[pve-devel] [PATCH installer v4 4/4] low-level: install: check for already-existing `rpool` on install

[Christoph Heiss]

.. much in the same manner as the detection for LVM works.

zpools can only be renamed by importing them with a new name, so
unfortunately the import-export dance is needed.

Signed-off-by: Christoph Heiss <c.heiss at proxmox.com>
---
Changes v3 -> v4:
  * rename $response_ok -> $do_rename for clarity in

Changes v2 -> v3:
  * automatically rename existing rpools on auto-installs too

Changes v1 -> v2:
  * use unique pool id for renaming instead of generating random id
    ourselves
  * moved renaming functionality to own subroutine in new
    Proxmox::Sys::ZFS module

 Proxmox/Install.pm | 33 +++++++++++++++++++++++++++++++++
 Proxmox/Sys/ZFS.pm | 20 ++++++++++++++++++--
 2 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/Proxmox/Install.pm b/Proxmox/Install.pm
index 9efa4f1..19fd88d 100644
--- a/Proxmox/Install.pm
+++ b/Proxmox/Install.pm
@@ -16,6 +16,7 @@ use Proxmox::Install::StorageConfig;
 use Proxmox::Sys::Block qw(get_cached_disks wipe_disk partition_bootable_disk);
 use Proxmox::Sys::Command qw(run_command syscmd);
 use Proxmox::Sys::File qw(file_read_firstline file_write_all);
+use Proxmox::Sys::ZFS;
 use Proxmox::UI;
 
 # TODO: move somewhere better?
@@ -169,9 +170,41 @@ sub btrfs_create {
     syscmd($cmd);
 }
 
+sub zfs_ask_existing_zpool_rename {
+    my ($pool_name) = @_;
+
+    # At this point, no pools should be imported/active
+    my $exported_pools = Proxmox::Sys::ZFS::get_exported_pools();
+
+    foreach (@$exported_pools) {
+	next if $_->{name} ne $pool_name || $_->{state} ne 'ONLINE';
+	my $renamed_pool = "$_->{name}-OLD-$_->{id}";
+
+	my $do_rename = Proxmox::Install::Config::get_existing_storage_auto_rename();
+	if (!$do_rename) {
+	    $do_rename = Proxmox::UI::prompt(
+		"A ZFS pool named '$_->{name}' (id $_->{id}) already exists on the system.\n\n" .
+		"Do you want to rename the pool to '$renamed_pool' before continuing " .
+		"or cancel the installation?"
+	    );
+	}
+
+	# Import the pool using its id, as that is unique and works even if there are
+	# multiple zpools with the same name.
+	if ($do_rename) {
+	    Proxmox::Sys::ZFS::rename_pool($_->{id}, $renamed_pool);
+	} else {
+	    warn "Canceled installation as requested by user, due to already existing ZFS pool '$pool_name'\n";
+	    die "\n"; # causes abort without re-showing an error dialogue
+	}
+    }
+}
+
 sub zfs_create_rpool {
     my ($vdev, $pool_name, $root_volume_name) = @_;
 
+    zfs_ask_existing_zpool_rename($pool_name);
+
     my $iso_env = Proxmox::Install::ISOEnv::get();
 
     my $zfs_opts = Proxmox::Install::Config::get_zfs_opt();
diff --git a/Proxmox/Sys/ZFS.pm b/Proxmox/Sys/ZFS.pm
index 9232d1a..c5a807e 100644
--- a/Proxmox/Sys/ZFS.pm
+++ b/Proxmox/Sys/ZFS.pm
@@ -3,10 +3,10 @@ package Proxmox::Sys::ZFS;
 use strict;
 use warnings;
 
-use Proxmox::Sys::Command qw(run_command);
+use Proxmox::Sys::Command qw(run_command syscmd);
 
 use base qw(Exporter);
-our @EXPORT_OK = qw(get_exported_pools);
+our @EXPORT_OK = qw(get_exported_pools rename_pool);
 
 # Parses the output of running `zpool import`, which shows all importable
 # ZFS pools.
@@ -90,4 +90,20 @@ sub get_exported_pools {
     return zpool_import_parse_output($fh);
 }
 
+# Renames a importable ZFS pool by importing it with a new name and then
+# exporting again.
+#
+# Arguments:
+#
+# $poolid - Unique, numeric identifier of the pool to rename
+# $new_name - New name for the pool
+sub rename_pool {
+    my ($poolid, $new_name) = @_;
+
+    syscmd("zpool import -f $poolid $new_name") == 0 ||
+	die "failed to import zfs pool with id '$poolid' with new name '$new_name'\n";
+    syscmd("zpool export $new_name") == 0 ||
+	warn "failed to export renamed zfs pool '$new_name'\n";
+}
+
 1;
-- 
2.45.1