rbd: send ceph monitor addresses with connection info

Previously we relied on a ceph configuration file on the compute host
for this information. Sending the info directly from cinder makes more
complex setups with multiple ceph clusters talking to the same compute
hosts possible.

Refresh the monitor addresses for each initialize_connection() call,
since monitors may be added or removed while cinder-volume is
running.

Fixes: bug 1077817
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>

Change-Id: I34a1fa16ce1f4524ba25832faf3129303e755100

cinder/tests/test_rbd.py

@@ -35,6 +35,34 @@
 LOG = logging.getLogger(__name__)
 
 
+CEPH_MON_DUMP = """dumped monmap epoch 1
+{ "epoch": 1,
+  "fsid": "33630410-6d93-4d66-8e42-3b953cf194aa",
+  "modified": "2013-05-22 17:44:56.343618",
+  "created": "2013-05-22 17:44:56.343618",
+  "mons": [
+        { "rank": 0,
+          "name": "a",
+          "addr": "[::1]:6789\/0"},
+        { "rank": 1,
+          "name": "b",
+          "addr": "[::1]:6790\/0"},
+        { "rank": 2,
+          "name": "c",
+          "addr": "[::1]:6791\/0"},
+        { "rank": 3,
+          "name": "d",
+          "addr": "127.0.0.1:6792\/0"},
+        { "rank": 4,
+          "name": "e",
+          "addr": "example.com:6791\/0"}],
+  "quorum": [
+        0,
+        1,
+        2]}
+"""
+
+
 class FakeImageService:
     def download(self, context, image_id, path):
         pass
@@ -190,6 +218,34 @@ def fake_safe_get(*args):
         actual = self.driver.get_volume_stats(True)
         self.assertDictMatch(expected, actual)
 
+    def test_get_mon_addrs(self):
+        self.stubs.Set(self.driver, '_execute',
+                       lambda *a: (CEPH_MON_DUMP, ''))
+        hosts = ['::1', '::1', '::1', '127.0.0.1', 'example.com']
+        ports = ['6789', '6790', '6791', '6792', '6791']
+        self.assertEqual((hosts, ports), self.driver._get_mon_addrs())
+
+    def test_initialize_connection(self):
+        name = 'volume-00000001'
+        hosts = ['::1', '::1', '::1', '127.0.0.1', 'example.com']
+        ports = ['6789', '6790', '6791', '6792', '6791']
+        self.stubs.Set(self.driver, '_get_mon_addrs', lambda: (hosts, ports))
+        expected = {
+            'driver_volume_type': 'rbd',
+            'data': {
+                'name': '%s/%s' % (self.configuration.rbd_pool,
+                                   name),
+                'hosts': hosts,
+                'ports': ports,
+                'auth_enabled': False,
+                'auth_username': None,
+                'secret_type': 'ceph',
+                'secret_uuid': None,
+                }
+        }
+        actual = self.driver.initialize_connection(dict(name=name), None)
+        self.assertDictMatch(expected, actual)
+
 
 class ManagedRBDTestCase(DriverTestCase):
     driver_name = "cinder.volume.drivers.rbd.RBDDriver"

cinder/volume/drivers/rbd.py

@@ -65,6 +65,23 @@ def check_for_setup_error(self):
                                  self.configuration.rbd_pool)
             raise exception.VolumeBackendAPIException(data=exception_message)
 
+    def _get_mon_addrs(self):
+        args = ['ceph', 'mon', 'dump', '--format=json']
+        out, _ = self._execute(*args)
+        lines = out.split('\n')
+        if lines[0].startswith('dumped monmap epoch'):
+            lines = lines[1:]
+        monmap = json.loads('\n'.join(lines))
+        addrs = [mon['addr'] for mon in monmap['mons']]
+        hosts = []
+        ports = []
+        for addr in addrs:
+            host_port = addr[:addr.rindex('/')]
+            host, port = host_port.rsplit(':', 1)
+            hosts.append(host.strip('[]'))
+            ports.append(port)
+        return hosts, ports
+
     def _update_volume_stats(self):
         stats = {'vendor_name': 'Open Source',
                  'driver_version': VERSION,
@@ -199,11 +216,14 @@ def remove_export(self, context, volume):
         pass
 
     def initialize_connection(self, volume, connector):
+        hosts, ports = self._get_mon_addrs()
         return {
             'driver_volume_type': 'rbd',
             'data': {
                 'name': '%s/%s' % (self.configuration.rbd_pool,
                                    volume['name']),
+                'hosts': hosts,
+                'ports': ports,
                 'auth_enabled': (self.configuration.rbd_secret_uuid
                                  is not None),
                 'auth_username': self.configuration.rbd_user,