Grafana Shows Reboot in Uptime Graph Despite No Actual Reboot

Question

I am using Netdata as a data source for Grafana to monitor system uptime through InfluxDB. However, the Grafana graph intermittently shows a drop to zero (as if the system rebooted) at 2024-12-27 09:30:00, even though the system was not actually rebooted at that time.

Upon reviewing my Linux system logs, the machine was actually rebooted at Fri, Dec 27, 12:36, but Grafana does not show uptime data around that time.

This suggests a time mismatch between the actual system uptime and what is displayed in Grafana.

I expected the uptime graph to increase continuously unless an actual reboot occurs. The displayed uptime should match the system's actual uptime without false resets or missing data.

How do we reproduce it?

1. Configure Data Sources:
   • Set up Netdata as a data source in Grafana.
   • Store uptime metrics in InfluxDB.
   • Use the following query to fetch uptime data:

     SELECT max("value") FROM "netdata.system.uptime.uptime" 
     WHERE time >= now() - 6h 
     GROUP BY time(1m) fill(null)
     

   • JSON Configuration for Grafana Uptime Panel:

{
 "type": "graph",
 "title": "Uptime",
 "gridPos": {
   "x": 0,
   "y": 0,
   "w": 12,
   "h": 7
 },
 "id": 1,
 "fieldConfig": {
   "defaults": {
     "custom": {}
   },
   "overrides": []
 },
 "pluginVersion": "7.3.6",
 "datasource": "NetData",
 "targets": [
   {
     "alias": "$3",
     "dsType": "influxdb",
     "groupBy": [
       {
         "params": [
           "$__interval"
         ],
         "type": "time"
       },
       {
         "params": [
           "null"
         ],
         "type": "fill"
       }
     ],
     "measurement": "netdata.system.uptime.uptime",
     "orderByTime": "ASC",
     "policy": "default",
     "refId": "A",
     "resultFormat": "time_series",
     "select": [
       [
         {
           "params": [
             "value"
           ],
           "type": "field"
         },
         {
           "params": [],
           "type": "max"
         }
       ]
     ],
     "tags": []
   }
 ],
 "options": {
   "alertThreshold": true
 },
 "renderer": "flot",
 "yaxes": [
   {
     "decimals": 1,
     "format": "s",
     "label": "",
     "logBase": 10,
     "max": null,
     "min": "1",
     "show": true
   },
   {
     "format": "short",
     "label": null,
     "logBase": 1,
     "max": null,
     "min": null,
     "show": false
   }
 ],
 "xaxis": {
   "buckets": null,
   "mode": "time",
   "name": null,
   "show": true,
   "values": []
 },
 "yaxis": {
   "align": false,
   "alignLevel": null
 },
 "lines": true,
 "fill": 3,
 "linewidth": 2,
 "dashLength": 10,
 "spaceLength": 10,
 "pointradius": 5,
 "legend": {
   "alignAsTable": true,
   "avg": true,
   "current": true,
   "max": true,
   "min": true,
   "rightSide": false,
   "show": true,
   "total": false,
   "values": true
 },
 "nullPointMode": "null",
 "tooltip": {
   "shared": true,
   "sort": 0,
   "value_type": "individual"
 },
 "aliasColors": {},
 "seriesOverrides": [],
 "thresholds": [],
 "timeRegions": [],
 "bars": false,
 "dashes": false,
 "height": "",
 "links": [],
 "percentage": false,
 "points": false,
 "stack": false,
 "steppedLine": false,
 "timeFrom": null,
 "timeShift": null,
 "fillGradient": 0,
 "hiddenSeries": false
}

Request for Help:

1. Could this issue be due to how Netdata reports uptime, or is it related to InfluxDB aggregation?