Merge pull request #2855 from rina23q/docs/fix-timestamp-format-in-se…

…rvice-monitoring

Update doc: Troubleshooting > Monitoring Service Health

docs/src/operate/troubleshooting/monitoring-service-health.md

@@ -28,16 +28,16 @@ If the response is not received then most likely the service is down, or not res
 For example, `tedge-mapper-c8y` publishes a message on topic `te/device/main/service/tedge-mapper-c8y/status/health` when it starts:
 
 ```json
-{ "pid": 290854, "status": "up", "time": "2023-04-02T21:37:12.345678901Z" }
+{ "pid": 290854, "status": "up", "time": 1714676361.3610663 }
 ```
 
 <!-- TODO: this should be in a reference about health status messages -->
 
-| Property | Description |
-|----------|----------------------------------------------------|
-| `pid` | Process ID of the service |
-| `status` | Service status. Possible values are `up` or `down` |
-| `time` | Timestamp in RFC3339 format  |
+| Property | Description  |
+|----------|------------------------------------------------------------------------------------------------------------------|
+| `pid` | Process ID of the service  |
+| `status` | Service status. Possible values are `up` or `down`  |
+| `time` | Timestamp in either Unix or RFC-3339 format. Configurable by the tedge config setting `service.timestamp_format` |
 
 If the tedge service gets stopped, crashed, or killed, then a `down` message will be published on health status topic
 and this will be retained until the service is restarted.
@@ -52,7 +52,7 @@ tedge mqtt sub 'te/+/+/+/+/status/health'
 INFO: Connected
 [te/device/main/service/mosquitto-c8y-bridge/status/health] 1
 [te/device/main/service/tedge-mapper-c8y/status/health] {"pid":51367,"status":"down"}
-[te/device/main/service/tedge-agent/status/health] {"pid":13280,"status":"up","time":"2023-02-02T09:37:47+00:00"}
+[te/device/main/service/tedge-agent/status/health] {"pid":13280,"status":"up","time":1714676361.3610663}
 ```
 ## Supported MQTT health endpoint topics