[pve-devel] [PATCH series v1 0/5] disk reassign: add new feature

[pve-devel] [PATCH series v1 0/5] disk reassign: add new feature

[Aaron Lauterer]

This RFC series implements a new feature which allows users to easily
reassign disks between VMs. Currently this is only possible with one of
the following manual steps:

* rename the disk image/file and do a `qm rescan`
* configure the disk manually and use the old image name, having an
    image for VM A assigned to VM B

The latter can cause unexpected behavior because PVE expects that the
VMID in a disk name always corresponds to the VM it is assigned to. Thus
when a disk, original from VM A was manually configured as disk for VM B
it happens that, when deleting VM A, the disk in question will be
deleted as well because it still had the VMID of VM A in it's name.

To issue a reassign from the CLI run:

qm reassign_disk <source VMID> <target VMID> <disk key>

where <disk key> is the config key of the disk, e.g. ide0, scsi1 and so
on.

The following storage types are implemented at the moment:
* dir based ones
    * directory
    * NFS
    * CIFS
* ZFS
* (thin) LVM
* Ceph RBD

Changes from RFC -> V1:
* support to reassign unused disks
* digest for target vm config
* reorder the checks a bit
* adding another one to check if the given key for the disk even exists
  in the config.


qemu-server: Aaron Lauterer (2):
  disk reassign: add API endpoint
  cli: disk reassign: add reassign_disk to qm command

 PVE/API2/Qemu.pm        | 106 ++++++++++++++++++++++++++++++++++++++++
 PVE/CLI/qm.pm           |   2 +
 PVE/QemuServer/Drive.pm |   4 ++
 3 files changed, 112 insertions(+)


storage: Aaron Lauterer (2):
  add disk reassign feature
  disk reassign: add not implemented yet message to storages

 PVE/Storage.pm                   | 10 ++++++++++
 PVE/Storage/CephFSPlugin.pm      |  5 +++++
 PVE/Storage/DRBDPlugin.pm        |  5 +++++
 PVE/Storage/GlusterfsPlugin.pm   |  5 +++++
 PVE/Storage/ISCSIDirectPlugin.pm |  5 +++++
 PVE/Storage/ISCSIPlugin.pm       |  4 ++++
 PVE/Storage/LVMPlugin.pm         | 15 +++++++++++++++
 PVE/Storage/Plugin.pm            | 21 +++++++++++++++++++++
 PVE/Storage/RBDPlugin.pm         | 13 +++++++++++++
 PVE/Storage/ZFSPlugin.pm         |  5 +++++
 PVE/Storage/ZFSPoolPlugin.pm     |  9 +++++++++
 11 files changed, 97 insertions(+)


widget-toolkit: Aaron Lauterer (1):
  utils: task_desc_table: add qmreassign

 src/Utils.js | 1 +
 1 file changed, 1 insertion(+)

-- 
2.20.1

[pve-devel] [PATCH qemu-server v1 1/5] disk reassign: add API endpoint

[Aaron Lauterer]

The goal of this new API endpoint is to provide an easy way to move a
disk between VMs as this was only possible with manual intervention
until now. Either by renaming the VM disk or by manually adding the
disks volid to the config of the other VM.

The latter can easily cause unexpected behavior such as disks attached
to VM B would be deleted if it used to be a disk of VM A. This happens
because PVE assumes that the VMID in the volname always matches the VM
the disk is attached to and thus, would remove any disk with VMID A
when VM A was deleted.

The term `reassign` was chosen as it is not yet used
for disk VMs.

Signed-off-by: Aaron Lauterer <a.lauterer@proxmox.com>
---

rfc -> v1:
* add support to reassign unused disks
* add support to provide a config digest for the target vm
* add additional check if disk key is present in config
* reorder checks a bit

In order to support unused disk I had to extend
PVE::QemuServer::Drive::valid_drive_names for the API parameter
validation.

Checks are ordered so that cheap tests are run at the first chance to
fail early.

The check if both VMs are present on the node is a bit redundant because
locking the config files will fail if the VM is not present. But with
the additional check we can provide a useful error message to the user
instead of a "Configuration file xyz does not exist" error.

Feedback, especially on the checks is welcome.


