Document managed root directory policy and kernel mount compatibility

This commit is contained in:
Codex
2026-10-13 23:15:59 +03:00
parent 1ae05a6823
commit ce04318b78
+12 -1
View File
@@ -12,6 +12,16 @@ subvolumes beneath `@root` are refused. Boot and fstab must select the filesyste
UUID plus `subvol=@root`, never a numeric root subvolume ID. `@home` and VM disks UUID plus `subvol=@root`, never a numeric root subvolume ID. `@home` and VM disks
stored there survive restoration; files stored elsewhere in `@root` roll back. stored there survive restoration; files stored elsewhere in `@root` roll back.
The image keeps `/srv`, `/var/lib/machines` and `/var/lib/portables` as ordinary
directories so that systemd does not create nested subvolumes on first boot.
Assembly copies the installed vendor `home.conf`, `systemd-nspawn.conf` and
`portables.conf` into `/etc/tmpfiles.d`, changing only those three creation rules.
Other vendor rules and the separate `/home` policy are preserved. Image rebuilds
regenerate these overrides and reject unexpected vendor rules. After a Portage
systemd update, review the overrides against the new `/usr/lib/tmpfiles.d` files;
existing `/etc` overrides continue to take precedence. Recovery still refuses
unknown nested subvolumes rather than silently omitting their contents.
This includes `/var/lib/hydra-update`: a full root restoration also restores the This includes `/var/lib/hydra-update`: a full root restoration also restores the
checkpoint's runtime update receipts and replay floor. The signed updater's checkpoint's runtime update receipts and replay floor. The signed updater's
monotonic sequence guarantee applies to runtime apply/recovery/rollback, not to monotonic sequence guarantee applies to runtime apply/recovery/rollback, not to
@@ -37,7 +47,8 @@ hydra-system restore --root-uuid ROOT_UUID --checkpoint CHECKPOINT_ID \
--execute --confirm-root-uuid ROOT_UUID --execute --confirm-root-uuid ROOT_UUID
``` ```
Plans and list mount targets read-only; Btrfs inspection disables log replay. Plans and list mount targets read-only; Btrfs inspection disables log replay with
`rescue=nologreplay`, as supported by the packaged kernel.
Execution requires matching confirmation and verifies UUID/PARTUUID uniqueness, Execution requires matching confirmation and verifies UUID/PARTUUID uniqueness,
ordinary partitions, inactive swap, no holders, and a single-device Btrfs layout. ordinary partitions, inactive swap, no holders, and a single-device Btrfs layout.
A private mount namespace and a root-owned lock isolate the command's mounts. A private mount namespace and a root-owned lock isolate the command's mounts.