libvirt: remove glusterfs volume driver

Cinder deprecated the GlusterFS volume driver
in Newton and deleted it in Ocata:

I10c576602dd0e65947d1a1af5d04b8ada54f4625

Since it's unused, unmaintained and unsupported in
Cinder we should remove it from the libvirt driver.

This also removes the related configuration options.

A note is left in the code since I'm unsure if anything
relies on checking for the netfs disk source_protocol which
was added at the same time as the glusterfs support in
Ic6dd861b40b692b25df67c9d5b63fd436c690fde.

Change-Id: I2745f5578646ec994b53f6b5c0a5f62637b0948a

api-ref/source/os-assisted-volume-snapshots.inc

@@ -9,10 +9,10 @@ file format is supported.
 
 This API is only implemented by the libvirt compute driver.
 
-An internal snapshot that lacks storage such as NFS or GlusterFS can use
+An internal snapshot that lacks storage such as NFS can use
 an emulator/hypervisor to add the snapshot feature.
-This is used to enable snapshot of volumes on backends such as NFS or
-GlusterFS by storing data as qcow2 files on these volumes.
+This is used to enable snapshot of volumes on backends such as NFS
+by storing data as qcow2 files on these volumes.
 
 This API is only ever called by Cinder, where it is used to create a snapshot
 for drivers that extend the remotefs Cinder driver.

doc/source/support-matrix.ini

@@ -950,7 +950,7 @@ notes=Block storage provides instances with direct attached
   As an alternative to direct attached disks, an instance may
   choose to use network based persistent storage. OpenStack provides
   object storage via the Swift service, or a traditional filesystem
-  such as NFS/GlusterFS may be used. Some types of instances may
+  such as NFS may be used. Some types of instances may
   not require persistent storage at all, being simple transaction
   processing systems reading requests & sending results to and from
   the network. Therefore support for this configuration is not

nova/conf/libvirt.py

@@ -759,19 +759,6 @@
 ]
 
 libvirt_volume_opts = [
-    cfg.ListOpt('qemu_allowed_storage_drivers',
-                default=[],
-                help="""
-Protocols listed here will be accessed directly from QEMU.
-
-If gluster is present in qemu_allowed_storage_drivers, glusterfs's backend will
-pass a disk configuration to QEMU. This allows QEMU to access the volume using
-libgfapi rather than mounting GlusterFS via fuse.
-
-Possible values:
-
-* [gluster]
-"""),
     cfg.BoolOpt('volume_use_multipath',
                 default=False,
                 deprecated_name='iscsi_use_multipath',
@@ -801,15 +788,6 @@
 """)
 ]
 
-libvirt_volume_glusterfs_opts = [
-    cfg.StrOpt('glusterfs_mount_point_base',
-               default=paths.state_path_def('mnt'),
-               help="""
-Absolute path to the directory where the glusterfs volume is mounted on the
-compute node.
-""")
-]
-
 libvirt_volume_iscsi_opts = [
     cfg.StrOpt('iscsi_iface',
                deprecated_name='iscsi_transport',
@@ -1061,7 +1039,6 @@
     libvirt_vif_opts,
     libvirt_volume_opts,
     libvirt_volume_aoe_opts,
-    libvirt_volume_glusterfs_opts,
     libvirt_volume_iscsi_opts,
     libvirt_volume_iser_opts,
     libvirt_volume_net_opts,

nova/tests/unit/virt/libvirt/test_config.py

@@ -1127,12 +1127,12 @@ def test_config_file_parse(self):
     def test_config_network_parse(self):
         xml = """<backingStore type='network' index='1'>
                    <format type='qcow2'/>
-                   <source protocol='gluster' name='volume1/img1'>
+                   <source protocol='netfs' name='volume1/img1'>
                      <host name='host1' port='24007'/>
                    </source>
                    <backingStore type='network' index='2'>
                      <format type='qcow2'/>
-                     <source protocol='gluster' name='volume1/img2'>
+                     <source protocol='netfs' name='volume1/img2'>
                        <host name='host1' port='24007'/>
                      </source>
                      <backingStore/>
@@ -1145,7 +1145,7 @@ def test_config_network_parse(self):
         obj.parse_dom(xmldoc)
 
         self.assertEqual(obj.source_type, 'network')
-        self.assertEqual(obj.source_protocol, 'gluster')
+        self.assertEqual(obj.source_protocol, 'netfs')
         self.assertEqual(obj.source_name, 'volume1/img1')
         self.assertEqual(obj.source_hosts[0], 'host1')
         self.assertEqual(obj.source_ports[0], '24007')
@@ -2474,7 +2474,7 @@ def test_config_snapshot_with_network_disks(self):
         disk.source_type = 'network'
         disk.source_hosts = ['host1']
         disk.source_ports = ['12345']
-        disk.source_protocol = 'glusterfs'
+        disk.source_protocol = 'netfs'
         disk.snapshot = 'external'
         disk.driver_name = 'qcow2'
         obj.add_disk(disk)
@@ -2490,7 +2490,7 @@ def test_config_snapshot_with_network_disks(self):
               <name>Demo</name>
               <disks>
                <disk name='vda' snapshot='external' type='network'>
-                <source protocol='glusterfs' name='source-file'>
+                <source protocol='netfs' name='source-file'>
                  <host name='host1' port='12345'/>
                 </source>
                </disk>

nova/tests/unit/virt/libvirt/test_driver.py

@@ -17797,7 +17797,6 @@ def setUp(self):
         self.c = context.get_admin_context()
 
         self.flags(instance_name_template='instance-%s')
-        self.flags(qemu_allowed_storage_drivers=[], group='libvirt')
 