 PVE/API2/Qemu.pm        | 106 ++++++++++++++++++++++++++++++++++++++++
 PVE/QemuServer/Drive.pm |   4 ++
 2 files changed, 110 insertions(+)

diff --git a/PVE/API2/Qemu.pm b/PVE/API2/Qemu.pm
index 8da616a..533f01c 100644
--- a/PVE/API2/Qemu.pm
+++ b/PVE/API2/Qemu.pm
@@ -4265,4 +4265,110 @@ __PACKAGE__->register_method({
 	return PVE::QemuServer::Cloudinit::dump_cloudinit_config($conf, $param->{vmid}, $param->{type});
     }});
 
+__PACKAGE__->register_method({
+    name => 'reassign_vm_disk',
+    path => '{vmid}/reassign_disk',
+    method => 'POST',
+    protected => 1,
+    proxyto => 'node',
+    description => "Reassign a disk to another VM",
+    permissions => {
+	description => "You need 'VM.Config.Disk' permissions on /vms/{vmid}, and 'Datastore.Allocate' permissions on the storage.",
+	check => [ 'and',
+		   ['perm', '/vms/{vmid}', [ 'VM.Config.Disk' ]],
+		   ['perm', '/storage/{storage}', [ 'Datastore.Allocate' ]],
+	    ],
+    },
+    parameters => {
+        additionalProperties => 0,
+	properties => {
+	    node => get_standard_option('pve-node'),
+	    vmid => get_standard_option('pve-vmid', { completion => \&PVE::QemuServer::complete_vmid }),
+	    target_vmid => get_standard_option('pve-vmid', { completion => \&PVE::QemuServer::complete_vmid }),
+	    disk => {
+	        type => 'string',
+		description => "The config key of the disk to move (for example, ide0 or scsi1).",
+		enum => [PVE::QemuServer::Drive::valid_drive_names_with_unused()],
+	    },
+	    digest => {
+		type => 'string',
+		description => 'Prevent changes if current the configuration file of the source VM has a different SHA1 digest. This can be used to prevent concurrent modifications.',
+		maxLength => 40,
+		optional => 1,
+	    },
+	    target_digest => {
+		type => 'string',
+		description => 'Prevent changes if current the configuration file of the target VM has a different SHA1 digest. This can be used to prevent concurrent modifications.',
+		maxLength => 40,
+		optional => 1,
+	    },
+	},
+    },
+    returns => {
+	type => 'string',
+	description => "the task ID.",
+    },
+    code => sub {
+	my ($param) = @_;
+
+	my $rpcenv = PVE::RPCEnvironment::get();
+	my $authuser = $rpcenv->get_user();
+
+	my $node = extract_param($param, 'node');
+	my $vmid = extract_param($param, 'vmid');
+	my $target_vmid = extract_param($param, 'target_vmid');
+	my $digest = extract_param($param, 'digest');
+	my $target_digest = extract_param($param, 'target_digest');
+	my $disk = extract_param($param, 'disk');
+
+	my $storecfg = PVE::Storage::config();
+
+	die "You cannot reassign a disk to the same VM\n"
+	    if $vmid eq $target_vmid;
+
+	my $vmlist = PVE::QemuServer::vzlist();
+	die "Both VMs need to be on the same node\n"
+	    if !$vmlist->{$vmid}->{exists} || !$vmlist->{$target_vmid}->{exists};
+
+	return PVE::QemuConfig->lock_config($vmid, sub {
+	    my $conf = PVE::QemuConfig->load_config($vmid);
+	    PVE::QemuConfig->check_lock($conf);
+
+	    die "Source VM config checksum missmatch (file change by other user?)\n"
+		if $digest && $digest ne $conf->{digest};
+
+	    die "Disk '${disk}' does not exist\n"
+		if !exists($conf->{$disk});
+
+	    my $drive = PVE::QemuServer::parse_drive($disk, $conf->{$disk});
+	    die "disk '$disk' has no associated volume\n" if !$drive->{file};
+	    die "Cannot reassign a cdrom drive\n" if PVE::QemuServer::drive_is_cdrom($drive, 1);
+
+	    die "Cannot reassign disk while the source VM is running\n"
+		if PVE::QemuServer::check_running($vmid) && $disk !~ m/unused[0-9]/;
+
+	    return PVE::QemuConfig->lock_config($target_vmid, sub {
+		my $target_conf = PVE::QemuConfig->load_config($target_vmid);
+		PVE::QemuConfig->check_lock($target_conf);
+
+		die "Target VM config checksum missmatch (file change by other user?)\n"
+		    if $target_digest && $target_digest ne $target_conf->{digest};
+
+		PVE::Cluster::log_msg('info', $authuser, "reassign disk VM $vmid: reassign --disk $disk --target_vmid $target_vmid");
+
+		my $realcmd = sub {
+		    my $new_volid = PVE::Storage::reassign_volume($storecfg, $drive->{file}, $target_vmid);
+
+		    delete $conf->{$disk};
+		    PVE::QemuConfig->write_config($vmid, $conf);
+
+		    PVE::QemuConfig->add_unused_volume($target_conf, $new_volid);
+		    PVE::QemuConfig->write_config($target_vmid, $target_conf);
+		};
+
+		return $rpcenv->fork_worker('qmreassign', $vmid, $authuser, $realcmd);
+	    });
+	});
+    }});
+
 1;
diff --git a/PVE/QemuServer/Drive.pm b/PVE/QemuServer/Drive.pm
index 91c33f8..d2f59cd 100644
--- a/PVE/QemuServer/Drive.pm
+++ b/PVE/QemuServer/Drive.pm
@@ -383,6 +383,10 @@ sub valid_drive_names {
             'efidisk0');
 }
 
