[pve-devel] [PATCH v2 qemu-server 07/11] cfg2cmd: allow PBS snapshots as backing files for drives
Stefan Reiter
s.reiter at proxmox.com
Wed Mar 3 10:56:08 CET 2021
Uses the custom 'alloc-track' filter node to redirect writes to the
original drives target, while unwritten blocks will be read from the
specified PBS snapshot.
Signed-off-by: Stefan Reiter <s.reiter at proxmox.com>
---
v2:
* build logic directly into print_drive_commandline_full, instead of string
replacements in config_to_command
* support "rbd:" storage paths as target
PVE/QemuServer.pm | 77 +++++++++++++++++++++++++++++++++++++++--------
1 file changed, 65 insertions(+), 12 deletions(-)
diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 0c39a6b..22edc2a 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -1514,28 +1514,31 @@ sub get_initiator_name {
}
sub print_drive_commandline_full {
- my ($storecfg, $vmid, $drive) = @_;
+ my ($storecfg, $vmid, $drive, $pbs_name) = @_;
my $path;
my $volid = $drive->{file};
- my $format;
+ my $format = $drive->{format};
if (drive_is_cdrom($drive)) {
$path = get_iso_path($storecfg, $vmid, $volid);
+ die "cannot back cdrom drive with PBS snapshot\n" if $pbs_name;
} else {
my ($storeid, $volname) = PVE::Storage::parse_volume_id($volid, 1);
if ($storeid) {
$path = PVE::Storage::path($storecfg, $volid);
my $scfg = PVE::Storage::storage_config($storecfg, $storeid);
- $format = qemu_img_format($scfg, $volname);
+ $format //= qemu_img_format($scfg, $volname);
} else {
$path = $volid;
- $format = "raw";
+ $format //= "raw";
}
}
+ my $is_rbd = $path =~ m/^rbd:/;
+
my $opts = '';
- my @qemu_drive_options = qw(heads secs cyls trans media format cache rerror werror aio discard);
+ my @qemu_drive_options = qw(heads secs cyls trans media cache rerror werror aio discard);
foreach my $o (@qemu_drive_options) {
$opts .= ",$o=$drive->{$o}" if defined($drive->{$o});
}
@@ -1568,7 +1571,13 @@ sub print_drive_commandline_full {
}
}
- $opts .= ",format=$format" if $format && !$drive->{format};
+ if ($pbs_name) {
+ $format = "rbd" if $is_rbd;
+ die "PBS backing requires a drive with known format\n" if !$format;
+ $opts .= ",format=alloc-track,file.driver=$format";
+ } elsif ($format) {
+ $opts .= ",format=$format";
+ }
my $cache_direct = 0;
@@ -1598,14 +1607,41 @@ sub print_drive_commandline_full {
# This used to be our default with discard not being specified:
$detectzeroes = 'on';
}
- $opts .= ",detect-zeroes=$detectzeroes" if $detectzeroes;
+
+ # note: 'detect-zeroes' works per blockdev and we want it to persist
+ # after the alloc-track is removed, so put it on 'file' directly
+ my $dz_param = $pbs_name ? "file.detect-zeroes" : "detect-zeroes";
+ $opts .= ",$dz_param=$detectzeroes" if $detectzeroes;
}
- my $pathinfo = $path ? "file=$path," : '';
+ if ($pbs_name) {
+ $opts .= ",backing=$pbs_name";
+ $opts .= ",auto-remove=on";
+ }
+
+ # my $file_param = $pbs_name ? "file.file.filename" : "file";
+ my $file_param = "file";
+ if ($pbs_name) {
+ # non-rbd drivers require the underlying file to be a seperate block
+ # node, so add a second .file indirection
+ $file_param .= ".file" if !$is_rbd;
+ $file_param .= ".filename";
+ }
+ my $pathinfo = $path ? "$file_param=$path," : '';
return "${pathinfo}if=none,id=drive-$drive->{interface}$drive->{index}$opts";
}
+sub print_pbs_blockdev {
+ my ($pbs_conf, $pbs_name) = @_;
+ my $blockdev = "driver=pbs,node-name=$pbs_name,read-only=on";
+ $blockdev .= ",repository=$pbs_conf->{repository}";
+ $blockdev .= ",snapshot=$pbs_conf->{snapshot}";
+ $blockdev .= ",archive=$pbs_conf->{archive}";
+ $blockdev .= ",keyfile=$pbs_conf->{keyfile}" if $pbs_conf->{keyfile};
+ return $blockdev;
+}
+
sub print_netdevice_full {
my ($vmid, $conf, $net, $netid, $bridges, $use_old_bios_files, $arch, $machine_type) = @_;
@@ -3023,7 +3059,8 @@ sub query_understood_cpu_flags {
}
sub config_to_command {
- my ($storecfg, $vmid, $conf, $defaults, $forcemachine, $forcecpu) = @_;
+ my ($storecfg, $vmid, $conf, $defaults, $forcemachine, $forcecpu,
+ $pbs_backing) = @_;
my $cmd = [];
my $globalFlags = [];
@@ -3519,7 +3556,14 @@ sub config_to_command {
$ahcicontroller->{$controller}=1;
}
- my $drive_cmd = print_drive_commandline_full($storecfg, $vmid, $drive);
+ my $pbs_conf = $pbs_backing->{$ds};
+ my $pbs_name = undef;
+ if ($pbs_conf) {
+ $pbs_name = "drive-$ds-pbs";
+ push @$devices, '-blockdev', print_pbs_blockdev($pbs_conf, $pbs_name);
+ }
+
+ my $drive_cmd = print_drive_commandline_full($storecfg, $vmid, $drive, $pbs_name);
$drive_cmd .= ',readonly' if PVE::QemuConfig->is_template($conf);
push @$devices, '-drive',$drive_cmd;
@@ -4923,6 +4967,15 @@ sub vm_start {
# timeout => in seconds
# paused => start VM in paused state (backup)
# resume => resume from hibernation
+# pbs-backing => {
+# sata0 => {
+# repository
+# snapshot
+# keyfile
+# archive
+# },
+# virtio2 => ...
+# }
# migrate_opts:
# nbd => volumes for NBD exports (vm_migrate_alloc_nbd_disks)
# migratedfrom => source node
@@ -4969,8 +5022,8 @@ sub vm_start_nolock {
print "Resuming suspended VM\n";
}
- my ($cmd, $vollist, $spice_port) =
- config_to_command($storecfg, $vmid, $conf, $defaults, $forcemachine, $forcecpu);
+ my ($cmd, $vollist, $spice_port) = config_to_command($storecfg, $vmid,
+ $conf, $defaults, $forcemachine, $forcecpu, $params->{'pbs-backing'});
my $migration_ip;
my $get_migration_ip = sub {
--
2.20.1
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