<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>
+ <refpurpose>Generator for automatically discovering and mounting root, <filename>/home/</filename>,
+ <filename>/srv/</filename>, <filename>/var/</filename> and <filename>/var/tmp/</filename> partitions, as
+ well as discovering and enabling swap partitions, based on GPT partition type GUIDs</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Description</title>
<para><filename>systemd-gpt-auto-generator</filename> is a unit generator that automatically discovers
- root, <filename>/home/</filename>, <filename>/srv/</filename>, the EFI System Partition, the Extended
- Boot Loader Partition 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="https://uefi.org/specifications">UEFI Specification</ulink>, chapter 5. It implements the <ulink
- url="https://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/">Discoverable Partitions
+ root, <filename>/home/</filename>, <filename>/srv/</filename>, <filename>/var/</filename>,
+ <filename>/var/tmp/</filename>, the EFI System Partition, the Extended Boot Loader Partition 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="https://uefi.org/specifications">UEFI Specification</ulink>, chapter 5. It
+ implements the <ulink url="https://systemd.io/DISCOVERABLE_PARTITIONS">Discoverable Partitions
Specification</ulink>. Note that this generator has no effect on non-GPT systems, and on specific mount
points that are directories already containing files. Also, on systems where the units are explicitly
configured (for example, listed in <citerefentry
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>This generator will only look for the root partition on the same physical disk the EFI System
+ Partition (ESP) is located on. Note that support from the boot loader is required: the EFI variable
+ <varname>LoaderDevicePartUUID</varname> of the <constant>4a67b082-0a4c-41cf-b6c7-440b29bb8c4f</constant>
+ vendor UUID is used to determine from which partition, and hence the disk from which the system was
+ booted. If the boot loader does not set this variable, this generator will not be able to autodetect the
+ root partition. See the <ulink url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader
+ Interface</ulink> for details.</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>Similarly, this generator will only look for the other partitions on the same physical disk as the
+ root partition. In this case, boot loader support is not required. 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> or on
+ the kernel command line unnecessary.</para>
+
<para>This generator looks for the partitions based on their
partition type GUID. The following partition type GUIDs are
identified:</para>
<entry>933ac7e1-2eb4-4f13-b844-0e14e2aef915</entry>
<entry>Home Partition</entry>
<entry><filename>/home/</filename></entry>
- <entry>The first home partition on the disk the root partition is located on is mounted to <filename>/home</filename>.</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><filename>/srv/</filename></entry>
- <entry>The first server data partition on the disk the root partition is located on is mounted to <filename>/srv</filename>.</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>4d21b016-b534-45c2-a9fb-5c16e091fd2d</entry>
+ <entry>Variable Data Partition</entry>
+ <entry><filename>/var/</filename></entry>
+ <entry>The first variable data partition on the disk the root partition is located on is mounted to <filename>/var/</filename> — under the condition its partition UUID matches the first 128 bit of the HMAC-SHA256 of the GPT type uuid of this partition keyed by the machine ID of the installation stored in <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</entry>
+ </row>
+ <row>
+ <entry>7ec6f557-3bc5-4aca-b293-16ef5df639d1</entry>
+ <entry>Temporary Data Partition</entry>
+ <entry><filename>/var/tmp/</filename></entry>
+ <entry>The first temporary data partition on the disk the root partition is located on is mounted to <filename>/var/tmp/</filename>.</entry>
</row>
<row>
<entry>0657fd6d-a4ab-43c4-84e5-0933c84b4f4f</entry>
<entry>c12a7328-f81f-11d2-ba4b-00a0c93ec93b</entry>
<entry>EFI System Partition (ESP)</entry>
<entry><filename>/efi/</filename> or <filename>/boot/</filename></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>
+ <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>
<row>
<entry>bc13c2ff-59e6-4262-a352-b275fd6f7172</entry>
<entry>Extended Boot Loader Partition</entry>
<entry><filename>/boot/</filename></entry>
- <entry>The first Extended Boot Loader Partition is mounted to <filename>/boot</filename>, see below.</entry>
+ <entry>The first Extended Boot Loader Partition is mounted to <filename>/boot/</filename>, see below.</entry>
</row>
</tbody>
</tgroup>
<row>
<entry><constant>GPT_FLAG_READ_ONLY</constant></entry>
<entry>0x1000000000000000</entry>
- <entry><filename>/</filename>, <filename>/home/</filename>, <filename>/srv/</filename>, Extended Boot Loader Partition</entry>
+ <entry><filename>/</filename>, <filename>/home/</filename>, <filename>/srv/</filename>, <filename>/var/</filename>, <filename>/var/tmp/</filename>, Extended Boot Loader Partition</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>/home/</filename>, <filename>/srv/</filename>, Extended Boot Loader Partition</entry>
+ <entry><filename>/</filename>, <filename>/home/</filename>, <filename>/srv/</filename>, <filename>/var/</filename>, <filename>/var/tmp/</filename>, Extended Boot Loader Partition</entry>
<entry>Partition is not mounted automatically</entry>
</row>
</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>The <filename>/home/</filename>, <filename>/srv/</filename>, <filename>/var/</filename> and
+ <filename>/var/tmp/</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>,
+ <filename>/dev/mapper/srv</filename>, <filename>/dev/mapper/var</filename> and
+ <filename>/dev/mapper/tmp</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>When systemd is running in the initrd the <filename>/</filename> partition may be encrypted in LUKS
+ format as well. In this case, a device mapper device is set up under the name <filename>/dev/mapper/root</filename>,
+ and a <filename>sysroot.mount</filename> is set up that mounts the device under <filename>/sysroot</filename>.
+ For more information, see <citerefentry><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
+ </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> (except if an Extended Boot Loader partition exists, see
<para>If the disk contains an Extended Boot Loader partition, as defined in the <ulink
url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader Specification</ulink>, it is made
- available at <filename>/boot</filename> (by means of an automount point, similar to the ESP, see
+ available at <filename>/boot/</filename> (by means of an automount point, similar to the ESP, see
above). If both an EFI System Partition and an Extended Boot Loader partition exist the latter is
preferably mounted to <filename>/boot/</filename>. Make sure to create both <filename>/efi/</filename>
and <filename>/boot/</filename> to ensure both partitions are mounted.</para>
<term><varname>root=</varname></term>
<listitem><para>When used with the special value <literal>gpt-auto</literal>, automatic discovery of
- the root parition based on the GPT partition type is enabled. Any other value disables this
+ the root partition based on the GPT partition type is enabled. Any other value disables this
generator.</para></listitem>
</varlistentry>
<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><refentrytitle>machine-id</refentrytitle><manvolnum>5</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>
projects / thirdparty / systemd.git / blobdiff