+sub valid_drive_names_with_unused {
+    return (valid_drive_names(), map {"unused$_"} (0 .. ($MAX_UNUSED_DISKS -1)));
+}
+
 sub is_valid_drivename {
     my $dev = shift;
 
-- 
2.20.1

[pve-devel] [PATCH qemu-server v1 2/5] cli: disk reassign: add reassign_disk to qm command

[Aaron Lauterer]

Signed-off-by: Aaron Lauterer <a.lauterer@proxmox.com>
---
rfc -> v1: nothing changed

 PVE/CLI/qm.pm | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/PVE/CLI/qm.pm b/PVE/CLI/qm.pm
index 282fa86..c947884 100755
--- a/PVE/CLI/qm.pm
+++ b/PVE/CLI/qm.pm
@@ -913,6 +913,8 @@ our $cmddef = {
 
     move_disk => [ "PVE::API2::Qemu", 'move_vm_disk', ['vmid', 'disk', 'storage'], { node => $nodename }, $upid_exit ],
 
+    reassign_disk => [ "PVE::API2::Qemu", 'reassign_vm_disk', ['vmid', 'target_vmid', 'disk'], { node => $nodename } ],
+
     unlink => [ "PVE::API2::Qemu", 'unlink', ['vmid'], { node => $nodename } ],
 
     config => [ "PVE::API2::Qemu", 'vm_config', ['vmid'],
-- 
2.20.1

[pve-devel] [PATCH storage v1 3/5] add disk reassign feature

[Aaron Lauterer]

Functionality has been added for the following storage types:

* dir based ones
    * directory
    * NFS
    * CIFS
* ZFS
* (thin) LVM
* Ceph RBD

Signed-off-by: Aaron Lauterer <a.lauterer@proxmox.com>
---

rfc -> v1: nothing changed

 PVE/Storage.pm               | 10 ++++++++++
 PVE/Storage/LVMPlugin.pm     | 15 +++++++++++++++
 PVE/Storage/Plugin.pm        | 21 +++++++++++++++++++++
 PVE/Storage/RBDPlugin.pm     | 13 +++++++++++++
 PVE/Storage/ZFSPoolPlugin.pm |  9 +++++++++
 5 files changed, 68 insertions(+)

diff --git a/PVE/Storage.pm b/PVE/Storage.pm
index 4a60615..919c606 100755
--- a/PVE/Storage.pm
+++ b/PVE/Storage.pm
@@ -1759,6 +1759,16 @@ sub complete_volume {
     return $res;
 }
 
+sub reassign_volume {
+    my ($cfg, $volid, $target_vmid) = @_;
+
+    my ($storeid, $volname) = parse_volume_id($volid);
+    my $scfg = storage_config($cfg, $storeid);
+    my $plugin = PVE::Storage::Plugin->lookup($scfg->{type});
+
+    return $plugin->reassign_volume($scfg, $storeid, $volname, $target_vmid);
+}
+
 # Various io-heavy operations require io/bandwidth limits which can be
 # configured on multiple levels: The global defaults in datacenter.cfg, and
 # per-storage overrides. When we want to do a restore from storage A to storage
diff --git a/PVE/Storage/LVMPlugin.pm b/PVE/Storage/LVMPlugin.pm
index c0740d4..28ff6c8 100644
--- a/PVE/Storage/LVMPlugin.pm
+++ b/PVE/Storage/LVMPlugin.pm
@@ -337,6 +337,13 @@ sub lvcreate {
     run_command($cmd, errmsg => "lvcreate '$vg/$name' error");
 }
 
