Re: [pve-devel] [PATCH v4 container 8/9] api: move-volume: add move to another container

[Aaron Lauterer <a.lauterer@proxmox.com>]

Please wait a bit reviewing this patch. I did send it a bit too early as there are a few things not yet fully done. Especially being able to move unused volume or to move a volume from mpX to an unusedX volume on the target container.
Additionally we probably should not allow the rootfs to be moved as that will lead to som unexpected behaviors because AFAICT we never deal with a container missing a rootfs anywhere in our code.

On 11/2/21 16:03, Aaron Lauterer wrote:
> The goal of this is to expand the move-volume API endpoint to make it
> possible to move a container volume / mountpoint to another container.
> 
> Currently it works for regular mountpoints though it would be nice to be
> able to do it for unused mounpoints as well.
> 
> Signed-off-by: Aaron Lauterer <a.lauterer@proxmox.com>
> ---
> This is mostly the code from qemu-server with some adaptions. Mainly
> error messages and some checks.
> 
> Previous checks have been moved to '$move_to_storage_checks'.
> 
> v3 -> v4:
> * add check to avoid potential undefined warning in $vmlist->{$vmid}
> * add check if volume is part of a snapshot
> * removed line bloat
> 
> v2 -> v3:
> * mention default volume key in description
> * use $rpcenv->warn should replication snapshot removal fail
>      * also print the original error
> * code style things
> 
> v1 -> v2:
> * change --target-mp to --target-volume
> * make --target-volume optional and fallback to source mount point
> * use parse_volname instead of custom regex
> * adapt to find_free_volname
> * print warnings from update_pct_config
> * move running check back in both lock_config sections
> * fixed a few style issues
> 
> rfc -> v1:
> * add check if target guest is replicated and fail if the moved volume
>    does not support it
> * check if source volume has a format suffix and pass it to
>    'find_free_disk' or if the prefix is vm/subvol as those also have
>    their own meaning, see the comment in the code
> * fixed some style nits
>   src/PVE/API2/LXC.pm | 253 ++++++++++++++++++++++++++++++++++++++++----
>   1 file changed, 232 insertions(+), 21 deletions(-)
> 
> diff --git a/src/PVE/API2/LXC.pm b/src/PVE/API2/LXC.pm
> index 69df366..afc16d7 100644
> --- a/src/PVE/API2/LXC.pm
> +++ b/src/PVE/API2/LXC.pm
> @@ -1813,10 +1813,12 @@ __PACKAGE__->register_method({
>       method => 'POST',
>       protected => 1,
>       proxyto => 'node',
> -    description => "Move a rootfs-/mp-volume to a different storage",
> +    description => "Move a rootfs-/mp-volume to a different storage or to a different container.",
>       permissions => {
>   	description => "You need 'VM.Config.Disk' permissions on /vms/{vmid}, " .
> -	    "and 'Datastore.AllocateSpace' permissions on the storage.",
> +	    "and 'Datastore.AllocateSpace' permissions on the storage. To move ".
> +	    "a volume to another container, you need the permissions on the ".
> +	    "target container as well.",
>   	check =>
>   	[ 'and',
>   	  ['perm', '/vms/{vmid}', [ 'VM.Config.Disk' ]],
> @@ -1828,14 +1830,20 @@ __PACKAGE__->register_method({
>   	properties => {
>   	    node => get_standard_option('pve-node'),
>   	    vmid => get_standard_option('pve-vmid', { completion => \&PVE::LXC::complete_ctid }),
> +	    'target-vmid' => get_standard_option('pve-vmid', {
> +		completion => \&PVE::LXC::complete_ctid,
> +		optional => 1,
> +	    }),
>   	    volume => {
>   		type => 'string',
> +		#TODO: check how to handle unused mount points as the mp parameter is not configured
>   		enum => [ PVE::LXC::Config->valid_volume_keys() ],
>   		description => "Volume which will be moved.",
>   	    },
>   	    storage => get_standard_option('pve-storage-id', {
>   		description => "Target Storage.",
>   		completion => \&PVE::Storage::complete_storage_enabled,
> +		optional => 1,
>   	    }),
>   	    delete => {
>   		type => 'boolean',
> @@ -1856,6 +1864,21 @@ __PACKAGE__->register_method({
>   		minimum => '0',
>   		default => 'clone limit from datacenter or storage config',
>   	    },
> +	    'target-volume' => {
> +	        type => 'string',
> +		description => "The config key the volume will be moved to. Default is the " .
