systemd-gpt-auto-generator is a unit generator that automatically discovers root, /home, /srv and swap partitions and creates mount and swap units for them, based on the partition type GUIDs of GUID partition tables (GPT). It implements the m[blue]Discoverable Partitions Specificationm. 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 fstab(5)), the units this generator creates are overridden, but additional automatic dependencies might be created.
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 on systems where the root file system is distributed on multiple disks, for example via btrfs RAID.
systemd-gpt-auto-generator is useful for centralizing file system configuration in the partition table and making manual configuration in /etc/fstab or suchlike unnecessary.
This generator looks for the partitions based on their partition type GUID. The following partition type GUIDs are identified:
Table 1. Partition Type GUIDs
|Partition Type GUID
|Root Partition (x86)
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 /.
|Root Partition (x86-64)
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 /.
|Root Partition (32-bit ARM)
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 /.
|Root Partition (64-bit ARM)
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 /.
The first home partition on the disk the root partition is located on is mounted to /home.
|Server Data Partition
The first server data partition on the disk the root partition is located on is mounted to /srv.
All swap partitions located on the disk the root partition is located on are enabled.
The /home and /srv partitions may be encrypted in LUKS format. In this case, a device mapper device is set up under the names /dev/mapper/home and /dev/mapper/srv. Note that this might create conflicts if the same partition is listed in /etc/crypttab with a different device mapper device name.
Mount and automount units for the EFI System Partition (ESP), mounting it to /boot, are generated on EFI systems where the boot loader communicates the used ESP to the operating system. Since this generator creates an automount unit, the mount will only be activated on-demand, when accessed. On systems where /boot is an explicitly configured mount (for example, listed in fstab(5)) or where the /boot mount point is non-empty, no mount units are generated.
When using this generator in conjunction with btrfs file systems, make sure to set the correct default subvolumes on them, using btrfs subvolume set-default.
systemd-gpt-auto-generator implements systemd.generator(7).
Discoverable Partitions Specification