[thirdparty/systemd.git] / man / systemd-gpt-auto-generator.xml

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<!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+
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<refentry id="systemd-gpt-auto-generator">

  <refentryinfo>
    <title>systemd-gpt-auto-generator</title>
    <productname>systemd</productname>

    <authorgroup>
      <author>
        <contrib>Developer</contrib>
        <firstname>Lennart</firstname>
        <surname>Poettering</surname>
        <email>lennart@poettering.net</email>
      </author>
    </authorgroup>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd-gpt-auto-generator</refentrytitle>
    <manvolnum>8</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd-gpt-auto-generator</refname>
    <refpurpose>Generator for automatically discovering
    and mounting root, <filename>/home</filename> and
    <filename>/srv</filename> partitions, as well as
    discovering and enabling swap partitions, based on GPT
    partition type GUIDs.</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <para><filename>/usr/lib/systemd/system-generators/systemd-gpt-auto-generator</filename></para>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><filename>systemd-gpt-auto-generator</filename> is a unit
    generator that automatically discovers root,
    <filename>/home</filename>, <filename>/srv</filename> and swap
    partitions and creates mount and swap units for them, based on the
    partition type GUIDs of GUID partition tables (GPT),
    see <ulink url="http://www.uefi.org/specifications">UEFI Specification</ulink>, chapter 5.
    It implements the <ulink
    url="https://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/">Discoverable
    Partitions Specification</ulink>. Note that this generator has no
    effect on non-GPT systems, or where the directories under the
    mount points are already non-empty. Also, on systems where the
    units are explicitly configured (for example, listed in
    <citerefentry
    project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>),
    the units this generator creates are overridden, but additional
    implicit dependencies might be created.</para>

    <para>This generator will only look for root partitions on the
    same physical disk the EFI System Partition (ESP) is located on.
    It will only look for the other partitions on the same physical
    disk the root file system is located on. These partitions will not
    be searched for on systems where the root file system is distributed
    on multiple disks, for example via btrfs RAID.</para>

    <para><filename>systemd-gpt-auto-generator</filename> is useful
    for centralizing file system configuration in the partition table
    and making configuration in <filename>/etc/fstab</filename> unnecessary.
    </para>

    <para>This generator looks for the partitions based on their
    partition type GUID. The following partition type GUIDs are
    identified:</para>

    <table>
      <title>Partition Type GUIDs</title>
      <tgroup cols='3' align='left' colsep='1' rowsep='1'>
        <colspec colname="guid" />
        <colspec colname="name" />
        <colspec colname="explanation" />
        <thead>
          <row>
            <entry>Partition Type GUID</entry>
            <entry>Name</entry>
            <entry>Explanation</entry>
          </row>
        </thead>
        <tbody>
          <row>
            <entry>44479540-f297-41b2-9af7-d131d5f0458a</entry>
            <entry><filename>Root Partition (x86)</filename></entry>
            <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>
          </row>
          <row>
            <entry>4f68bce3-e8cd-4db1-96e7-fbcaf984b709</entry>
            <entry><filename>Root Partition (x86-64)</filename></entry>
            <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>
          </row>
          <row>
            <entry>69dad710-2ce4-4e3c-b16c-21a1d49abed3</entry>
            <entry><filename>Root Partition (32-bit ARM)</filename></entry>
            <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>
          </row>
          <row>
            <entry>b921b045-1df0-41c3-af44-4c6f280d3fae</entry>
            <entry><filename>Root Partition (64-bit ARM)</filename></entry>
            <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>
          </row>
          <row>
            <entry>993d8d3d-f80e-4225-855a-9daf8ed7ea97</entry>
            <entry><filename>Root Partition (Itanium/IA-64)</filename></entry>
            <entry>On Itanium systems, the first Itanium root partition on the disk the EFI ESP is located on is mounted to the root directory <filename>/</filename>.</entry>
          </row>
          <row>
            <entry>933ac7e1-2eb4-4f13-b844-0e14e2aef915</entry>
            <entry>Home Partition</entry>
            <entry>The first home partition on the disk the root partition is located on is mounted to <filename>/home</filename>.</entry>
          </row>
          <row>
            <entry>3b8f8425-20e0-4f3b-907f-1a25a76f98e8</entry>
            <entry>Server Data Partition</entry>
            <entry>The first server data partition on the disk the root partition is located on is mounted to <filename>/srv</filename>.</entry>
          </row>
          <row>
            <entry>0657fd6d-a4ab-43c4-84e5-0933c84b4f4f</entry>
            <entry>Swap</entry>
            <entry>All swap partitions located on the disk the root partition is located on are enabled.</entry>
          </row>
          <row>
            <entry>c12a7328-f81f-11d2-ba4b-00a0c93ec93b</entry>
            <entry>EFI System Partition (ESP)</entry>
            <entry>The first ESP located on the disk the root partition is located on is mounted to <filename>/boot</filename> or <filename>/efi</filename>, see below.</entry>
          </row>
        </tbody>
      </tgroup>
    </table>

