Add volume multi attach support

This patch includes the Cinder changes needed
to support volume multiple attaches.  Nova and
python-cinderclient also need patches associated
to provide support for multiple attachments.

This adds the multiattach flag to volumes.  When a
volume is created, a multiattach flag can be set,
which allows a volume to be attached to more than
one Nova instance or host.  If the multiattach flag is
not set on a volume, it cannot be attached to more
than one Nova instance or host

Each volume attachment is tracked in a
new volume_attachment table.  The attachment id is
the unique identifier for each attachment to an
instance or host.

When a volume is to be detached the attachment
uuid must be passed in to the detach call in
order to determine which attachment should be
removed.  Since a volume can be attached to an
instance and a host, the attachment id is used
as the attachment identifier.

Nova:
https://review.openstack.org/#/c/153033/
https://review.openstack.org/#/c/153038/

python-cinderclient:
https://review.openstack.org/#/c/85856/

Change-Id: I950fa00ed5a30e7758245d5b0557f6df42dc58a3
Implements: blueprint multi-attach-volume
APIImpact

cinder/api/contrib/admin_actions.py

@@ -185,7 +185,10 @@ def _force_detach(self, req, id, body):
             raise exc.HTTPNotFound()
         self.volume_api.terminate_connection(context, volume,
                                              {}, force=True)
-        self.volume_api.detach(context, volume)
+
+        attachment_id = body['os-force_detach'].get('attachment_id', None)
+
+        self.volume_api.detach(context, volume, attachment_id)
         return webob.Response(status_int=202)
 
     @wsgi.action('os-migrate_volume')

cinder/api/contrib/volume_actions.py

@@ -127,7 +127,11 @@ def _detach(self, req, id, body):
         except exception.VolumeNotFound as error:
             raise webob.exc.HTTPNotFound(explanation=error.msg)
 
-        self.volume_api.detach(context, volume)
+        attachment_id = None
+        if body['os-detach']:
+            attachment_id = body['os-detach'].get('attachment_id', None)
+
+        self.volume_api.detach(context, volume, attachment_id)
         return webob.Response(status_int=202)
 
     @wsgi.action('os-reserve')

cinder/api/v1/volumes.py

@@ -48,18 +48,18 @@ def _translate_attachment_detail_view(_context, vol):
 
 def _translate_attachment_summary_view(_context, vol):
     """Maps keys for attachment summary view."""
-    d = {}
-
-    volume_id = vol['id']
-
-    # NOTE(justinsb): We use the volume id as the id of the attachment object
-    d['id'] = volume_id
-
-    d['volume_id'] = volume_id
-    d['server_id'] = vol['instance_uuid']
-    d['host_name'] = vol['attached_host']
-    if vol.get('mountpoint'):
-        d['device'] = vol['mountpoint']
+    d = []
+    attachments = vol.get('volume_attachment', [])
+    for attachment in attachments:
+        if attachment.get('attach_status') == 'attached':
+            a = {'id': attachment.get('volume_id'),
+                 'attachment_id': attachment.get('id'),
+                 'volume_id': attachment.get('volume_id'),
+                 'server_id': attachment.get('instance_uuid'),
+                 'host_name': attachment.get('attached_host'),
+                 'device': attachment.get('mountpoint'),
+                 }
+            d.append(a)
 
     return d
 
@@ -91,10 +91,14 @@ def _translate_volume_summary_view(context, vol, image_id=None):
     else:
         d['bootable'] = 'false'
 
+    if vol['multiattach']:
+        d['multiattach'] = 'true'
+    else:
+        d['multiattach'] = 'false'
+
     d['attachments'] = []
     if vol['attach_status'] == 'attached':
-        attachment = _translate_attachment_detail_view(context, vol)
-        d['attachments'].append(attachment)
+        d['attachments'] = _translate_attachment_detail_view(context, vol)
 
     d['display_name'] = vol['display_name']
     d['display_description'] = vol['display_description']
@@ -146,6 +150,7 @@ def make_volume(elem):
     elem.set('volume_type')
     elem.set('snapshot_id')
     elem.set('source_volid')
+    elem.set('multiattach')
 
     attachments = xmlutil.SubTemplateElement(elem, 'attachments')
     attachment = xmlutil.SubTemplateElement(attachments, 'attachment',
@@ -373,6 +378,8 @@ def create(self, req, body):
             size = kwargs['source_volume']['size']
 
         LOG.info(_LI("Create volume of %s GB"), size, context=context)
+        multiattach = volume.get('multiattach', False)
+        kwargs['multiattach'] = multiattach
 
         image_href = None
         image_uuid = None

cinder/api/v2/views/volumes.py

@@ -70,7 +70,8 @@ def detail(self, request, volume):
                 'bootable': str(volume.get('bootable')).lower(),
                 'encrypted': self._is_volume_encrypted(volume),
                 'replication_status': volume.get('replication_status'),
-                'consistencygroup_id': volume.get('consistencygroup_id')
+                'consistencygroup_id': volume.get('consistencygroup_id'),
+                'multiattach': volume.get('multiattach')
             }
         }
 