> +		    "source volume key.",
> +		enum => [PVE::LXC::Config->valid_volume_keys()],
> +		optional => 1,
> +	    },
> +	    'target-digest' => {
> +		type => 'string',
> +		description => 'Prevent changes if current configuration file of the target " .
> +		    "container has a different SHA1 digest. This can be used to prevent " .
> +		    "concurrent modifications.',
> +		maxLength => 40,
> +		optional => 1,
> +	    },
>   	},
>       },
>       returns => {
> @@ -1870,32 +1893,48 @@ __PACKAGE__->register_method({
>   
>   	my $vmid = extract_param($param, 'vmid');
>   
> +	my $target_vmid = extract_param($param, 'target-vmid');
> +
>   	my $storage = extract_param($param, 'storage');
>   
>   	my $mpkey = extract_param($param, 'volume');
>   
> +	my $target_mpkey = extract_param($param, 'target-volume') // $mpkey;
> +
> +	my $digest = extract_param($param, 'digest');
> +
> +	my $target_digest = extract_param($param, 'target-digest');
> +
>   	my $lockname = 'disk';
>   
>   	my ($mpdata, $old_volid);
>   
> -	PVE::LXC::Config->lock_config($vmid, sub {
> -	    my $conf = PVE::LXC::Config->load_config($vmid);
> -	    PVE::LXC::Config->check_lock($conf);
> +	die "either set storage or target-vmid, but not both\n"
> +	    if $storage && $target_vmid;
>   
> -	    die "cannot move volumes of a running container\n" if PVE::LXC::check_running($vmid);
> +	my $storecfg = PVE::Storage::config();
> +	my $source_volid;
>   
> -	    $mpdata = PVE::LXC::Config->parse_volume($mpkey, $conf->{$mpkey});
> -	    $old_volid = $mpdata->{volume};
> +	my $move_to_storage_checks = sub {
> +	    PVE::LXC::Config->lock_config($vmid, sub {
> +		my $conf = PVE::LXC::Config->load_config($vmid);
> +		PVE::LXC::Config->check_lock($conf);
>   
> -	    die "you can't move a volume with snapshots and delete the source\n"
> -		if $param->{delete} && PVE::LXC::Config->is_volume_in_use_by_snapshots($conf, $old_volid);
> +		die "cannot move volumes of a running container\n" if PVE::LXC::check_running($vmid);
>   
> -	    PVE::Tools::assert_if_modified($param->{digest}, $conf->{digest});
> +		$mpdata = PVE::LXC::Config->parse_volume($mpkey, $conf->{$mpkey});
> +		$old_volid = $mpdata->{volume};
>   
> -	    PVE::LXC::Config->set_lock($vmid, $lockname);
> -	});
> +		die "you can't move a volume with snapshots and delete the source\n"
> +		    if $param->{delete} && PVE::LXC::Config->is_volume_in_use_by_snapshots($conf, $old_volid);
>   
> -	my $realcmd = sub {
> +		PVE::Tools::assert_if_modified($digest, $conf->{digest});
> +
> +		PVE::LXC::Config->set_lock($vmid, $lockname);
> +	    });
> +	};
> +
> +	my $storage_realcmd = sub {
>   	    eval {
>   		PVE::Cluster::log_msg('info', $authuser, "move volume CT $vmid: move --volume $mpkey --storage $storage");
>   
> @@ -1965,15 +2004,187 @@ __PACKAGE__->register_method({
>   	    warn $@ if $@;
>   	    die $err if $err;
>   	};
> -	my $task = eval {
> -	    $rpcenv->fork_worker('move_volume', $vmid, $authuser, $realcmd);
> +
> +	my $load_and_check_reassign_configs = sub {
> +	    my $vmlist = PVE::Cluster::get_vmlist()->{ids};
> +
> +	    die "could not find CT ${vmid}\n" if !exists($vmlist->{$vmid});
> +
> +	    die "Both containers need to be on the same node ($vmlist->{$vmid}->{node}) ".