    <para>This generator understands the following attribute flags for partitions:</para>

    <table>
      <title>Partition Attributes</title>
      <tgroup cols='4' align='left' colsep='1' rowsep='1'>
        <colspec colname="attribute" />
        <colspec colname="value" />
        <colspec colname="where" />
        <colspec colname="explanation" />
        <thead>
          <row>
            <entry>Name</entry>
            <entry>Value</entry>
            <entry>Applicable to</entry>
            <entry>Explanation</entry>
          </row>
        </thead>
        <tbody>
          <row>
            <entry><constant>GPT_FLAG_READ_ONLY</constant></entry>
            <entry>0x1000000000000000</entry>
            <entry><filename>/</filename>, <filename>/srv</filename>, <filename>/home</filename></entry>
            <entry>Partition is mounted read-only</entry>
          </row>

          <row>
            <entry><constant>GPT_FLAG_NO_AUTO</constant></entry>
            <entry>0x8000000000000000</entry>
            <entry><filename>/</filename>, <filename>/srv</filename>, <filename>/home</filename></entry>
            <entry>Partition is not mounted automatically</entry>
          </row>

          <row>
            <entry><constant>GPT_FLAG_NO_BLOCK_IO_PROTOCOL</constant></entry>
            <entry>0x0000000000000002</entry>
            <entry>ESP</entry>
            <entry>Partition is not mounted automatically</entry>
          </row>
        </tbody>
      </tgroup>
    </table>

    <para>The <filename>/home</filename> and <filename>/srv</filename>
    partitions may be encrypted in LUKS format. In this case, a device
    mapper device is set up under the names
    <filename>/dev/mapper/home</filename> and
    <filename>/dev/mapper/srv</filename>. Note that this might create
    conflicts if the same partition is listed in
    <filename>/etc/crypttab</filename> with a different device mapper
    device name.</para>

    <para>Mount and automount units for the EFI System Partition (ESP) are generated on EFI systems. The ESP is mounted
    to <filename>/boot</filename>, unless a mount point directory <filename>/efi</filename> exists, in which case it is
    mounted there. Since this generator creates an automount unit, the mount will only be activated on-demand, when
    accessed. On systems where <filename>/boot</filename> (or <filename>/efi</filename> if it exists) is an explicitly
    configured mount (for example, listed in <citerefentry
    project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>) or where the
    <filename>/boot</filename> (or <filename>/efi</filename>) mount point is non-empty, no mount units are
    generated.</para>

    <para>When using this generator in conjunction with btrfs file
    systems, make sure to set the correct default subvolumes on them,
    using <command>btrfs subvolume set-default</command>.</para>