@@ -83,19 +84,17 @@ def _get_attachments(self, volume):
         attachments = []
 
         if volume['attach_status'] == 'attached':
-            d = {}
-            volume_id = volume['id']
-
-            # note(justinsb): we use the volume id as the id of the attachments
-            # object
-            d['id'] = volume_id
-
-            d['volume_id'] = volume_id
-            d['server_id'] = volume['instance_uuid']
-            d['host_name'] = volume['attached_host']
-            if volume.get('mountpoint'):
-                d['device'] = volume['mountpoint']
-            attachments.append(d)
+            attaches = volume.get('volume_attachment', [])
+            for attachment in attaches:
+                if attachment.get('attach_status') == 'attached':
+                    a = {'id': attachment.get('volume_id'),
+                         'attachment_id': attachment.get('id'),
+                         'volume_id': attachment.get('volume_id'),
+                         'server_id': attachment.get('instance_uuid'),
+                         'host_name': attachment.get('attached_host'),
+                         'device': attachment.get('mountpoint'),
+                         }
+                    attachments.append(a)
 
         return attachments
 

cinder/api/v2/volumes.py

@@ -44,6 +44,7 @@
 
 def make_attachment(elem):
     elem.set('id')
+    elem.set('attachment_id')
     elem.set('server_id')
     elem.set('host_name')
     elem.set('volume_id')
@@ -63,6 +64,7 @@ def make_volume(elem):
     elem.set('snapshot_id')
     elem.set('source_volid')
     elem.set('consistencygroup_id')
+    elem.set('multiattach')
 
     attachments = xmlutil.SubTemplateElement(elem, 'attachments')
     attachment = xmlutil.SubTemplateElement(attachments, 'attachment',
@@ -412,6 +414,8 @@ def create(self, req, body):
 
         kwargs['availability_zone'] = volume.get('availability_zone', None)
         kwargs['scheduler_hints'] = volume.get('scheduler_hints', None)
+        multiattach = volume.get('multiattach', False)
+        kwargs['multiattach'] = multiattach
 
         new_volume = self.volume_api.create(context,
                                             size,

cinder/backup/manager.py

@@ -197,18 +197,28 @@ def init_host(self):
         for volume in volumes:
             volume_host = volume_utils.extract_host(volume['host'], 'backend')
             backend = self._get_volume_backend(host=volume_host)
-            if volume['status'] == 'backing-up':
-                LOG.info(_LI('Resetting volume %s to available '
-                             '(was backing-up).') % volume['id'])
-                mgr = self._get_manager(backend)
-                mgr.detach_volume(ctxt, volume['id'])
-            if volume['status'] == 'restoring-backup':
-                LOG.info(_LI('Resetting volume %s to error_restoring '
-                             '(was restoring-backup).') % volume['id'])
-                mgr = self._get_manager(backend)
-                mgr.detach_volume(ctxt, volume['id'])
-                self.db.volume_update(ctxt, volume['id'],
-                                      {'status': 'error_restoring'})
+            attachments = volume['volume_attachment']
+            if attachments:
+                if volume['status'] == 'backing-up':
+                    LOG.info(_LI('Resetting volume %s to available '
+                                 '(was backing-up).'), volume['id'])
+                    mgr = self._get_manager(backend)
+                    for attachment in attachments:
+                        if (attachment['attached_host'] == self.host and
+                           attachment['instance_uuid'] is None):
+                            mgr.detach_volume(ctxt, volume['id'],
+                                              attachment['id'])
+                if volume['status'] == 'restoring-backup':
+                    LOG.info(_LI('setting volume %s to error_restoring '
+                                 '(was restoring-backup).'), volume['id'])
+                    mgr = self._get_manager(backend)
+                    for attachment in attachments:
+                        if (attachment['attached_host'] == self.host and
+                           attachment['instance_uuid'] is None):
+                            mgr.detach_volume(ctxt, volume['id'],
+                                              attachment['id'])
+                    self.db.volume_update(ctxt, volume['id'],
+                                          {'status': 'error_restoring'})
 
         # TODO(smulcahy) implement full resume of backup and restore
         # operations on restart (rather than simply resetting)

cinder/db/api.py

@@ -136,10 +136,16 @@ def iscsi_target_create_safe(context, values):
 ###############
 
 
-def volume_attached(context, volume_id, instance_id, host_name, mountpoint):
+def volume_attach(context, values):
+    """Attach a volume."""
+    return IMPL.volume_attach(context, values)
+
+
+def volume_attached(context, volume_id, instance_id, host_name, mountpoint,
+                    attach_mode='rw'):
     """Ensure that a volume is set as attached."""
     return IMPL.volume_attached(context, volume_id, instance_id, host_name,
-                                mountpoint)
+                                mountpoint, attach_mode)
 
 
 def volume_create(context, values):
@@ -169,9 +175,9 @@ def volume_destroy(context, volume_id):
     return IMPL.volume_destroy(context, volume_id)
 
 
-def volume_detached(context, volume_id):
+def volume_detached(context, volume_id, attachment_id):
     """Ensure that a volume is set as detached."""
-    return IMPL.volume_detached(context, volume_id)
+    return IMPL.volume_detached(context, volume_id, attachment_id)
 
 
 def volume_get(context, volume_id):
@@ -219,6 +225,27 @@ def volume_update(context, volume_id, values):
     return IMPL.volume_update(context, volume_id, values)
 
 
+def volume_attachment_update(context, attachment_id, values):
+    return IMPL.volume_attachment_update(context, attachment_id, values)
+
+
+def volume_attachment_get(context, attachment_id, session=None):
+    return IMPL.volume_attachment_get(context, attachment_id, session)
+
+
+def volume_attachment_get_used_by_volume_id(context, volume_id):
+    return IMPL.volume_attachment_get_used_by_volume_id(context, volume_id)
+
+
+def volume_attachment_get_by_host(context, volume_id, host):
+    return IMPL.volume_attachment_get_by_host(context, volume_id, host)
+
+
+def volume_attachment_get_by_instance_uuid(context, volume_id, instance_uuid):
+    return IMPL.volume_attachment_get_by_instance_uuid(context, volume_id,
+                                                       instance_uuid)
+
+
 ####################