Fix rbd backend not working for none admin ceph user

The 'rbd_user' option allows nova administrators to override the default user
account used for RBD operations, with one that has potentially lower
privileges.  Not all parts of the Nova code honoured the 'rbd_user' option,
which resulted in failures when attempting to use a lesser privileged user for
RBD. This fix ensures the '--id' and '--config' parameters are passed to the
RBD command line tools in all cases.

Change-Id: Id99aa303791143360ad78074184583048e4878f0
Close-bug: 1255536

nova/tests/virt/libvirt/test_libvirt_utils.py

@@ -53,3 +53,45 @@ blah BLAH: bb
         size = libvirt_utils.logical_volume_size('/dev/foo')
         self.assertEqual(expected_commands, executes)
         self.assertEqual(size, 123456789)
+
+    def test_list_rbd_volumes(self):
+        conf = '/etc/ceph/fake_ceph.conf'
+        pool = 'fake_pool'
+        user = 'user'
+        self.flags(images_rbd_ceph_conf=conf, group='libvirt')
+        self.flags(rbd_user=user, group='libvirt')
+        fn = self.mox.CreateMockAnything()
+        self.mox.StubOutWithMock(libvirt_utils.utils,
+                                 'execute')
+        libvirt_utils.utils.execute('rbd', '-p', pool, 'ls', '--id',
+                                    user,
+                                    '--conf', conf).AndReturn(("Out", "Error"))
+        self.mox.ReplayAll()
+
+        libvirt_utils.list_rbd_volumes(pool)
+
+        self.mox.VerifyAll()
+
+    def test_remove_rbd_volumes(self):
+        conf = '/etc/ceph/fake_ceph.conf'
+        pool = 'fake_pool'
+        user = 'user'
+        names = ['volume1', 'volume2', 'volume3']
+        self.flags(images_rbd_ceph_conf=conf, group='libvirt')
+        self.flags(rbd_user=user, group='libvirt')
+        fn = self.mox.CreateMockAnything()
+        self.mox.StubOutWithMock(libvirt_utils.utils, 'execute')
+        libvirt_utils.utils.execute('rbd', '-p', pool, 'rm', 'volume1',
+                                    '--id', user, '--conf', conf, attempts=3,
+                                    run_as_root=True)
+        libvirt_utils.utils.execute('rbd', '-p', pool, 'rm', 'volume2',
+                                    '--id', user, '--conf', conf, attempts=3,
+                                    run_as_root=True)
+        libvirt_utils.utils.execute('rbd', '-p', pool, 'rm', 'volume3',
+                                    '--id', user, '--conf', conf, attempts=3,
+                                    run_as_root=True)
+        self.mox.ReplayAll()
+
+        libvirt_utils.remove_rbd_volumes(pool, *names)
+
+        self.mox.VerifyAll()

nova/virt/libvirt/imagebackend.py

@@ -508,8 +508,10 @@ class Rbd(Image):
 
     def _ceph_args(self):
         args = []
-        args.extend(['--id', self.rbd_user])
-        args.extend(['--conf', self.ceph_conf])
+        if self.rbd_user:
+            args.extend(['--id', self.rbd_user])
+        if self.ceph_conf:
+            args.extend(['--conf', self.ceph_conf])
         return args
 
     def _get_mon_addrs(self):

nova/virt/libvirt/utils.py

@@ -265,12 +265,27 @@ def import_rbd_image(*args):
     execute('rbd', 'import', *args)
 
 
+def _run_rbd(*args, **kwargs):
+    total = list(args)
+
+    if CONF.libvirt.rbd_user:
+        total.extend(['--id', str(CONF.libvirt.rbd_user)])
+    if CONF.libvirt.images_rbd_ceph_conf:
+        total.extend(['--conf', str(CONF.libvirt.images_rbd_ceph_conf)])
+
+    return utils.execute(*total, **kwargs)
+
+
 def list_rbd_volumes(pool):
     """List volumes names for given ceph pool.
 
     :param pool: ceph pool name
     """
-    out, err = utils.execute('rbd', '-p', pool, 'ls')
+    try:
+        out, err = _run_rbd('rbd', '-p', pool, 'ls')
+    except processutils.ProcessExecutionError:
+        # No problem when no volume in rbd pool
+        return []
 
     return [line.strip() for line in out.splitlines()]
 
@@ -278,9 +293,9 @@ def list_rbd_volumes(pool):
 def remove_rbd_volumes(pool, *names):
     """Remove one or more rbd volume."""
     for name in names:
-        rbd_remove = ('rbd', '-p', pool, 'rm', name)
+        rbd_remove = ['rbd', '-p', pool, 'rm', name]
         try:
-            execute(*rbd_remove, attempts=3, run_as_root=True)
+            _run_rbd(*rbd_remove, attempts=3, run_as_root=True)
         except processutils.ProcessExecutionError:
             LOG.warn(_("rbd remove %(name)s in pool %(pool)s failed"),
                      {'name': name, 'pool': pool})