    <para><filename>systemd-gpt-auto-generator</filename> implements
    <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry project='man-pages'><refentrytitle>btrfs</refentrytitle><manvolnum>8</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>
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d67ca9ab LP	1	<?xml version="1.0"?>
d67ca9ab LP	2	<!---nxml--->
12b42c76	3	<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
d67ca9ab	4	<!--
572eb058	5	SPDX-License-Identifier: LGPL-2.1+
d67ca9ab LP	6	-->
	7	<refentry id="systemd-gpt-auto-generator">
	8
798d3a52 ZJS	9	<refentryinfo>
	10	<title>systemd-gpt-auto-generator</title>
	11	<productname>systemd</productname>
	12
	13	<authorgroup>
	14	<author>
	15	<contrib>Developer</contrib>
	16	<firstname>Lennart</firstname>
	17	<surname>Poettering</surname>
	18	<email>lennart@poettering.net</email>
	19	</author>
	20	</authorgroup>
	21	</refentryinfo>
	22
	23	<refmeta>
	24	<refentrytitle>systemd-gpt-auto-generator</refentrytitle>
	25	<manvolnum>8</manvolnum>
	26	</refmeta>
	27
	28	<refnamediv>
	29	<refname>systemd-gpt-auto-generator</refname>
	30	<refpurpose>Generator for automatically discovering
	31	and mounting root, <filename>/home</filename> and
	32	<filename>/srv</filename> partitions, as well as
	33	discovering and enabling swap partitions, based on GPT
	34	partition type GUIDs.</refpurpose>
	35	</refnamediv>
	36
	37	<refsynopsisdiv>
12b42c76	38	<para><filename>/usr/lib/systemd/system-generators/systemd-gpt-auto-generator</filename></para>
798d3a52 ZJS	39	</refsynopsisdiv>
	40
	41	<refsect1>
	42	<title>Description</title>
	43
	44	<para><filename>systemd-gpt-auto-generator</filename> is a unit
	45	generator that automatically discovers root,
	46	<filename>/home</filename>, <filename>/srv</filename> and swap
	47	partitions and creates mount and swap units for them, based on the
8d5a4f27 ZJS	48	partition type GUIDs of GUID partition tables (GPT),
	49	see <ulink url="http://www.uefi.org/specifications">UEFI Specification</ulink>, chapter 5.
	50	It implements the <ulink
28a0ad81	51	url="https://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/">Discoverable
798d3a52	52	Partitions Specification</ulink>. Note that this generator has no
c6355b31 LP	53	effect on non-GPT systems, or where the directories under the
	54	mount points are already non-empty. Also, on systems where the
	55	units are explicitly configured (for example, listed in
	56	<citerefentry
	57	project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>),
dc61b7e4	58	the units this generator creates are overridden, but additional
45f09f93	59	implicit dependencies might be created.</para>
798d3a52 ZJS	60
	61	<para>This generator will only look for root partitions on the
	62	same physical disk the EFI System Partition (ESP) is located on.
	63	It will only look for the other partitions on the same physical
	64	disk the root file system is located on. These partitions will not
8d5a4f27	65	be searched for on systems where the root file system is distributed
798d3a52 ZJS	66	on multiple disks, for example via btrfs RAID.</para>
	67
	68	<para><filename>systemd-gpt-auto-generator</filename> is useful
	69	for centralizing file system configuration in the partition table
8d5a4f27 ZJS	70	and making configuration in <filename>/etc/fstab</filename> unnecessary.
8d5a4f27 ZJS	71	</para>
798d3a52 ZJS	72
	73	<para>This generator looks for the partitions based on their
	74	partition type GUID. The following partition type GUIDs are
	75	identified:</para>
	76
	77	<table>
	78	<title>Partition Type GUIDs</title>
	79	<tgroup cols='3' align='left' colsep='1' rowsep='1'>
	80	<colspec colname="guid" />
	81	<colspec colname="name" />
	82	<colspec colname="explanation" />
	83	<thead>
	84	<row>
	85	<entry>Partition Type GUID</entry>
	86	<entry>Name</entry>
	87	<entry>Explanation</entry>
	88	</row>
	89	</thead>
	90	<tbody>
	91	<row>
	92	<entry>44479540-f297-41b2-9af7-d131d5f0458a</entry>
	93	<entry><filename>Root Partition (x86)</filename></entry>
	94	<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>
	95	</row>
	96	<row>
	97	<entry>4f68bce3-e8cd-4db1-96e7-fbcaf984b709</entry>
	98	<entry><filename>Root Partition (x86-64)</filename></entry>
	99	<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>
	100	</row>
	101	<row>
	102	<entry>69dad710-2ce4-4e3c-b16c-21a1d49abed3</entry>
	103	<entry><filename>Root Partition (32-bit ARM)</filename></entry>
	104	<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>
	105	</row>
	106	<row>
	107	<entry>b921b045-1df0-41c3-af44-4c6f280d3fae</entry>
	108	<entry><filename>Root Partition (64-bit ARM)</filename></entry>
	109	<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>
	110	</row>
b793ddfa LW	111	<row>
	112	<entry>993d8d3d-f80e-4225-855a-9daf8ed7ea97</entry>
	113	<entry><filename>Root Partition (Itanium/IA-64)</filename></entry>
