ovn: enable northd liveness probe

Closes-Bug: ATMOSPHERE-638
Change-Id: I1feba0cd69d8a956d660a4b5adf5ab042d46ae01
diff --git a/roles/ovn/vars/main.yml b/roles/ovn/vars/main.yml
index 994894f..b879919 100644
--- a/roles/ovn/vars/main.yml
+++ b/roles/ovn/vars/main.yml
@@ -34,6 +34,15 @@
     ovn_ovsdb_sb:
       size: 20Gi
   pod:
+    probes:
+      ovn_northd:
+        northd:
+          liveness:
+            enabled: true
+            params:
+              initialDelaySeconds: 30
+              timeoutSeconds: 30
+              periodSeconds: 60
     replicas:
       ovn_ovsdb_nb: 3
       ovn_ovsdb_sb: 3