Validate Grafana is present for dashboarder service

Check if MON can resolve a grafana service.
This is currently useful in the transition to K8s,
or in OSM distros with absent Grafana.

Fixes Bug 932

Change-Id: I3b5ebf3d8ee3397f16793cd730e7e1fa5f6676d4
Signed-off-by: lavado <glavado@whitestack.com>
diff --git a/osm_mon/dashboarder/dashboarder.py b/osm_mon/dashboarder/dashboarder.py
index dc21e33..bb2935a 100644
--- a/osm_mon/dashboarder/dashboarder.py
+++ b/osm_mon/dashboarder/dashboarder.py
@@ -22,7 +22,7 @@
 ##
 import logging
 import time
-
+import socket
 import peewee
 
 from osm_mon.dashboarder.service import DashboarderService
@@ -40,6 +40,13 @@
         log.debug('dashboard_forever')
         while True:
             try:
+                socket.gethostbyname("grafana")
+                log.debug("Dashboard backend is running")
+            except socket.error:
+                log.debug("Dashboard backend is not available")
+                time.sleep(int(self.conf.get('dashboarder', 'interval')))
+                continue
+            try:
                 self.create_dashboards()
                 time.sleep(int(self.conf.get('dashboarder', 'interval')))
             except peewee.PeeweeException: