[pve-devel] [PATCH manager] fix #4631: ceph: osd: create: add osds-per-device

Aaron Lauterer a.lauterer at proxmox.com
Tue Apr 18 14:26:46 CEST 2023

Allows to automatically create multiple OSDs per physical device. The
main use case are fast NVME drives that would be bottlenecked by a
single OSD service.

By using the 'ceph-volume lvm batch' command instead of the 'ceph-volume
lvm create' for multiple OSDs / device, we don't have to deal with the
split of the drive ourselves.

But this means that the parameters to specify a DB or WAL device won't
work as the 'batch' command doesn't use them. Dedicated DB and WAL
devices don't make much sense anyway if we place the OSDs on fast NVME

Some other changes to how the command is built were needed as well, as
the 'batch' command needs the path to the disk as a positional argument,
not as '--data /dev/sdX'.
We drop the '--cluster-fsid' paramter because the 'batch' command
doesn't accept it. The 'create' will fall back to reading it from the
ceph.conf file.

Removal of OSDs works as expected without any code changes. As long as
there are other OSDs on a disk, the VG & PV won't be removed, even if
'cleanup' is enabled.

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

There are a few other places where we can improve the OSD handling if
multiple OSDs are on one physical disk.

* Disk overview in the Node -> Disks panel: show all OSD IDs present on
  the disk instead of the last one in the list that was parsed
* Create window: allow to select disks that already have OSDs on it,
    but still have free space available

These things will need additions and changes to the API. Especially for
the changes we probably want to target the Proxmox VE 8 release.

 PVE/API2/Ceph/OSD.pm | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/PVE/API2/Ceph/OSD.pm b/PVE/API2/Ceph/OSD.pm
index ded35990..43dad56b 100644
--- a/PVE/API2/Ceph/OSD.pm
+++ b/PVE/API2/Ceph/OSD.pm
@@ -275,6 +275,12 @@ __PACKAGE__->register_method ({
 		type => 'string',
 		description => "Set the device class of the OSD in crush."
+	    'osds-per-device' => {
+		optional => 1,
+		type => 'number',
+		minimum => '1',
+		description => 'OSD services per physical device. Can improve fast NVME utilization.',
+	    },
     returns => { type => 'string' },
@@ -294,6 +300,15 @@ __PACKAGE__->register_method ({
 	# extract parameter info and fail if a device is set more than once
 	my $devs = {};
+	# allow 'osds-per-device' only without dedicated db and/or wal devs. We cannot specify them with
+	# 'ceph-volume lvm batch' and they don't make a lot of sense on fast NVMEs anyway.
+	if ($param->{'osds-per-device'}) {
+	    for my $type ( qw(db_dev wal_dev) ) {
+		die "Cannot use 'osds-per-device' parameter with '${type}'"
+		    if $param->{$type};
+	    }
+	}
 	my $ceph_conf = cfs_read_file('ceph.conf');
 	my $osd_network = $ceph_conf->{global}->{cluster_network};
@@ -364,8 +379,6 @@ __PACKAGE__->register_method ({
 	my $monstat = $rados->mon_command({ prefix => 'quorum_status' });
 	die "unable to get fsid\n" if !$monstat->{monmap} || !$monstat->{monmap}->{fsid};
-	my $fsid = $monstat->{monmap}->{fsid};
-        $fsid = $1 if $fsid =~ m/^([0-9a-f\-]+)$/;
 	my $ceph_bootstrap_osd_keyring = PVE::Ceph::Tools::get_config('ceph_bootstrap_osd_keyring');
@@ -470,7 +483,10 @@ __PACKAGE__->register_method ({
 		my $dev_class = $param->{'crush-device-class'};
-		my $cmd = ['ceph-volume', 'lvm', 'create', '--cluster-fsid', $fsid ];
+		# create allows for detailed configuration of DB and WAL devices
+		# batch for easy creation of multiple OSDs (per device)
+		my $create_mode = $param->{'osds-per-device'} ? 'batch' : 'create';
+		my $cmd = ['ceph-volume', 'lvm', $create_mode ];
 		push @$cmd, '--crush-device-class', $dev_class if $dev_class;
 		my $devname = $devs->{dev}->{name};
@@ -504,8 +520,11 @@ __PACKAGE__->register_method ({
 		    push @$cmd, "--block.$type", $part_or_lv;
-		push @$cmd, '--data', $devpath;
+		push @$cmd, '--data' if $create_mode eq 'create';
+		push @$cmd, $devpath;
 		push @$cmd, '--dmcrypt' if $param->{encrypted};
+		push @$cmd, '--osds-per-device', $param->{'osds-per-device'}, '--yes'
+		    if $create_mode eq 'batch';

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