diff --git a/man/bootctl.xml b/man/bootctl.xml index 5dfed110dd..5f5f137f8a 100644 --- a/man/bootctl.xml +++ b/man/bootctl.xml @@ -239,15 +239,25 @@ - Control creation and deletion of $ESP/$MACHINE_ID during - and , respectively. - auto is equivalent to to yes if /etc/machine-id - resides on a filesystem other than tmpfs and no otherwise. - Defaults to auto. + Control creation and deletion of the top-level machine ID directory on the file + system containing boot loader entries (i.e. beneath the file system returned by + --print-boot-path above) during and + , respectively. auto is equivalent to + yes if /etc/machine-id resides on a filesystem other than + tmpfs and no otherwise (in the latter case the machine ID is likely transient and + hence should not be used persistently in the ESP). Defaults to auto. See + machine-id5 for + details about the machine ID concept and file. - Overriding this may be desired to hide the machine ID from the (unencrypted) ESP, - configure a kernel-install8 script, or, - conversely, commit a machine-id that only appears transient. + Overriding this may be desirable to hide the machine ID from the (unencrypted) ESP, configure a + kernel-install8 + script, or, conversely, commit a transient machine ID. + + The top-level machine ID directory is useful to allow smooth multi-boot installations: each + installed OS instance will have a different machine ID and thus a separate directory to place its + boot-time resources in. If this feature is turned off with this option, care needs to be taken that + multiple OS instances do not place conflicting files on the shared ESP and Extended Boot Loader + Partitions, or that multiple OS instances are not possible.