> +		"but target continer is on $vmlist->{$target_vmid}->{node}.\n"
> +		if $vmlist->{$vmid}->{node} ne $vmlist->{$target_vmid}->{node};
> +
> +	    my $source_conf = PVE::LXC::Config->load_config($vmid);
> +	    PVE::LXC::Config->check_lock($source_conf);
> +	    my $target_conf = PVE::LXC::Config->load_config($target_vmid);
> +	    PVE::LXC::Config->check_lock($target_conf);
> +
> +	    die "Can't move volumes from or to template VMs\n"
> +		if ($source_conf->{template} || $target_conf->{template});
> +
> +	    if ($digest) {
> +		eval { PVE::Tools::assert_if_modified($digest, $source_conf->{digest}) };
> +		die "Container ${vmid}: $@" if $@;
> +	    }
> +
> +	    if ($target_digest) {
> +		eval { PVE::Tools::assert_if_modified($target_digest, $target_conf->{digest}) };
> +		die "Container ${target_vmid}: $@" if $@;
> +	    }
> +
> +	    die "volume '${mpkey}' for container '$vmid' does not exist\n"
> +		if !defined($source_conf->{$mpkey});
> +
> +	    die "Target volume key '${target_mpkey}' is already in use for container '$target_vmid'\n"
> +		if exists $target_conf->{$target_mpkey};
> +
> +	    my $drive = PVE::LXC::Config->parse_volume(
> +		$mpkey,
> +		$source_conf->{$mpkey},
> +	    );
> +
> +	    $source_volid = $drive->{volume};
> +
> +	    die "disk '${mpkey}' has no associated volume\n"
> +		if !$source_volid;
> +	    die "Cannot move volume used by a snapshot to another container\n"
> +		if PVE::LXC::Config->is_volume_in_use_by_snapshots($source_conf, $source_volid);
> +	    die "Storage does not support moving of this disk to another container\n"
> +		if !PVE::Storage::volume_has_feature($storecfg, 'rename', $source_volid);
> +	    die "Cannot move a bindmound or device mount to another container\n"
> +		if $drive->{type} ne "volume";
> +	    die "Cannot move volume to another container while the source container is running\n"
> +		if PVE::LXC::check_running($vmid) && $mpkey !~ m/^unused\d+$/;
> +
> +	    my $repl_conf = PVE::ReplicationConfig->new();
> +	    my $is_replicated = $repl_conf->check_for_existing_jobs($target_vmid, 1);
> +	    my ($storeid, undef) = PVE::Storage::parse_volume_id($source_volid);
> +	    my $format = (PVE::Storage::parse_volname($storecfg, $source_volid))[6];
> +	    if (
> +		$is_replicated
> +		&& !PVE::Storage::storage_can_replicate($storecfg, $storeid, $format)
> +	    ) {
> +		die "Cannot move volume to a replicated container. Storage " .