         # creating instance
         self.inst = {}
@@ -17833,17 +17832,17 @@ def setUp(self):
                   </disk>
                   <disk type='network' device='disk'>
                     <driver name='qemu' type='qcow2'/>
-                    <source protocol='gluster' name='vol1/root.img'>
+                    <source protocol='netfs' name='vol1/root.img'>
                       <host name='server1' port='24007'/>
                     </source>
                     <backingStore type='network' index='1'>
                       <driver name='qemu' type='qcow2'/>
-                      <source protocol='gluster' name='vol1/snap.img'>
+                      <source protocol='netfs' name='vol1/snap.img'>
                         <host name='server1' port='24007'/>
                       </source>
                       <backingStore type='network' index='2'>
                         <driver name='qemu' type='qcow2'/>
-                        <source protocol='gluster' name='vol1/snap-b.img'>
+                        <source protocol='netfs' name='vol1/snap-b.img'>
                           <host name='server1' port='24007'/>
                         </source>
                         <backingStore/>
@@ -17867,12 +17866,12 @@ def setUp(self):
                   </disk>
                   <disk type='network' device='disk'>
                     <driver name='qemu' type='qcow2'/>
-                    <source protocol='gluster' name='vol1/snap.img'>
+                    <source protocol='netfs' name='vol1/snap.img'>
                       <host name='server1' port='24007'/>
                     </source>
                     <backingStore type='network' index='1'>
                       <driver name='qemu' type='qcow2'/>
-                      <source protocol='gluster' name='vol1/root.img'>
+                      <source protocol='netfs' name='vol1/root.img'>
                         <host name='server1' port='24007'/>
                       </source>
                       <backingStore/>
@@ -18028,7 +18027,6 @@ def _test_volume_snapshot_create(self, quiesce=True, can_quiesce=True,
     def test_volume_snapshot_create_libgfapi(self):
         """Test snapshot creation with libgfapi network disk."""
         self.flags(instance_name_template = 'instance-%s')
-        self.flags(qemu_allowed_storage_drivers = ['gluster'], group='libvirt')
         self.mox.StubOutWithMock(self.drvr._host, 'get_domain')
         self.mox.StubOutWithMock(self.drvr, '_volume_api')
 
@@ -18041,7 +18039,7 @@ def test_volume_snapshot_create_libgfapi(self):
                     <serial>0e38683e-f0af-418f-a3f1-6b67ea0f919d</serial>
                   </disk>
                   <disk type='block'>
-                    <source protocol='gluster' name='gluster1/volume-1234'>
+                    <source protocol='netfs' name='netfs1/volume-1234'>
                       <host name='127.3.4.5' port='24007'/>
                     </source>
                     <target dev='vdb' bus='virtio' serial='1234'/>

nova/virt/libvirt/driver.py

@@ -156,8 +156,6 @@
     'nfs=nova.virt.libvirt.volume.nfs.LibvirtNFSVolumeDriver',
     'smbfs=nova.virt.libvirt.volume.smbfs.LibvirtSMBFSVolumeDriver',
     'aoe=nova.virt.libvirt.volume.aoe.LibvirtAOEVolumeDriver',
-    'glusterfs='
-        'nova.virt.libvirt.volume.glusterfs.LibvirtGlusterfsVolumeDriver',
     'fibre_channel='
         'nova.virt.libvirt.volume.fibrechannel.'
         'LibvirtFibreChannelVolumeDriver',
@@ -400,11 +398,10 @@ def disk_cachemode(self):
         if self._disk_cachemode is None:
             # We prefer 'none' for consistent performance, host crash
             # safety & migration correctness by avoiding host page cache.
-            # Some filesystems (eg GlusterFS via FUSE) don't support
-            # O_DIRECT though. For those we fallback to 'writethrough'
-            # which gives host crash safety, and is safe for migration
-            # provided the filesystem is cache coherent (cluster filesystems
-            # typically are, but things like NFS are not).
+            # Some filesystems don't support O_DIRECT though. For those we
+            # fallback to 'writethrough' which gives host crash safety, and
+            # is safe for migration provided the filesystem is cache coherent
+            # (cluster filesystems typically are, but things like NFS are not).
             self._disk_cachemode = "none"
             if not self._supports_direct_io(CONF.instances_path):
                 self._disk_cachemode = "writethrough"
@@ -1893,7 +1890,7 @@ def _volume_snapshot_create(self, context, instance, guest,
         device_info.parse_dom(xml_doc)
 
         disks_to_snap = []          # to be snapshotted by libvirt
-        network_disks_to_snap = []  # network disks (netfs, gluster, etc.)
+        network_disks_to_snap = []  # network disks (netfs, etc.)
         disks_to_skip = []          # local disks not snapshotted
 
         for guest_disk in device_info.devices:
@@ -1925,7 +1922,12 @@ def _volume_snapshot_create(self, context, instance, guest,
                 new_file_path = os.path.join(os.path.dirname(current_file),
                                              new_file)
                 disks_to_snap.append((current_file, new_file_path))
-            elif disk_info['source_protocol'] in ('gluster', 'netfs'):
+            # NOTE(mriedem): This used to include a check for gluster in
+            # addition to netfs since they were added together. Support for
+            # gluster was removed in the 16.0.0 Pike release. It is unclear,
+            # however, if other volume drivers rely on the netfs disk source
+            # protocol.
+            elif disk_info['source_protocol'] == 'netfs':
                 network_disks_to_snap.append((disk_info, new_file))
 
         if not disks_to_snap and not network_disks_to_snap: