libvirt: improve the specification of network disks

Allow zero or more hosts, and make the name optional, since only a
host is needed to use nbd. This allows cinder to fully specify the
location of a sheepdog or rbd volume without depending on extra
configuration files, and lays the groundwork for supporting nbd.

Rename the internal attribute source_host to source_name to reflect
its usage in the libvirt xml, and add source_hosts and source_ports
attributes to store the new information.

Fixes: bug 1077817
blueprint better-libvirt-network-volume-support
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>

Change-Id: I8ac431751692e52ba0786768cea996388962922d

nova/tests/virt/libvirt/test_libvirt_config.py

@@ -434,7 +434,7 @@ def test_config_network(self):
         obj = config.LibvirtConfigGuestDisk()
         obj.source_type = "network"
         obj.source_protocol = "iscsi"
-        obj.source_host = "foo.bar.com"
+        obj.source_name = "foo.bar.com"
         obj.driver_name = "qemu"
         obj.driver_format = "qcow2"
         obj.target_dev = "/dev/hda"
@@ -448,11 +448,56 @@ def test_config_network(self):
               <target bus="ide" dev="/dev/hda"/>
             </disk>""")
 
+    def test_config_network_no_name(self):
+        obj = config.LibvirtConfigGuestDisk()
+        obj.source_type = 'network'
+        obj.source_protocol = 'nbd'
+        obj.source_hosts = ['foo.bar.com']
+        obj.source_ports = [None]
+        obj.driver_name = 'qemu'
+        obj.driver_format = 'raw'
+        obj.target_dev = '/dev/vda'
+        obj.target_bus = 'virtio'
+
+        xml = obj.to_xml()
+        self.assertXmlEqual(xml, """
+            <disk type="network" device="disk">
+              <driver name="qemu" type="raw"/>
+              <source protocol="nbd">
+                <host name="foo.bar.com"/>
+              </source>
+              <target bus="virtio" dev="/dev/vda"/>
+            </disk>""")
+
+    def test_config_network_multihost(self):
+        obj = config.LibvirtConfigGuestDisk()
+        obj.source_type = 'network'
+        obj.source_protocol = 'rbd'
+        obj.source_name = 'pool/image'
+        obj.source_hosts = ['foo.bar.com', '::1', '1.2.3.4']
+        obj.source_ports = [None, '123', '456']
+        obj.driver_name = 'qemu'
+        obj.driver_format = 'raw'
+        obj.target_dev = '/dev/vda'
+        obj.target_bus = 'virtio'
+
+        xml = obj.to_xml()
+        self.assertXmlEqual(xml, """
+            <disk type="network" device="disk">
+              <driver name="qemu" type="raw"/>
+              <source name="pool/image" protocol="rbd">
+                <host name="foo.bar.com"/>
+                <host name="::1" port="123"/>
+                <host name="1.2.3.4" port="456"/>
+              </source>
+              <target bus="virtio" dev="/dev/vda"/>
+            </disk>""")
+
     def test_config_network_auth(self):
         obj = config.LibvirtConfigGuestDisk()
         obj.source_type = "network"
         obj.source_protocol = "rbd"
-        obj.source_host = "pool/image"
+        obj.source_name = "pool/image"
         obj.driver_name = "qemu"
         obj.driver_format = "raw"
         obj.target_dev = "/dev/vda"

nova/tests/virt/libvirt/test_libvirt_volume.py

@@ -218,6 +218,32 @@ def test_libvirt_rbd_driver(self):
         self.assertEqual(tree.find('./source/auth'), None)
         libvirt_driver.disconnect_volume(connection_info, "vde")
 
+    def test_libvirt_rbd_driver_hosts(self):
+        libvirt_driver = volume.LibvirtNetVolumeDriver(self.fake_conn)
+        name = 'volume-00000001'
+        vol = {'id': 1, 'name': name}
+        connection_info = self.rbd_connection(vol)
+        disk_info = {
+            "bus": "virtio",
+            "dev": "vde",
+            "type": "disk",
+            }
+        hosts = ['example.com', '1.2.3.4', '::1']
+        ports = [None, '6790', '6791']
+        connection_info['data']['hosts'] = hosts
+        connection_info['data']['ports'] = ports
+        conf = libvirt_driver.connect_volume(connection_info, disk_info)
+        tree = conf.format_dom()
+        self.assertEqual(tree.get('type'), 'network')
+        self.assertEqual(tree.find('./source').get('protocol'), 'rbd')
+        rbd_name = '%s/%s' % ('rbd', name)
+        self.assertEqual(tree.find('./source').get('name'), rbd_name)
+        self.assertEqual(tree.find('./source/auth'), None)
+        found_hosts = tree.findall('./source/host')
+        self.assertEqual([host.get('name') for host in found_hosts], hosts)
+        self.assertEqual([host.get('port') for host in found_hosts], ports)
+        libvirt_driver.disconnect_volume(connection_info, "vde")
+
     def test_libvirt_rbd_driver_auth_enabled(self):
         libvirt_driver = volume.LibvirtNetVolumeDriver(self.fake_conn)
         name = 'volume-00000001'

nova/virt/libvirt/config.py

@@ -460,7 +460,9 @@ def __init__(self, **kwargs):
         self.driver_cache = None
         self.source_path = None
         self.source_protocol = None
-        self.source_host = None
+        self.source_name = None
+        self.source_hosts = []
+        self.source_ports = []
         self.target_dev = None
         self.target_path = None
         self.target_bus = None
@@ -499,8 +501,16 @@ def format_dom(self):
         elif self.source_type == "mount":
             dev.append(etree.Element("source", dir=self.source_path))
         elif self.source_type == "network":
-            dev.append(etree.Element("source", protocol=self.source_protocol,
-                                      name=self.source_host))
+            source = etree.Element("source", protocol=self.source_protocol)
+            if self.source_name is not None:
+                source.set('name', self.source_name)
+            hosts_info = zip(self.source_hosts, self.source_ports)
+            for name, port in hosts_info:
+                host = etree.Element('host', name=name)
+                if port is not None:
+                    host.set('port', port)
+                source.append(host)
+            dev.append(source)
 
         if self.auth_secret_type is not None:
             auth = etree.Element("auth")

nova/virt/libvirt/volume.py

@@ -131,7 +131,7 @@ def connect_volume(self, connection_info, disk_info):
                                           disk_info)
         conf.source_type = "network"
         conf.source_protocol = "fake"
-        conf.source_host = "fake"
+        conf.source_name = "fake"
         return conf
 
 
@@ -145,10 +145,12 @@ def connect_volume(self, connection_info, disk_info):
         conf = super(LibvirtNetVolumeDriver,
                      self).connect_volume(connection_info,
                                           disk_info)
+        netdisk_properties = connection_info['data']
         conf.source_type = "network"
         conf.source_protocol = connection_info['driver_volume_type']
-        conf.source_host = connection_info['data']['name']
-        netdisk_properties = connection_info['data']
+        conf.source_name = netdisk_properties.get('name')
+        conf.source_hosts = netdisk_properties.get('hosts', [])
+        conf.source_ports = netdisk_properties.get('ports', [])
         auth_enabled = netdisk_properties.get('auth_enabled')
         if (conf.source_protocol == 'rbd' and
             CONF.rbd_secret_uuid):