{ "content": [ { "type": "text", "text": "# systemd-gpt-auto-generator (info)\n\n## NAME\n\nsystemd-gpt-auto-generator - Generator for automatically discovering and mounting root, /home/, /srv/, /var/ and /var/tmp/ partitions, as well as discovering and enabling swap partitions, based on GPT partition type GUIDs\n\n## SYNOPSIS\n\n/lib/systemd/system-generators/systemd-gpt-auto-generator\n\n## DESCRIPTION\n\nsystemd-gpt-auto-generator is a unit generator that automatically\ndiscovers root, /home/, /srv/, /var/, /var/tmp/, the EFI System\nPartition, the Extended Boot Loader Partition and swap partitions and\ncreates mount and swap units for them, based on the partition type\nGUIDs of GUID partition tables (GPT), see UEFI Specification[1],\nchapter 5. It implements the Discoverable Partitions Specification[2].\nNote that this generator has no effect on non-GPT systems, and on\nspecific mount points that are directories already containing files.\nAlso, on systems where the units are explicitly configured (for\nexample, listed in fstab(5)), the units this generator creates are\noverridden, but additional implicit dependencies might be created.\n\n## Sections\n\n- **NAME**\n- **SYNOPSIS**\n- **DESCRIPTION**\n- **KERNEL COMMAND LINE**\n- **SEE ALSO**\n- **NOTES**\n\nUse structuredContent.sections for detailed options, examples, and full documentation.\n" } ], "structuredContent": { "command": "systemd-gpt-auto-generator", "section": "", "mode": "info", "summary": "systemd-gpt-auto-generator - Generator for automatically discovering and mounting root, /home/, /srv/, /var/ and /var/tmp/ partitions, as well as discovering and enabling swap partitions, based on GPT partition type GUIDs", "synopsis": "/lib/systemd/system-generators/systemd-gpt-auto-generator", "tldr_summary": null, "tldr_examples": [], "tldr_source": null, "flags": [], "examples": [], "see_also": [ { "name": "systemd", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/systemd/1/json" }, { "name": "systemd.mount", "section": "5", "url": "https://www.chedong.com/phpMan.php/man/systemd.mount/5/json" }, { "name": "systemd.swap", "section": "5", "url": "https://www.chedong.com/phpMan.php/man/systemd.swap/5/json" }, { "name": "generator", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/generator/8/json" }, { "name": ".service", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/.service/8/json" }, { "name": "machine-id", "section": "5", "url": "https://www.chedong.com/phpMan.php/man/machine-id/5/json" }, { "name": "cryptsetup", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/cryptsetup/8/json" }, { "name": "fstab", "section": "5", "url": "https://www.chedong.com/phpMan.php/man/fstab/5/json" }, { "name": "btrfs", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/btrfs/8/json" } ], "section_outline": [ { "name": "NAME", "lines": 5, "subsections": [] }, { "name": "SYNOPSIS", "lines": 2, "subsections": [] }, { "name": "DESCRIPTION", "lines": 244, "subsections": [] }, { "name": "KERNEL COMMAND LINE", "lines": 20, "subsections": [] }, { "name": "SEE ALSO", "lines": 4, "subsections": [] }, { "name": "NOTES", "lines": 13, "subsections": [] } ], "sections": { "NAME": { "content": "systemd-gpt-auto-generator - Generator for automatically discovering\nand mounting root, /home/, /srv/, /var/ and /var/tmp/ partitions, as\nwell as discovering and enabling swap partitions, based on GPT\npartition type GUIDs\n", "subsections": [] }, "SYNOPSIS": { "content": "/lib/systemd/system-generators/systemd-gpt-auto-generator\n", "subsections": [] }, "DESCRIPTION": { "content": "systemd-gpt-auto-generator is a unit generator that automatically\ndiscovers root, /home/, /srv/, /var/, /var/tmp/, the EFI System\nPartition, the Extended Boot Loader Partition and swap partitions and\ncreates mount and swap units for them, based on the partition type\nGUIDs of GUID partition tables (GPT), see UEFI Specification[1],\nchapter 5. It implements the Discoverable Partitions Specification[2].