diff --git a/nova_solverscheduler/scheduler/solvers/constraints/server_group_affinity_constraint.py b/nova_solverscheduler/scheduler/solvers/constraints/server_group_affinity_constraint.py
index fb97eb2..f99f94a 100644
--- a/nova_solverscheduler/scheduler/solvers/constraints/server_group_affinity_constraint.py
+++ b/nova_solverscheduler/scheduler/solvers/constraints/server_group_affinity_constraint.py
@@ -13,8 +13,12 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from oslo_log import log as logging
+
 from nova_solverscheduler.scheduler.solvers import constraints
 
+LOG = logging.getLogger(__name__)
+
 
 class ServerGroupAffinityConstraint(constraints.BaseLinearConstraint):
     """Force to select hosts which host given server group."""
@@ -36,6 +40,9 @@ class ServerGroupAffinityConstraint(constraints.BaseLinearConstraint):
 
         group_hosts = filter_properties.get('group_hosts')
 
+        LOG.debug('Group hosts: %(hosts)s.',
+                  {'hosts': ', '.join(group_hosts)})
+
         if not group_hosts:
             constraint_matrix = [
                     ([False for j in xrange(num_instances - 1)] + [True])
@@ -45,6 +52,9 @@ class ServerGroupAffinityConstraint(constraints.BaseLinearConstraint):
                 if hosts[i].host not in group_hosts:
                     constraint_matrix[i] = [False for
                                             j in xrange(num_instances)]
+                else:
+                    LOG.debug('%(host)s is in group hosts.',
+                              {'host': hosts[i].host})
 
         return constraint_matrix
 
@@ -70,9 +80,14 @@ class ServerGroupAntiAffinityConstraint(constraints.BaseLinearConstraint):
 
         group_hosts = filter_properties.get('group_hosts')
 
+        LOG.debug('Group hosts: %(hosts)s.',
+                  {'hosts': ', '.join(group_hosts)})
+
         for i in xrange(num_hosts):
             if hosts[i].host in group_hosts:
                 constraint_matrix[i] = [False for j in xrange(num_instances)]
+                LOG.debug('%(host)s is in group hosts.',
+                          {'host': hosts[i].host})
             else:
                 constraint_matrix[i] = ([True] + [False for
                                         j in xrange(num_instances - 1)])