> +		    "does not support replication!\n";
> +	    }
> +	    return ($source_conf, $target_conf);
>   	};
> -	if (my $err = $@) {
> -	    eval { PVE::LXC::Config->remove_lock($vmid, $lockname) };
> -	    warn $@ if $@;
> -	    die $err;
> +
> +	my $logfunc = sub {
> +	    my ($msg) = @_;
> +	    print STDERR "$msg\n";
> +	};
> +
> +	my $volume_reassignfn = sub {
> +	    return PVE::LXC::Config->lock_config($vmid, sub {
> +		return PVE::LXC::Config->lock_config($target_vmid, sub {
> +		    my ($source_conf, $target_conf) = &$load_and_check_reassign_configs();
> +		    die "cannot move volumes of a running container\n"
> +			if PVE::LXC::check_running($vmid);
> +
> +		    my $drive_param = PVE::LXC::Config->parse_volume(
> +			$target_mpkey,
> +			$source_conf->{$mpkey},
> +		    );
> +
> +		    print "moving volume '$mpkey' from container '$vmid' to '$target_vmid'\n";
> +		    my ($storage, $source_volname) = PVE::Storage::parse_volume_id($source_volid);
> +
> +		    my $fmt = (PVE::Storage::parse_volname($storecfg, $source_volid))[6];
> +
> +		    my $target_volname = PVE::Storage::find_free_volname(
> +			$storecfg,
> +			$storage,
> +			$target_vmid,
> +			$fmt
> +		    );
> +
> +		    my $new_volid = PVE::Storage::rename_volume(
> +			$storecfg,
> +			$source_volid,
> +			$target_volname,
> +		    );
> +
> +		    $drive_param->{volume} = $new_volid;
> +
> +		    delete $source_conf->{$mpkey};
> +		    print "removing volume '${mpkey}' from container '${vmid}' config\n";
> +		    PVE::LXC::Config->write_config($vmid, $source_conf);
> +
> +		    my $drive_string = PVE::LXC::Config->print_volume($target_mpkey, $drive_param);
> +		    my $running = PVE::LXC::check_running($target_vmid);
> +		    my $param = { $target_mpkey => $drive_string };
> +
> +		    my $errors = PVE::LXC::Config->update_pct_config(
> +			    $target_vmid,
> +			    $target_conf,
> +			    $running,
> +			    $param
> +			);
> +
> +		    foreach my $key (keys %$errors) {
> +			$rpcenv->warn($errors->{$key});
> +		    }
> +
> +		    PVE::LXC::Config->write_config($target_vmid, $target_conf);
> +		    $target_conf = PVE::LXC::Config->load_config($target_vmid);
> +
> +		    PVE::LXC::update_lxc_config($target_vmid, $target_conf);
> +		    print "target container '$target_vmid' updated with '$target_mpkey'\n";
> +
> +		    # remove possible replication snapshots
> +		    if (PVE::Storage::volume_has_feature($storecfg,'replicate', $source_volid)) {
> +			eval {
> +			    PVE::Replication::prepare(
> +				$storecfg,
> +				[$new_volid],
> +				undef,
> +				1,
> +				undef,
> +				$logfunc,
> +			    )
> +			};
> +			if (my $err = $@) {
> +			    $rpcenv->warn("Failed to remove replication snapshots on volume ".
> +				"'${target_mpkey}'. Manual cleanup could be necessary. " .
> +				"Error: ${err}\n");
> +			}
> +		    }
> +		});
> +	    });
> +	};
> +
> +	if ($target_vmid) {
> +	    $rpcenv->check_vm_perm($authuser, $target_vmid, undef, ['VM.Config.Disk'])
> +		if $authuser ne 'root@pam';
> +
> +	    die "Moving a volume to the same container is not possible. Did you ".
> +		"mean to move the volume to a different storage?\n"
> +		if $vmid eq $target_vmid;
> +
> +	    &$load_and_check_reassign_configs();
> +	    return $rpcenv->fork_worker(
> +		'move_volume',
> +		"${vmid}-${mpkey}>${target_vmid}-${target_mpkey}",
> +		$authuser,
> +		$volume_reassignfn
> +	    );
> +	} elsif ($storage) {
> +	    &$move_to_storage_checks();
> +	    my $task = eval {
> +		$rpcenv->fork_worker('move_volume', $vmid, $authuser, $storage_realcmd);
> +	    };
> +	    if (my $err = $@) {
> +		eval { PVE::LXC::Config->remove_lock($vmid, $lockname) };
> +		warn $@ if $@;
> +		die $err;
> +	    }
> +	    return $task;
> +	} else {
> +	    die "Provide either a 'storage' to move the mount point to a ".
> +		"different storage or 'target-vmid' and 'target-mp' to move ".
> +		"the mount point to another container\n";
>   	}
> -	return $task;
>     }});
>   
>   __PACKAGE__->register_method({
>