systemd.image-filter(7)

.SH "NAME" systemd.image-filter - Disk Image Dissection Filter

.SH "DESCRIPTION"

.PP In systemd, whenever a disk image (DDI) implementing the UAPI.2 Discoverable Partitions Specification[1] is activated, a filter may be specified controlling which partitions to consider for mounting. Such a disk image dissection filter is a string that contains per-partition-type patterns, separated by colons (:). The individual rules consist of a partition identifier, an equal sign (=), and a shell globbing pattern applied to the GPT label string of the partition. See glob(7) for details on shell globbing.

.PP The partition identifiers currently defined are: root, usr, home, srv, esp, xbootldr, swap, root-verity, root-verity-sig, usr-verity, usr-verity-sig, tmp, var. These identifiers match the relevant partition types in the Discoverable Partitions Specification, but are agnostic to CPU architectures.

.SH "USE"

.PP Various systemd components that support operating with disk images support a --image-filter= command line option to specify the image filter to use. If no filter is specified all partitions in partition table are considered and no per-label filtering is applied (except that partitions with the _empty label are always ignored).

.PP For the host root file system image itself systemd-gpt-auto-generator(8) is responsible for processing the GPT partition table and making use of the included discoverable partitions. It accepts an image filter via the kernel command line option systemd.image_filter=.

.SH "EXAMPLES"

.PP The following image filter string dictates that for the root file system partition only partitions shall be considered whose label begins with ParticleOS-. For the /usr/ partition the precise label ParticleOS_47110815 is required.

root=ParticleOS-*:usr=ParticleOS_47110815

.SH "SEE ALSO"

.PP systemd(1), systemd-dissect(1), systemd-gpt-auto-generator(8), systemd.image-policy(7)