+sub lvrename {
+    my ($vg, $oldname, $newname) = @_;
+
+    my $cmd = ['/sbin/lvrename', $vg, $oldname, $newname];
+    run_command($cmd, errmsg => "lvrename '${vg}/${oldname}' to '${newname}' error");
+}
+
 sub alloc_image {
     my ($class, $storeid, $scfg, $vmid, $fmt, $name, $size) = @_;
 
@@ -681,4 +688,12 @@ sub volume_import_write {
 	input => '<&'.fileno($input_fh));
 }
 
+sub reassign_volume {
+    my ($class, $scfg, $storeid, $volname, $target_vmid) = @_;
+
+    my $target_volname = $class->find_free_diskname($storeid, $scfg, $target_vmid);
+    lvrename($scfg->{vgname}, $volname, $target_volname);
+    return "${storeid}:${target_volname}";
+}
+
 1;
diff --git a/PVE/Storage/Plugin.pm b/PVE/Storage/Plugin.pm
index 8a58ff4..770a482 100644
--- a/PVE/Storage/Plugin.pm
+++ b/PVE/Storage/Plugin.pm
@@ -1411,4 +1411,25 @@ sub volume_import_formats {
     return ();
 }
 
+sub reassign_volume {
+    my ($class, $scfg, $storeid, $volname, $target_vmid) = @_;
+
+    my $basedir = $class->get_subdir($scfg, 'images');
+    my $imagedir = "${basedir}/${target_vmid}";
+
+    mkpath $imagedir;
+
+    my @parsed_volname = $class->parse_volname($volname);
+    my $format = $parsed_volname[6];
+    my $target_volname = $class->find_free_diskname($storeid, $scfg, $target_vmid, $format, 1);
+
+    my $old_path = "${basedir}/${volname}";
+    my $new_path = "${imagedir}/${target_volname}";
+
+    rename($old_path, $new_path) ||
+	die "rename '$old_path' to '$new_path' failed - $!\n";
+
+    return "${storeid}:${target_vmid}/${target_volname}";
+}
+
 1;
diff --git a/PVE/Storage/RBDPlugin.pm b/PVE/Storage/RBDPlugin.pm
index 38f2b46..c0bd74c 100644
--- a/PVE/Storage/RBDPlugin.pm
+++ b/PVE/Storage/RBDPlugin.pm
@@ -719,4 +719,17 @@ sub volume_has_feature {
     return undef;
 }
 
+sub reassign_volume {
+    my ($class, $scfg, $storeid, $volname, $target_vmid) = @_;
+
+    my $target_volname = $class->find_free_diskname($storeid, $scfg, $target_vmid);
+    my $cmd = $rbd_cmd->($scfg, $storeid, 'rename', $volname, $target_volname);
+
+    run_rbd_command(
+	$cmd,
+	errmsg => "could not rename image '$volname' to '$target_volname'",
+    );
+    return "${storeid}:${target_volname}";
+}
+
 1;
diff --git a/PVE/Storage/ZFSPoolPlugin.pm b/PVE/Storage/ZFSPoolPlugin.pm
index 10354b3..5baa5c2 100644
--- a/PVE/Storage/ZFSPoolPlugin.pm
+++ b/PVE/Storage/ZFSPoolPlugin.pm
@@ -749,4 +749,13 @@ sub volume_import_formats {
     return $class->volume_export_formats($scfg, $storeid, $volname, undef, $base_snapshot, $with_snapshots);
 }
 
+sub reassign_volume {
+    my ($class, $scfg, $storeid, $volname, $target_vmid) = @_;
+
+    my $target_volname = $class->find_free_diskname($storeid, $scfg, $target_vmid);
+    $class->zfs_request($scfg, 5, 'rename', "$scfg->{pool}/$volname", "$scfg->{pool}/$target_volname");
+
+    return "${storeid}:${target_volname}";
+}
+
 1;
-- 
2.20.1

[pve-devel] [PATCH storage v1 4/5] disk reassign: add not implemented yet message to storages

[Aaron Lauterer]

Signed-off-by: Aaron Lauterer <a.lauterer@proxmox.com>
---
rfc -> v1: nothing changed

