programlisting>
+    The first two fields are mandatory, the remaining two are
+    optional.</para>
+
+    <para>Setting up encrypted block devices using this file supports
+    three encryption modes: LUKS, TrueCrypt and plain. See
+    <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+    for more information about each mode. When no mode is specified in
+    the options field and the block device contains a LUKS signature,
+    it is opened as a LUKS device; otherwise, it is assumed to be in
+    raw dm-crypt (plain mode) format.</para>
+
+    <para>The first field contains the name of the resulting encrypted
+    block device; the device is set up within
+    <filename>/dev/mapper/</filename>.</para>
+
+    <para>The second field contains a path to the underlying block
+    device or file, or a specification of a block device via
+    <literal>UUID=</literal> followed by the UUID.</para>
+
+    <para>The third field specifies the encryption password. If the
+    field is not present or the password is set to
+    <literal>none</literal> or <literal>-</literal>, the password has
+    to be manually entered during system boot. Otherwise, the field is
+    interpreted as an absolute path to a file containing the encryption
+    password. For swap encryption, <filename>/dev/urandom</filename>
+    or the hardware device <filename>/dev/hw_random</filename> can be
+    used as the password file; using <filename>/dev/random</filename>
+    may prevent boot completion if the system does not have enough
+    entropy to generate a truly random encryption key.</para>
+
+    <para>The fourth field, if present, is a comma-delimited list of
+    options. The following options are recognized:</para>
+
+    <variablelist class='fstab-options'>
+
+      <varlistentry>
+        <term><option>cipher=</option></term>
+
+        <listitem><para>Specifies the cipher to use. See
+        <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+        for possible values and the default value of this option. A
+        cipher with unpredictable IV values, such as
+        <literal>aes-cbc-essiv:sha256</literal>, is
+        recommended.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>discard</option></term>
+
+        <listitem><para>Allow discard requests to be passed through the encrypted block
+        device. This improves performance on SSD storage but has security implications.
+        </para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>hash=</option></term>
+
+        <listitem><para>Specifies the hash to use for password
+        hashing. See
+        <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+        for possible values and the default value of this
+        option.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>header=</option></term>
+
+        <listitem><para>Use a detached (separated) metadata device or
+        file where the LUKS header is stored. This option is only
+        relevant for LUKS devices. See
+        <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+        for possible values and the default value of this
+        option.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>keyfile-offset=</option></term>
+
+        <listitem><para>Specifies the number of bytes to skip at the
+        start of the key file. See
+        <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+        for possible values and the default value of this
+        option.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>keyfile-size=</option></term>
+
+        <listitem><para>Specifies the maximum number of bytes to read
+        from the key file. See
+        <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+        for possible values and the default value of this option. This
+        option is ignored in plain encryption mode, as the key file
+        size is then given by the key size.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>key-slot=</option></term>
+
+        <listitem><para>Specifies the key slot to compare the
+        passphrase or key against. If the key slot does not match the
+        given passphrase or key, but another would, the setup of the
+        device will fail regardless. This option implies
+        <option>luks</option>. See
+        <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+        for possible values. The default is to try all key slots in
+        sequential order.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>luks</option></term>
+
+        <listitem><para>Force LUKS mode. When this mode is used, the
+        following options are ignored since they are provided by the
+        LUKS header on the device: <option>cipher=</option>,
+        <option>hash=</option>,
+        <option>size=</option>.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>_netdev</option></term>
+
+        <listitem><para>Marks this cryptsetup device as requiring network. It will be
+        started after the network is available, similarly to
+        <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+        units marked with <option>_netdev</option>. The service unit to set up this device
+        will be ordered between <filename>remote-fs-pre.target</filename> and
+        <filename>remote-cryptsetup.target</filename>, instead of
+        <filename>cryptsetup-pre.target</filename> and
+        <filename>cryptsetup.target</filename>.</para>
+
+        <para>Hint: if this device is used for a mount point that is specified in
+        <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+        the <option>_netdev</option> option should also be used for the mount
+        point. Otherwise, a dependency loop might be created where the mount point
+        will be pulled in by <filename>local-fs.target</filename>, while the
+        service to configure the network is usually only started <emphasis>after</emphasis>
+        the local file system has been mounted.</para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>noauto</option></term>
+
+        <listitem><para>This device will not be added to <filename>cryptsetup.target</filename>.