	114	<entry>On Itanium systems, the first Itanium root partition on the disk the EFI ESP is located on is mounted to the root directory <filename>/</filename>.</entry>
	115	</row>
798d3a52 ZJS	116	<row>
	117	<entry>933ac7e1-2eb4-4f13-b844-0e14e2aef915</entry>
	118	<entry>Home Partition</entry>
	119	<entry>The first home partition on the disk the root partition is located on is mounted to <filename>/home</filename>.</entry>
	120	</row>
	121	<row>
	122	<entry>3b8f8425-20e0-4f3b-907f-1a25a76f98e8</entry>
	123	<entry>Server Data Partition</entry>
	124	<entry>The first server data partition on the disk the root partition is located on is mounted to <filename>/srv</filename>.</entry>
	125	</row>
	126	<row>
	127	<entry>0657fd6d-a4ab-43c4-84e5-0933c84b4f4f</entry>
	128	<entry>Swap</entry>
	129	<entry>All swap partitions located on the disk the root partition is located on are enabled.</entry>
	130	</row>
b52a109a LP	131	<row>
	132	<entry>c12a7328-f81f-11d2-ba4b-00a0c93ec93b</entry>
	133	<entry>EFI System Partition (ESP)</entry>
	134	<entry>The first ESP located on the disk the root partition is located on is mounted to <filename>/boot</filename> or <filename>/efi</filename>, see below.</entry>
	135	</row>
798d3a52 ZJS	136	</tbody>
	137	</tgroup>
	138	</table>
	139
8d5a4f27 ZJS	140	<para>This generator understands the following attribute flags for partitions:</para>
	141
	142	<table>
	143	<title>Partition Attributes</title>
	144	<tgroup cols='4' align='left' colsep='1' rowsep='1'>
	145	<colspec colname="attribute" />
	146	<colspec colname="value" />
	147	<colspec colname="where" />
	148	<colspec colname="explanation" />
	149	<thead>
	150	<row>
	151	<entry>Name</entry>
	152	<entry>Value</entry>
	153	<entry>Applicable to</entry>
	154	<entry>Explanation</entry>
	155	</row>
	156	</thead>
	157	<tbody>
	158	<row>
	159	<entry><constant>GPT_FLAG_READ_ONLY</constant></entry>
	160	<entry>0x1000000000000000</entry>
	161	<entry><filename>/</filename>, <filename>/srv</filename>, <filename>/home</filename></entry>
	162	<entry>Partition is mounted read-only</entry>
	163	</row>
	164
	165	<row>
	166	<entry><constant>GPT_FLAG_NO_AUTO</constant></entry>
	167	<entry>0x8000000000000000</entry>
	168	<entry><filename>/</filename>, <filename>/srv</filename>, <filename>/home</filename></entry>
	169	<entry>Partition is not mounted automatically</entry>
	170	</row>
	171
	172	<row>
	173	<entry><constant>GPT_FLAG_NO_BLOCK_IO_PROTOCOL</constant></entry>
	174	<entry>0x0000000000000002</entry>
	175	<entry>ESP</entry>
	176	<entry>Partition is not mounted automatically</entry>
	177	</row>
	178	</tbody>
	179	</tgroup>
	180	</table>
	181
798d3a52	182	<para>The <filename>/home</filename> and <filename>/srv</filename>
b938cb90	183	partitions may be encrypted in LUKS format. In this case, a device
798d3a52 ZJS	184	mapper device is set up under the names
	185	<filename>/dev/mapper/home</filename> and
	186	<filename>/dev/mapper/srv</filename>. Note that this might create
	187	conflicts if the same partition is listed in
	188	<filename>/etc/crypttab</filename> with a different device mapper
	189	device name.</para>
	190
b52a109a LP	191	<para>Mount and automount units for the EFI System Partition (ESP) are generated on EFI systems. The ESP is mounted
	192	to <filename>/boot</filename>, unless a mount point directory <filename>/efi</filename> exists, in which case it is
	193	mounted there. Since this generator creates an automount unit, the mount will only be activated on-demand, when
	194	accessed. On systems where <filename>/boot</filename> (or <filename>/efi</filename> if it exists) is an explicitly
	195	configured mount (for example, listed in <citerefentry
	196	project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>) or where the
	197	<filename>/boot</filename> (or <filename>/efi</filename>) mount point is non-empty, no mount units are
	198	generated.</para>
798d3a52 ZJS	199
	200	<para>When using this generator in conjunction with btrfs file
	201	systems, make sure to set the correct default subvolumes on them,
	202	using <command>btrfs subvolume set-default</command>.</para>
	203
	204	<para><filename>systemd-gpt-auto-generator</filename> implements
b1c1a519	205	<citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
798d3a52 ZJS	206	</refsect1>
	207
	208	<refsect1>
	209	<title>See Also</title>
	210	<para>
	211	<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
	212	<citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
	213	<citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
	214	<citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
798d3a52	215	<citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
3ba3a79d ZJS	216	<citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
	217	<citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
	218	<citerefentry project='man-pages'><refentrytitle>btrfs</refentrytitle><manvolnum>8</manvolnum></citerefentry>
798d3a52 ZJS	219	</para>
798d3a52 ZJS	220	</refsect1>
d67ca9ab LP	221
d67ca9ab LP	222	</refentry>