 PVE/Storage/CephFSPlugin.pm      | 5 +++++
 PVE/Storage/DRBDPlugin.pm        | 5 +++++
 PVE/Storage/GlusterfsPlugin.pm   | 5 +++++
 PVE/Storage/ISCSIDirectPlugin.pm | 5 +++++
 PVE/Storage/ISCSIPlugin.pm       | 4 ++++
 PVE/Storage/ZFSPlugin.pm         | 5 +++++
 6 files changed, 29 insertions(+)

diff --git a/PVE/Storage/CephFSPlugin.pm b/PVE/Storage/CephFSPlugin.pm
index 880ec05..ba31366 100644
--- a/PVE/Storage/CephFSPlugin.pm
+++ b/PVE/Storage/CephFSPlugin.pm
@@ -222,4 +222,9 @@ sub deactivate_storage {
     }
 }
 
+sub reassign_volume {
+    my ($class, $scfg, $storeid, $volname, $target_vmid) = @_;
+    die "Not implemented for this storage type\n";
+}
+
 1;
diff --git a/PVE/Storage/DRBDPlugin.pm b/PVE/Storage/DRBDPlugin.pm
index dbae4d1..304ade7 100644
--- a/PVE/Storage/DRBDPlugin.pm
+++ b/PVE/Storage/DRBDPlugin.pm
@@ -404,4 +404,9 @@ sub volume_has_feature {
     return undef;
 }
 
+sub reassign_volume {
+    my ($class, $scfg, $storeid, $volname, $target_vmid) = @_;
+    die "Not implemented for this storage type\n";
+}
+
 1;
diff --git a/PVE/Storage/GlusterfsPlugin.pm b/PVE/Storage/GlusterfsPlugin.pm
index 2dd414d..831d2ef 100644
--- a/PVE/Storage/GlusterfsPlugin.pm
+++ b/PVE/Storage/GlusterfsPlugin.pm
@@ -348,4 +348,9 @@ sub check_connection {
     return defined($server) ? 1 : 0;
 }
 
+sub reassign_volume {
+    my ($class, $scfg, $storeid, $volname, $target_vmid) = @_;
+    die "Not implemented for this storage type\n";
+}
+
 1;
diff --git a/PVE/Storage/ISCSIDirectPlugin.pm b/PVE/Storage/ISCSIDirectPlugin.pm
index 9777969..8d72173 100644
--- a/PVE/Storage/ISCSIDirectPlugin.pm
+++ b/PVE/Storage/ISCSIDirectPlugin.pm
@@ -252,4 +252,9 @@ sub volume_has_feature {
     return undef;
 }
 
+sub reassign_volume {
+    my ($class, $scfg, $storeid, $volname, $target_vmid) = @_;
+    die "Not implemented for this storage type\n";
+}
+
 1;
diff --git a/PVE/Storage/ISCSIPlugin.pm b/PVE/Storage/ISCSIPlugin.pm
index f2694ba..602fb1d 100644
--- a/PVE/Storage/ISCSIPlugin.pm
+++ b/PVE/Storage/ISCSIPlugin.pm
@@ -438,5 +438,9 @@ sub volume_has_feature {
     return undef;
 }
 
+sub reassign_volume {
+    my ($class, $scfg, $storeid, $volname, $target_vmid) = @_;
+    die "Not implemented for this storage type\n";
+}
 
 1;
diff --git a/PVE/Storage/ZFSPlugin.pm b/PVE/Storage/ZFSPlugin.pm
index 383f0a0..4097b1a 100644
--- a/PVE/Storage/ZFSPlugin.pm
+++ b/PVE/Storage/ZFSPlugin.pm
@@ -421,4 +421,9 @@ sub deactivate_volume {
     return 1;
 }
 
+sub reassign_volume {
+    my ($class, $scfg, $storeid, $volname, $target_vmid) = @_;
+    die "Not implemented for this storage type\n";
+}
+
 1;
-- 
2.20.1

[pve-devel] [PATCH widget-toolkit v1 5/5] utils: task_desc_table: add qmreassign

[Aaron Lauterer]

Signed-off-by: Aaron Lauterer <a.lauterer@proxmox.com>
---
rfc -> v1: nothing changed

 src/Utils.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/Utils.js b/src/Utils.js
index 4be95b2..c022084 100644
--- a/src/Utils.js
+++ b/src/Utils.js
@@ -583,6 +583,7 @@ utilities: {
 	qmigrate: ['VM', gettext('Migrate')],
 	qmclone: ['VM', gettext('Clone')],
 	qmmove: ['VM', gettext('Move disk')],
+	qmreassign: ['VM', gettext('Reassign disk')],
 	qmtemplate: ['VM', gettext('Convert to template')],
 	qmstart: ['VM', gettext('Start')],
 	qmstop: ['VM', gettext('Stop')],
-- 
2.20.1