+        This means that it will not be automatically unlocked on boot, unless something else pulls
+        it in. In particular, if the device is used for a mount point, it'll be unlocked
+        automatically during boot, unless the mount point itself is also disabled with
+        <option>noauto</option>.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>nofail</option></term>
+
+        <listitem><para>This device will not be a hard dependency of
+        <filename>cryptsetup.target</filename>. It'll be still pulled in and started, but the system
+        will not wait for the device to show up and be unlocked, and boot will not fail if this is
+        unsuccessful. Note that other units that depend on the unlocked device may still fail. In
+        particular, if the device is used for a mount point, the mount point itself is also needs to
+        have <option>noauto</option> option, or the boot will fail if the device is not unlocked
+        successfully.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>offset=</option></term>
+
+        <listitem><para>Start offset in the backend device, in 512-byte sectors. This
+        option is only relevant for plain devices.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>plain</option></term>
+
+        <listitem><para>Force plain encryption mode.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>read-only</option></term><term><option>readonly</option></term>
+
+        <listitem><para>Set up the encrypted block device in read-only
+        mode.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>skip=</option></term>
+
+        <listitem><para>How many 512-byte sectors of the encrypted data to skip at the
+        beginning. This is different from the <option>offset=</option> option with respect
+        to the sector numbers used in initialization vector (IV) calculation. Using
+        <option>offset=</option> will shift the IV calculation by the same negative
+        amount. Hence, if <option>offset=<replaceable>n</replaceable></option> is given,
+        sector <replaceable>n</replaceable> will get a sector number of 0 for the IV
+        calculation. Using <option>skip=</option> causes sector
+        <replaceable>n</replaceable> to also be the first sector of the mapped device, but
+        with its number for IV generation being <replaceable>n</replaceable>.</para>
+
+        <para>This option is only relevant for plain devices.</para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>size=</option></term>
+
+        <listitem><para>Specifies the key size in bits. See
+        <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+        for possible values and the default value of this
+        option.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>swap</option></term>
+
+        <listitem><para>The encrypted block device will be used as a
+        swap device, and will be formatted accordingly after setting
+        up the encrypted block device, with
+        <citerefentry project='man-pages'><refentrytitle>mkswap</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
+        This option implies <option>plain</option>.</para>
+
+        <para>WARNING: Using the <option>swap</option> option will
+        destroy the contents of the named partition during every boot,
+        so make sure the underlying block device is specified
+        correctly.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>tcrypt</option></term>
+
+        <listitem><para>Use TrueCrypt encryption mode. When this mode
+        is used, the following options are ignored since they are
+        provided by the TrueCrypt header on the device or do not
+        apply:
+        <option>cipher=</option>,
+        <option>hash=</option>,
+        <option>keyfile-offset=</option>,
+        <option>keyfile-size=</option>,
+        <option>size=</option>.</para>
+
+        <para>When this mode is used, the passphrase is read from the
+        key file given in the third field. Only the first line of this
+        file is read, excluding the new line character.</para>
+
+        <para>Note that the TrueCrypt format uses both passphrase and
+        key files to derive a password for the volume. Therefore, the
+        passphrase and all key files need to be provided. Use
+        <option>tcrypt-keyfile=</option> to provide the absolute path
+        to all key files. When using an empty passphrase in
+        combination with one or more key files, use
+        <literal>/dev/null</literal> as the password file in the third
+        field.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>tcrypt-hidden</option></term>
+
+        <listitem><para>Use the hidden TrueCrypt volume. This option
+        implies <option>tcrypt</option>.</para>
+
+        <para>This will map the hidden volume that is inside of the
+        volume provided in the second field. Please note that there is
+        no protection for the hidden volume if the outer volume is
+        mounted instead. See
+        <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+        for more information on this limitation.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>tcrypt-keyfile=</option></term>
+
+        <listitem><para>Specifies the absolute path to a key file to
+        use for a TrueCrypt volume. This implies
+        <option>tcrypt</option> and can be used more than once to
+        provide several key files.</para>
+
+        <para>See the entry for <option>tcrypt</option> on the
+        behavior of the passphrase and key files when using TrueCrypt
+        encryption mode.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>tcrypt-system</option></term>
+
+        <listitem><para>Use TrueCrypt in system encryption mode. This
+        option implies <option>tcrypt</option>.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>tcrypt-veracrypt</option></term>
+
+        <listitem><para>Check for a VeraCrypt volume.  VeraCrypt is a fork of
+        TrueCrypt that is mostly compatible, but uses different, stronger key
+        derivation algorithms that cannot be detected without this flag.
