man/systemd-gpt-auto-generator.xml

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  22 <refentry id="systemd-gpt-auto-generator">
  23
  24   <refentryinfo>
  25     <title>systemd-gpt-auto-generator</title>
  26     <productname>systemd</productname>
  27
  28     <authorgroup>
  29       <author>
  30         <contrib>Developer</contrib>
  31         <firstname>Lennart</firstname>
  32         <surname>Poettering</surname>
  33         <email>lennart@poettering.net</email>
  34       </author>
  35     </authorgroup>
  36   </refentryinfo>
  37
  38   <refmeta>
  39     <refentrytitle>systemd-gpt-auto-generator</refentrytitle>
  40     <manvolnum>8</manvolnum>
  41   </refmeta>
  42
  43   <refnamediv>
  44     <refname>systemd-gpt-auto-generator</refname>
  45     <refpurpose>Generator for automatically discovering
  46     and mounting root, <filename>/home</filename> and
  47     <filename>/srv</filename> partitions, as well as
  48     discovering and enabling swap partitions, based on GPT
  49     partition type GUIDs.</refpurpose>
  50   </refnamediv>
  51
  52   <refsynopsisdiv>
  53     <para><filename>/usr/lib/systemd/system-generators/systemd-gpt-auto-generator</filename></para>
  54   </refsynopsisdiv>
  55
  56   <refsect1>
  57     <title>Description</title>
  58
  59     <para><filename>systemd-gpt-auto-generator</filename> is a unit
  60     generator that automatically discovers root,
  61     <filename>/home</filename>, <filename>/srv</filename> and swap
  62     partitions and creates mount and swap units for them, based on the
  63     partition type GUIDs of GUID partition tables (GPT). It implements
  64     the <ulink
  65     url="http://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/">Discoverable
  66     Partitions Specification</ulink>. Note that this generator has no
  67     effect on non-GPT systems, or where the directories under the
  68     mount points are already non-empty. Also, on systems where the
  69     units are explicitly configured (for example, listed in
  70     <citerefentry
  71     project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>),
  72     the units this generator creates are overridden, but additional
  73     automatic dependencies might be created.</para>
  74
  75     <para>This generator will only look for root partitions on the
  76     same physical disk the EFI System Partition (ESP) is located on.
  77     It will only look for the other partitions on the same physical
  78     disk the root file system is located on. These partitions will not
  79     be searched on systems where the root file system is distributed
  80     on multiple disks, for example via btrfs RAID.</para>
  81
  82     <para><filename>systemd-gpt-auto-generator</filename> is useful
  83     for centralizing file system configuration in the partition table
  84     and making manual configuration in <filename>/etc/fstab</filename>
  85     or suchlike unnecessary.</para>
  86
  87     <para>This generator looks for the partitions based on their
  88     partition type GUID. The following partition type GUIDs are
  89     identified:</para>
  90
  91     <table>
  92       <title>Partition Type GUIDs</title>
  93       <tgroup cols='3' align='left' colsep='1' rowsep='1'>
  94         <colspec colname="guid" />
  95         <colspec colname="name" />
  96         <colspec colname="explanation" />
  97         <thead>
  98           <row>
  99             <entry>Partition Type GUID</entry>
 100             <entry>Name</entry>
 101             <entry>Explanation</entry>
 102           </row>
 103         </thead>
 104         <tbody>
 105           <row>
 106             <entry>44479540-f297-41b2-9af7-d131d5f0458a</entry>
 107             <entry><filename>Root Partition (x86)</filename></entry>
 108             <entry>On 32-bit x86 systems, the first x86 root partition on the disk the EFI ESP is located on is mounted to the root directory <filename>/</filename>.</entry>
 109           </row>
 110           <row>
 111             <entry>4f68bce3-e8cd-4db1-96e7-fbcaf984b709</entry>
 112             <entry><filename>Root Partition (x86-64)</filename></entry>
 113             <entry>On 64-bit x86 systems, the first x86-64 root partition on the disk the EFI ESP is located on is mounted to the root directory <filename>/</filename>.</entry>
 114           </row>
 115           <row>
 116             <entry>69dad710-2ce4-4e3c-b16c-21a1d49abed3</entry>
 117             <entry><filename>Root Partition (32-bit ARM)</filename></entry>
 118             <entry>On 32-bit ARM systems, the first ARM root partition on the disk the EFI ESP is located on is mounted to the root directory <filename>/</filename>.</entry>
 119           </row>
 120           <row>
 121             <entry>b921b045-1df0-41c3-af44-4c6f280d3fae</entry>
 122             <entry><filename>Root Partition (64-bit ARM)</filename></entry>
 123             <entry>On 64-bit ARM systems, the first ARM root partition on the disk the EFI ESP is located on is mounted to the root directory <filename>/</filename>.</entry>
 124           </row>
 125           <row>
 126             <entry>933ac7e1-2eb4-4f13-b844-0e14e2aef915</entry>
 127             <entry>Home Partition</entry>
 128             <entry>The first home partition on the disk the root partition is located on is mounted to <filename>/home</filename>.</entry>
 129           </row>
 130           <row>
 131             <entry>3b8f8425-20e0-4f3b-907f-1a25a76f98e8</entry>
 132             <entry>Server Data Partition</entry>
 133             <entry>The first server data partition on the disk the root partition is located on is mounted to <filename>/srv</filename>.</entry>
 134           </row>
 135           <row>
 136             <entry>0657fd6d-a4ab-43c4-84e5-0933c84b4f4f</entry>
 137             <entry>Swap</entry>
 138             <entry>All swap partitions located on the disk the root partition is located on are enabled.</entry>
 139           </row>
 140         </tbody>
 141       </tgroup>
 142     </table>
 143
 144     <para>The <filename>/home</filename> and <filename>/srv</filename>
 145     partitions may be encrypted in LUKS format. In this case, a device
 146     mapper device is set up under the names
 147     <filename>/dev/mapper/home</filename> and
 148     <filename>/dev/mapper/srv</filename>. Note that this might create
 149     conflicts if the same partition is listed in
 150     <filename>/etc/crypttab</filename> with a different device mapper
 151     device name.</para>
 152
 153     <para>Mount and automount units for the EFI System Partition (ESP),
 154     mounting it to <filename>/boot</filename>, are generated on EFI
 155     systems where the boot loader communicates the used ESP to the operating
 156     system. Since this generator creates an automount unit, the mount will
 157     only be activated on-demand, when accessed. On systems where
 158     <filename>/boot</filename> is an explicitly configured mount
 159     (for example, listed in
 160     <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>)
 161     or where the <filename>/boot</filename> mount point is non-empty, no
 162     mount units are generated.</para>
 163
 164     <para>When using this generator in conjunction with btrfs file
 165     systems, make sure to set the correct default subvolumes on them,
 166     using <command>btrfs subvolume set-default</command>.</para>
 167
 168     <para><filename>systemd-gpt-auto-generator</filename> implements
 169     <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
 170   </refsect1>
 171
 172   <refsect1>
 173     <title>See Also</title>
 174     <para>
 175       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 176       <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 177       <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 178       <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 179       <citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 180       <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 181       <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 182       <citerefentry project='man-pages'><refentrytitle>btrfs</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 183     </para>
 184   </refsect1>
 185
 186 </refentry>