\nNote that this generator has no effect on non-GPT systems, and on\nspecific mount points that are directories already containing files.\nAlso, on systems where the units are explicitly configured (for\nexample, listed in fstab(5)), the units this generator creates are\noverridden, but additional implicit dependencies might be created.\n\nThis generator will only look for the root partition on the same\nphysical disk the EFI System Partition (ESP) is located on. Note that\nsupport from the boot loader is required: the EFI variable\nLoaderDevicePartUUID of the 4a67b082-0a4c-41cf-b6c7-440b29bb8c4f vendor\nUUID is used to determine from which partition, and hence the disk from\nwhich the system was booted. If the boot loader does not set this\nvariable, this generator will not be able to autodetect the root\npartition. See the Boot Loader Interface[3] for details.\n\nSimilarly, this generator will only look for the other partitions on\nthe same physical disk as the root partition. In this case, boot loader\nsupport is not required. These partitions will not be searched for on\nsystems where the root file system is distributed on multiple disks,\nfor example via btrfs RAID.\n\nsystemd-gpt-auto-generator is useful for centralizing file system\nconfiguration in the partition table and making configuration in\n/etc/fstab or on the kernel command line unnecessary.\n\nThis generator looks for the partitions based on their partition type\nGUID. The following partition type GUIDs are identified:\n\nTable 1. Partition Type GUIDs\n+-------------------------------------+------------------+-----------------+------------------+\n|Partition Type | Name | Mount Point | Explanation |\n|GUID | | | |\n+-------------------------------------+------------------+-----------------+------------------+\n|44479540-f297-41b2-9af7-d131d5f0458a | Root Partition | / | On 32-bit x86 |\n| | (x86) | | systems, the |\n| | | | first x86 root |\n| | | | partition on the |\n| | | | disk the EFI ESP |\n| | | | is located on is |\n| | | | mounted to the |\n| | | | root directory |\n| | | | /. |\n+-------------------------------------+------------------+-----------------+------------------+\n|4f68bce3-e8cd-4db1-96e7-fbcaf984b709 | Root Partition | / | On 64-bit x86 |\n| | (x86-64) | | systems, the |\n| | | | first x86-64 |\n| | | | root partition |\n| | | | on the disk the |\n| | | | EFI ESP is |\n| | | | located on is |\n| | | | mounted to the |\n| | | | root directory |\n| | | | /. |\n+-------------------------------------+------------------+-----------------+------------------+\n|69dad710-2ce4-4e3c-b16c-21a1d49abed3 | Root Partition | / | On 32-bit ARM |\n| | (32-bit ARM) | | systems, the |\n| | | | first ARM root |\n| | | | partition on the |\n| | | | disk the EFI ESP |\n| | | | is located on is |\n| | | | mounted to the |\n| | | | root directory |\n| | | | /. |\n+-------------------------------------+------------------+-----------------+------------------+\n|b921b045-1df0-41c3-af44-4c6f280d3fae | Root Partition | / | On 64-bit ARM |\n| | (64-bit ARM) | | systems, the |\n| | | | first ARM root |\n| | | | partition on the |\n| | | | disk the EFI ESP |\n| | | | is located on is |\n| | | | mounted to the |\n| | | | root directory |\n| | | | /. |\n+-------------------------------------+------------------+-----------------+------------------+\n|993d8d3d-f80e-4225-855a-9daf8ed7ea97 | Root Partition | / | On Itanium |\n| | (Itanium/IA-64) | | systems, the |\n| | | | first Itanium |\n| | | | root partition |\n| | | | on the disk the |\n| | | | EFI ESP is |\n| | | | located on is |\n| | | | mounted to the |\n| | | | root directory |\n| | | | /. |\n+-------------------------------------+------------------+-----------------+------------------+\n|60d5a7fe-8e7d-435c-b714-3dd8162144e1 | Root Partition | / | On RISC-V 32-bit |\n| | (RISCV-V 32) | | systems, the |\n| | | | first RISCV-V |\n| | | | 32-bit root |\n| | | | partition on the |\n| | | | disk the EFI ESP |\n| | | | is located on is |\n| | | | mounted to the |\n| | | | root directory |\n| | | | /. |\n+-------------------------------------+------------------+-----------------+------------------+\n|72ec70a6-cf74-40e6-bd49-4bda08e8f224 | Root Partition | / | On RISC-V 64-bit |\n| | (RISCV-V 64) | | systems, the |\n| | | | first RISCV-V |\n| | | | 64-bit root |\n| | | | partition on the |\n| | | | disk the EFI ESP |\n| | | | is located on is |\n| | | | mounted to the |\n| | | | root directory |\n| | | | /. |\n+-------------------------------------+------------------+-----------------+------------------+\n|933ac7e1-2eb4-4f13-b844-0e14e2aef915 | Home Partition | /home/ | The first home |\n| | | | partition on the |\n| | | | disk the root |\n| | | | partition is |\n| | | | located on is |\n| | | | mounted to |\n| | | | /home/. |\n+-------------------------------------+------------------+-----------------+------------------+\n|3b8f8425-20e0-4f3b-907f-1a25a76f98e8 | Server Data | /srv/ | The first server |\n| | Partition | | data partition |\n| | | | on the disk the |\n| | | | root partition |\n| | | | is located on is |\n| | | | mounted to |\n| | | | /srv/. |\n+-------------------------------------+------------------+-----------------+------------------+\n|4d21b016-b534-45c2-a9fb-5c16e091fd2d | Variable Data | /var/ | The first |\n| | Partition | | variable data |\n| | | | partition on the |\n| | | | disk the root |\n| | | | partition is |\n| | | | located on is |\n| | | | mounted to /var/ |\n| | | | -- under the |\n| | | | condition its |\n| | | | partition UUID |\n| | | | matches the |\n| | | | first 128 bit of |\n| | | | the HMAC-SHA256 |\n| | | | of the GPT type |\n| | | | uuid of this |\n| | | | partition keyed |\n| | | | by the machine |\n| | | | ID of the |\n| | | | installation |\n| | | | stored in |\n| | | | machine-id(5). |\n+-------------------------------------+------------------+-----------------+------------------+\n|7ec6f557-3bc5-4aca-b293-16ef5df639d1 | Temporary Data | /var/tmp/ | The first |\n| | Partition | | temporary data |\n| | | | partition on the |\n| | | | disk the root |\n| | | | partition is |\n| | | | located on is |\n| | | | mounted to |\n| | | | /var/tmp/. |\n+-------------------------------------+------------------+-----------------+------------------+\n|0657fd6d-a4ab-43c4-84e5-0933c84b4f4f | Swap | n/a | All swap |\n| | | | partitions |\n| | | | located on the |\n| | | | disk the root |\n| | | | partition is |\n| | | | located on are |\n| | | | enabled. |\n+-------------------------------------+------------------+-----------------+------------------+\n|c12a7328-f81f-11d2-ba4b-00a0c93ec93b | EFI System | /efi/ or /boot/ | The first ESP |\n| | Partition (ESP) | | located on the |\n| | | | disk the root |\n| | | | partition is |\n| | | | located on is |\n| | | | mounted to |\n| | | | /boot/ or /efi/, |\n| | | | see below. |\n+-------------------------------------+------------------+-----------------+------------------+\n|bc13c2ff-59e6-4262-a352-b275fd6f7172 | Extended Boot | /boot/ | The first |\n| | Loader Partition | | Extended Boot |\n| | | | Loader Partition |\n| | | | is mounted to |\n| | | | /boot/, see |\n| | | | below. |\n+-------------------------------------+------------------+-----------------+------------------+\n\nThis generator understands the following attribute flags for\npartitions:\n\nTable 2. Partition Attributes\n+------------------------------+--------------------+------------------+------------------+\n|Name | Value | Applicable to | Explanation |\n+------------------------------+--------------------+------------------+------------------+\n|GPTFLAGREADONLY | 0x1000000000000000 | /, /home/, | Partition is |\n| | | /srv/, /var/, | mounted |\n| | | /var/tmp/, | read-only |\n| | | Extended Boot | |\n| | | Loader Partition | |\n+------------------------------+--------------------+------------------+------------------+\n|GPTFLAGNOAUTO | 0x8000000000000000 | /, /home/, | Partition is not |\n| | | /srv/, /var/, | mounted |\n| | | /var/tmp/, | automatically |\n| | | Extended Boot | |\n| | | Loader Partition | |\n+------------------------------+--------------------+------------------+------------------+\n|GPTFLAGNOBLOCKIOPROTOCOL | 0x0000000000000002 | EFI System | Partition is not |\n| | | Partition (ESP) | mounted |\n| | | | automatically |\n+------------------------------+--------------------+------------------+------------------+\n\nThe /home/, /srv/, /var/ and /var/tmp/ partitions may be encrypted in\nLUKS format. In this case, a device mapper device is set up under the\nnames /dev/mapper/home, /dev/mapper/srv, /dev/mapper/var and\n/dev/mapper/tmp. Note that this might create conflicts if the same\npartition is listed in /etc/crypttab with a different device mapper\ndevice name.\n\nWhen systemd is running in the initrd the / partition may be encrypted\nin LUKS format as well. In this case, a device mapper device is set up\nunder the name /dev/mapper/root, and a sysroot.mount is set up that\nmounts the device under /sysroot. For more information, see bootup(7).\n\nMount and automount units for the EFI System Partition (ESP) are\ngenerated on EFI systems. The ESP is mounted to /boot/ (except if an\nExtended Boot Loader partition exists, see below), unless a mount point\ndirectory /efi/ exists, in which case it is mounted there. Since this\ngenerator creates an automount unit, the mount will only be activated\non-demand, when accessed. On systems where /boot/ (or /efi/ if it\nexists) is an explicitly configured mount (for example, listed in\nfstab(5)) or where the /boot/ (or /efi/) mount point is non-empty, no\nmount units are generated.\n\nIf the disk contains an Extended Boot Loader partition, as defined in\nthe Boot Loader Specification[4], it is made available at /boot/ (by\nmeans of an automount point, similar to the ESP, see above). If both an\nEFI System Partition and an Extended Boot Loader partition exist the\nlatter is preferably mounted to /boot/. Make sure to create both /efi/\nand /boot/ to ensure both partitions are mounted.\n\nWhen using this generator in conjunction with btrfs file systems, make\nsure to set the correct default subvolumes on them, using btrfs\nsubvolume set-default.\n\nsystemd-gpt-auto-generator implements systemd.generator(7).\n", "subsections": [] }, "KERNEL COMMAND LINE": { "content": "systemd-gpt-auto-generator understands the following kernel command\nline parameters:\n\nsystemd.gptauto, rd.systemd.gptauto\nThose options take an optional boolean argument, and default to\nyes. The generator is enabled by default, and a negative value may\nbe used to disable it.\n\nroot=\nWhen used with the special value \"gpt-auto\", automatic discovery of\nthe root partition based on the GPT partition type is enabled. Any\nother value disables this generator.\n\nrw, ro\nMount the root partition read-write or read-only initially.\n\nNote that unlike most kernel command line options these settings do\nnot override configuration in the file system, and the file system\nmay be remounted later. See systemd-remount-fs.service(8).\n", "subsections": [] }, "SEE ALSO": { "content": "systemd(1), systemd.mount(5), systemd.swap(5), systemd-fstab-\ngenerator(8), systemd-cryptsetup@.service(8), machine-id(5),\ncryptsetup(8), fstab(5), btrfs(8)\n", "subsections": [] }, "NOTES": { "content": "1. UEFI Specification\nhttps://uefi.org/specifications\n\n2. Discoverable Partitions Specification\nhttps://systemd.io/DISCOVERABLEPARTITIONS\n\n3. Boot Loader Interface\nhttps://systemd.io/BOOTLOADERINTERFACE\n\n4. Boot Loader Specification\nhttps://systemd.io/BOOTLOADERSPECIFICATION\n\nsystemd 249 SYSTEMD-GPT-AUTO-GENERATOR(8)", "subsections": [] } } } }