bug fix

docker-compose.yml

@@ -1,12 +1,15 @@
-visualizer:
+version: "3.8"
-  image: dockersamples/visualizer:stable  
+
-  ports:   
+services:
-     - "8001:8080"  
+  visualizer:
-  stop_grace_period: 1m30s 
+    image: dockersamples/visualizer:stable  
-  volumes:    - "/var/run/docker.sock:/var/run/docker.sock"  
+    ports:   
-  deploy:    
+      - "8001:8080"  
-    update_config:     
+    stop_grace_period: 1m30s 
-      failure_action: rollback  
+    volumes:    - "/var/run/docker.sock:/var/run/docker.sock"  
-    placement:
+    deploy:    
-      constraints:      
+      update_config:     
-        - 'node.role == manager'
+        failure_action: rollback  
+      placement:
+        constraints:      
+          - 'node.role == manager'