+        Enabling this option could substantially slow down unlocking, because
+        VeraCrypt's key derivation takes much longer than TrueCrypt's.  This
+        option implies <option>tcrypt</option>.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>timeout=</option></term>
+
+        <listitem><para>Specifies the timeout for querying for a
+        password. If no unit is specified, seconds is used. Supported
+        units are s, ms, us, min, h, d. A timeout of 0 waits
+        indefinitely (which is the default).</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>tmp</option></term>
+
+        <listitem><para>The encrypted block device will be prepared
+        for using it as <filename>/tmp</filename>; it will be
+        formatted using
+        <citerefentry project='man-pages'><refentrytitle>mke2fs</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
+        This option implies <option>plain</option>.</para>
+
+        <para>WARNING: Using the <option>tmp</option> option will
+        destroy the contents of the named partition during every boot,
+        so make sure the underlying block device is specified
+        correctly.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>tries=</option></term>
+
+        <listitem><para>Specifies the maximum number of times the user
+        is queried for a password. The default is 3. If set to 0, the
+        user is queried for a password indefinitely.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>verify</option></term>
+
+        <listitem><para> If the encryption password is read from
+        console, it has to be entered twice to prevent
+        typos.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>x-systemd.device-timeout=</option></term>
+
+        <listitem><para>Specifies how long systemd should wait for a device to show up
+        before giving up on the entry. The argument is a time in seconds or explicitly
+        specified units of
+        <literal>s</literal>,
+        <literal>min</literal>,
+        <literal>h</literal>,
+        <literal>ms</literal>.
+        </para></listitem>
+      </varlistentry>
+
+    </variablelist>
+
+    <para>At early boot and when the system manager configuration is
+    reloaded, this file is translated into native systemd units by
+    <citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Example</title>
+    <example>
+      <title>/etc/crypttab example</title>
+      <para>Set up four encrypted block devices. One using LUKS for
+      normal storage, another one for usage as a swap device and two
+      TrueCrypt volumes.</para>
+
+      <programlisting>luks       UUID=2505567a-9e27-4efe-a4d5-15ad146c258b
+swap       /dev/sda7       /dev/urandom       swap
+truecrypt  /dev/sda2       /etc/container_password  tcrypt
+hidden     /mnt/tc_hidden  /dev/null    tcrypt-hidden,tcrypt-keyfile=/etc/keyfile</programlisting>
+    </example>
+  </refsect1>
+
+  <refsect1>
+    <title>See Also</title>
+    <para>
+      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+      <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+      <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+      <citerefentry project='man-pages'><refentrytitle>mkswap</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+      <citerefentry project='man-pages'><refentrytitle>mke2fs</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+    </para>
+  </refsect1>
 
 </refentry>