Add cold migrate and resize to nova-grenade-multinode

Changes in [1] could potentially break a mixed-compute-version
environment as we don't have grenade coverage for cold migrate and
resize. This adds that coverage to the nova-grenade-multinode
job.

[1]https://review.opendev.org/#/c/655721/10

Change-Id: I81372d610ddf8abb473621deb6e7cb68eb000fee

.zuul.yaml

@@ -251,8 +251,9 @@
     parent: nova-dsvm-multinode-base
     description: |
       Multi-node grenade job which runs gate/live_migration/hooks tests.
-      In other words, this tests live migration with mixed-version compute
-      services which is important for things like rolling upgrade support.
+      In other words, this tests live and cold migration and resize with
+      mixed-version compute services which is important for things like
+      rolling upgrade support.
       The former names for this job were "nova-grenade-live-migration" and
       "legacy-grenade-dsvm-neutron-multinode-live-migration".
     run: playbooks/legacy/nova-grenade-multinode/run.yaml

gate/live_migration/hooks/run_tests.sh

@@ -43,7 +43,16 @@ echo '2. NFS testing is skipped due to setup failures with Ubuntu 16.04'
 #run_tempest  "NFS shared storage test" "live_migration"
 #nfs_teardown
 
-echo '3. test with Ceph for root + ephemeral disks'
+# The nova-grenade-multinode job also runs resize and cold migration tests
+# so we check for a grenade-only variable.
+if [[ -n "$GRENADE_NEW_BRANCH" ]]; then
+    echo '3. test cold migration and resize'
+    run_tempest "cold migration and resize test" "test_resize_server|test_cold_migration|test_revert_cold_migration"
+else
+    echo '3. cold migration and resize is skipped for non-grenade jobs'
+fi
+
+echo '4. test with Ceph for root + ephemeral disks'
 # Discover and set variables for the OS version so the devstack-plugin-ceph
 # scripts can find the correct repository to install the ceph packages.
 GetOSVersion
@@ -55,7 +64,7 @@ configure_and_start_nova
 run_tempest "Ceph nova&glance test" "^.*test_live_migration(?!.*(test_volume_backed_live_migration))"
 
 set +e
-#echo '4. test with Ceph for volumes and root + ephemeral disk'
+#echo '5. test with Ceph for volumes and root + ephemeral disk'
 
 #configure_and_start_cinder
 #run_tempest "Ceph nova&glance&cinder test" "live_migration"