T7528: only stop service if previously deployed

Author: nvollmar

src/conf_mode/service_monitoring_prometheus.py

@@ -173,11 +173,14 @@ def apply(monitoring):
     # Reload systemd manager configuration
     call('systemctl daemon-reload')
     if not monitoring or 'node_exporter' not in monitoring:
-        call(f'systemctl stop {node_exporter_systemd_service}')
+        if os.path.isfile(node_exporter_service_file):
+            call(f'systemctl stop {node_exporter_systemd_service}')
     if not monitoring or 'frr_exporter' not in monitoring:
-        call(f'systemctl stop {frr_exporter_systemd_service}')
+        if os.path.isfile(frr_exporter_service_file):
+            call(f'systemctl stop {frr_exporter_systemd_service}')
     if not monitoring or 'blackbox_exporter' not in monitoring:
-        call(f'systemctl stop {blackbox_exporter_systemd_service}')
+        if os.path.isfile(blackbox_exporter_service_file):
+            call(f'systemctl stop {blackbox_exporter_systemd_service}')
 
     if not monitoring:
         return