Set correct nginx_up query and instance variable expression

Signed-off-by: EdgarasG <edgaras.giedre@hostinger.com>

Author: edgarasg

grafana/dashboard.json

@@ -136,7 +136,7 @@
             "tableColumn": "",
             "targets": [
                 {
-                    "expr": "nginx_up{instance=\"$instance\"}",
+                    "expr": "nginx_up{instance=~\"$instance\"}",
                     "format": "time_series",
                     "instant": false,
                     "intervalFactor": 1,
@@ -486,14 +486,14 @@
                 "allValue": null,
                 "current": {},
                 "datasource": "${DS_PROMETHEUS}",
-                "definition": "label_values(instance)",
+                "definition": "label_values(nginx_up, instance)",
                 "hide": 0,
                 "includeAll": true,
                 "label": "",
                 "multi": true,
                 "name": "instance",
                 "options": [],
-                "query": "label_values(instance)",
+                "query": "label_values(nginx_up, instance)",
                 "refresh": 1,
                 "regex": "",
                 "skipUrlSync": false,
@@ -539,4 +539,4 @@
     "title": "NGINX",
     "uid": "MsjffzSZz",
     "version": 1
-}
+}