diff --git a/.zuul.yaml b/.zuul.yaml
index 8a736ef689..8c26061a2b 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -214,9 +214,26 @@
         - devstack-plugin-ceph-tempest:
             voting: false
             irrelevant-files: *dsvm-irrelevant-files
+        # TODO(mriedem): We need to move this job definition in-tree from
+        # openstack-zuul-jobs.
         - legacy-grenade-dsvm-neutron-multinode-live-migration:
             voting: false
-            irrelevant-files: *dsvm-irrelevant-files
+            irrelevant-files:
+              # We define our own irrelevant-files because we need to run
+              # this if there are changes to nova/tests/live_migration/.
+              - ^api-.*$
+              - ^(test-|)requirements.txt$
+              - ^.*\.rst$
+              - ^.git.*$
+              - ^doc/.*$
+              - ^nova/hacking/.*$
+              - ^nova/locale/.*$
+              - ^(?!nova/tests/live_migration/).*$
+              - ^releasenotes/.*$
+              - ^setup.cfg$
+              - ^tests-py3.txt$
+              - ^tools/.*$
+              - ^tox.ini$
         - neutron-grenade:
             irrelevant-files: *dsvm-irrelevant-files
         - neutron-grenade-multinode:
diff --git a/nova/tests/live_migration/hooks/run_tests.sh b/nova/tests/live_migration/hooks/run_tests.sh
index 72e0bab83d..71afed4629 100755
--- a/nova/tests/live_migration/hooks/run_tests.sh
+++ b/nova/tests/live_migration/hooks/run_tests.sh
@@ -48,16 +48,6 @@ prepare_ceph
 GLANCE_API_CONF=${GLANCE_API_CONF:-/etc/glance/glance-api.conf}
 configure_and_start_glance
 
-# Deal with grenade craziness...
-if [ "$GRENADE_OLD_BRANCH" ]; then
-    # NOTE(mriedem): Grenade runs in singleconductor mode, so it won't use
-    # /etc/nova/nova-cpu.conf so we have to overwrite NOVA_CPU_CONF which is
-    # read in configure_and_start_nova.
-    if ! is_service_enabled n-super-cond; then
-        NOVA_CPU_CONF=$NOVA_CONF
-    fi
-fi
-
 configure_and_start_nova
 run_tempest "Ceph nova&glance test" "^.*test_live_migration(?!.*(test_volume_backed_live_migration))"