It is complex and time-consuming to identify and troubleshoot exceptions. Application Real-Time Monitoring Service (ARMS) provides the active diagnostics feature to help you identify exceptions such as long response time based on diagnostic reports.
Step 1: Install the ARMS agent
After you install the ARMS agent, ARMS can conduct all-around monitoring on your applications. Select one of the following methods to install the ARMS agent:
- For information about how to install the ARMS agent for a Java application, see Manually install the ARMS agent for a Java application.
- For information about how to install the ARMS agent for an application in a Container Service for Kubernetes (ACK) cluster, see Install the ARMS agent for Java applications deployed in ACK.
- For information about how to install the ARMS agent for an application in an open source Kubernetes environment, see Install the ARMS agent for an application deployed in an open source Kubernetes environment.
Step 2: View the diagnostic report
The installed ARMS agent collects and shows the metrics of applications such as the total number of requests, average response time, number of errors, number of real-time instances, number of full heap garbage collections (Full GCs), number of slow SQL queries, number of exceptions, and number of slow calls within the selected period of time. ARMS allows you to view the diagnostic report of all metrics for troubleshooting. You can also view the diagnostic report of a single metric on the Application Overview page.
View the diagnostic report of all metrics
- Log on to the ARMS console .
- In the left-side navigation pane, choose . In the top navigation bar, select a region.
On the Applications page, if an application has an exception, the Status column of the application is displayed in red.
- On the Applications page, move the pointer over the row of the application. The An exception is detected. Click to view details message appears. Click the red dot to load the diagnostic report. After the diagnostic
report is loaded, move the pointer over the red dot and click Diagnostic Report to go to the Diagnostic Report page.
You can also click the name of the application on the Applications page to go to the Application Overview page. Move the pointer over the
icon on the right of Application Health Overview. If the An exception is detected. Click to view details message appears, click the icon to load the diagnostic report. After the diagnostic report is loaded, click
the icon again to go to the Diagnostic Report page.
- On the Diagnostic Report page, view the application name, time range for the diagnostics, symptom, error demarcation,
root cause analysis, and detection results of metrics.
Figure 1. Diagnostic report 
View the diagnostic report of a single metric
- On the Applications page, click the name of the application to go to the Application Overview page.
- On the Application Overview page, drag the pointer over the curve of a metric and select a time period. Click
View report selected time to go to the Details page.
- On the Details page, view the detection results of this metric within the selected time range.
What to do next
To prevent passive diagnostics after an exception occurs, you can use the alerting feature of ARMS to create an alert for a specific API or all APIs. This ensures that the O&M team receives a notification immediately after an exception occurs.
For more information about how to create an alert, see Create ARMS alerts.