Re: [Libguestfs] [guestfs-tools PATCH] sysprep: remove lvm2's default "system.devices" file

(Background: lvm2 commit 83fe6e720f42, "device usage based on devices file", 2021-02-23; first released in v2_03_12.) "lvm pvscan" may be -- and in RHEL9, will soon be -- restricted to those block devices whose WWIDs are listed in "/etc/lvm/devices/system.devices". This is a problem when cloning a VM, as cloning may change the WWIDs of the domain's disk devices, and then physical volumes underlying the guest filesystems may not be found. Example: <https://bugzilla.redhat.com/show_bug.cgi?id=2059545#c12>;. Add the "lvm-system-devices" operation for removing this file, so that "lvm pvscan" investigate all block devices for PVs. (Note that this operation is independent from "lvm-uuids". The libguestfs appliance creates a pristine LVM_SYSTEM_DIR in "appliance/init" (see libguestfs commit dd162d2cd56a), thus, when "lvm-uuids" calls "g#pvs" and "g#vgs", those APIs can never be affected by an "$LVM_SYSTEM_DIR/devices/system.devices" file.) Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2072493 Signed-off-by: Laszlo Ersek <lersek(a)redhat.com&gt; --- sysprep/Makefile.am | 1 + sysprep/sysprep_operation_lvm_system_devices.ml | 44 ++++++++++++++++++++ 2 files changed, 45 insertions(+) diff --git a/sysprep/Makefile.am b/sysprep/Makefile.am index 0e3afc8a01c7..7d5e8aadf448 100644 --- a/sysprep/Makefile.am +++ b/sysprep/Makefile.am @@ -46,6 +46,7 @@ operations = \ ipa_client \ kerberos_data \ kerberos_hostkeytab \ + lvm_system_devices \ lvm_uuids \ logfiles \ machine_id \ diff --git a/sysprep/sysprep_operation_lvm_system_devices.ml b/sysprep/sysprep_operation_lvm_system_devices.ml new file mode 100644 index 000000000000..b41fa5dbc23a --- /dev/null +++ b/sysprep/sysprep_operation_lvm_system_devices.ml @@ -0,0 +1,44 @@ +(* virt-sysprep + * Copyright (C) 2012-2022 Red Hat Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + *) + +open Sysprep_operation +open Common_gettext.Gettext + +module G = Guestfs + +let system_devices_file = "/etc/lvm/devices/system.devices" + +let rec lvm_system_devices_perform g root side_effects = + let typ = g#inspect_get_type root in + if typ = "linux" then g#rm_f system_devices_file + +let op = { + defaults with + name = "lvm-system-devices"; + enabled_by_default = true; + heading = s_"Remove LVM2 system.devices file"; + pod_description = + Some (s_"On Linux guests, LVM2's scanning for physical volumes (PVs) may \ + be restricted to those block devices whose WWIDs are listed in \ + C<" ^ system_devices_file ^ ">. When cloning VMs, WWIDs may \ + change, breaking C<lvm pvscan>. Remove \ + C<" ^ system_devices_file ^ ">."); + perform_on_filesystems = Some lvm_system_devices_perform; +} + +let () = register_operation op