What is the self-health monitoring feature?

Enabling the OOTB available self-health feature can help detect and troubleshoot Event Management health issues. Some examples below may help you further understand this better before we dig into this a little more -

Example 1 : A classic example of what a self-monitoring alert would look like. As you can see, this is an alert created when the system observed an issue with MID Server availability or when resource thresholds are detected in the ServiceNow Environment. In the example below, you can see the MID server was not able to connect with the service bus and hence there were two events generated against the alert.

Also, you can see the default values are populated like CI which is the MID server, metric name along with a description of what the issue is in depth.

Example 2 : An auto-created alert that shows that there is a delay in the impact calculator job, as you can see it already has a configuration item pre-selected, type as self-monitoring, and source as EMSelfMonitoring.

On the ‘ServiceNow Event Management’ Application service you can see all the CIs which are related to the event management module.

Source: ServiceNow Documentation

How to enable/disable this feature ?

This is available OOTB as a feature, it just needs to be enabled/disabled via a property -

System Property - evt_mgmt.self_health_active

The property can have one of these values -

Enabled - The ServiceNow Event Management application service is created and set to monitor self-health. Events are received and alerts are generated. The first time that the self-health monitoring property is enabled, it automatically creates the ServiceNow Event Management application service.

Alerts Only - The ServiceNow Event Management application service and the CIs related to it are not created. Alerts are created but are not bound to a CI.

Disabled - The ServiceNow Event Management application service is not operational. Events are not received, and alerts are not generated.

What are the OOTB self-health monitors and what if I want to create a custom monitor definition?

All the definitions that determine which Event Management components are being monitored are stored in the ‘em_monitor_conf’ table. Below are the listed jobs available out of the box -