Alert Analysis

Alert Analysis

Overview

This skill provides a structured approach to analyzing operational alerts in ServiceNow ITOM Event Management. It covers:

• Querying and filtering active alerts by severity and state
• Identifying alert patterns and recurring noise
• Configuring alert grouping and correlation rules
• Building suppression rules to reduce alert fatigue
• Tracing root cause indicators through correlated alerts
• Assessing alert severity against CI business criticality

When to use: When the operations team needs to triage a flood of alerts, identify recurring noise, correlate related alerts, or tune event management rules.

Plugin required: com.snc.event_management

Prerequisites

• Roles: evt_mgmt_admin, evt_mgmt_user, or itil
• Access: Read/write to em_alert, em_event, evt_mgmt_alert_actions tables
• Knowledge: Familiarity with ITOM Event Management concepts, alert lifecycle states, and CI relationships
• Plugins: com.snc.event_management must be activated

Procedure

Step 1: Query Active Alerts by Severity

Retrieve current open alerts to understand the operational landscape.

Using MCP:

Tool: SN-Query-Table
Parameters:
  table_name: em_alert
  query: state!=Closed^ORDERBYDESCseverity
  fields: sys_id,number,description,severity,state,source,node,ci,group_source,acknowledged,sys_created_on
  limit: 50

Using REST API:

GET /api/now/table/em_alert?sysparm_query=state!=Closed^ORDERBYDESCseverity&sysparm_fields=sys_id,number,description,severity,state,source,node,ci,group_source,acknowledged,sys_created_on&sysparm_limit=50

Severity reference values:

Step 2: Identify Alert Patterns and Noise

Analyze alert frequency by source and node to detect noisy alert sources.

Using MCP:

Tool: SN-Execute-Background-Script
Parameters:
  description: Identify top noisy alert sources in the last 24 hours
  script: |
    var ga = new GlideAggregate('em_alert');
    ga.addQuery('sys_created_on', '>=', gs.daysAgo(1));
    ga.addQuery('state', '!=', 'Closed');
    ga.addAggregate('COUNT');
    ga.groupBy('source');
    ga.groupBy('node');
    ga.orderByAggregate('COUNT', false);
    ga.setLimit(20);
    ga.query();

    gs.info('=== TOP NOISY ALERT SOURCES (Last 24h) ===');
    while (ga.next()) {
      var count = ga.getAggregate('COUNT');
      var source = ga.source.toString();
      var node = ga.node.toString();
      gs.info('Source: ' + source + ' | Node: ' + node + ' | Count: ' + count);
    }

Using REST API:

GET /api/now/stats/em_alert?sysparm_query=sys_created_on>=javascript:gs.daysAgo(1)^state!=Closed&sysparm_count=true&sysparm_group_by=source,node&sysparm_orderby=COUNT&sysparm_limit=20

Step 3: Analyze Alert Correlation Groups

Review how alerts are being grouped together to detect related issues.

Using MCP:

Tool: SN-Query-Table
Parameters:
  table_name: em_alert
  query: group_source!=NULL^state=Open
  fields: sys_id,number,description,severity,group_source,ci,node,source
  limit: 30

To find all alerts in a specific correlation group:

Tool: SN-Query-Table
Parameters:
  table_name: em_alert
  query: group_source=[parent_alert_sys_id]
  fields: sys_id,number,description,severity,node,ci,source,sys_created_on

Check alert metric correlations:

Tool: SN-Query-Table
Parameters:
  table_name: em_alert_metric_correlation
  query: alert=[alert_sys_id]
  fields: sys_id,alert,metric_name,ci,correlation_strength,sys_created_on

Step 4: Review and Create Suppression Rules

Examine existing suppression rules and create new ones for identified noise.

List existing alert action rules:

Tool: SN-Query-Table
Parameters:
  table_name: evt_mgmt_alert_actions
  query: active=true
  fields: sys_id,name,description,type,order,active,filter_conditions
  limit: 50

Using REST API to create a suppression rule:

POST /api/now/table/evt_mgmt_alert_actions
Content-Type: application/json

{
  "name": "Suppress disk space warnings on dev servers",
  "type": "Suppress",
  "active": true,
  "order": 100,
  "filter_conditions": "source=Nagios^descriptionLIKEdisk space^nodeLIKEdev-",
  "description": "Suppress low-severity disk space warnings from development servers"
}

Step 5: Assess Impact Through CI Relationships

Cross-reference alerts with CI business criticality and service impact.

Using MCP:

Tool: SN-Execute-Background-Script
Parameters:
  description: Enrich critical alerts with CI business context
  script: |
    var gr = new GlideRecord('em_alert');
    gr.addQuery('state', 'Open');
    gr.addQuery('severity', '<=', 2);  // Critical and Major
    gr.query();

    gs.info('=== CRITICAL ALERT IMPACT ANALYSIS ===');
    while (gr.next()) {
      var alertNum = gr.number.toString();
      var ciId = gr.ci.toString();
      var severity = gr.severity.getDisplayValue();

      if (ciId) {
        var ci = new GlideRecord('cmdb_ci');
        if (ci.get(ciId)) {
          var criticality = ci.business_criticality.getDisplayValue() || 'Not Set';
          var supportGroup = ci.support_group.getDisplayValue() || 'Unassigned';

          // Check service associations
          var svcCount = 0;
          var svcAssoc = new GlideRecord('service_ci_assoc');
          svcAssoc.addQuery('ci_id', ciId);
          svcAssoc.query();
          svcCount = svcAssoc.getRowCount();

          gs.info(alertNum + ' | Severity: ' + severity +
            ' | CI: ' + ci.name + ' | Criticality: ' + criticality +
            ' | Support: ' + supportGroup + ' | Services Affected: ' + svcCount);
        }
      } else {
        gs.info(alertNum + ' | Severity: ' + severity + ' | CI: NOT MAPPED');
      }
    }

Check em_impact for business service impact:

Tool: SN-Query-Table
Parameters:
  table_name: em_impact
  query: alert=[alert_sys_id]
  fields: sys_id,alert,business_service,impact_level,ci

Step 6: Acknowledge and Manage Alert State

Update alert states after analysis is complete.

Acknowledge an alert:

Tool: SN-Update-Record
Parameters:
  table_name: em_alert
  sys_id: [alert_sys_id]
  data:
    acknowledged: true
    work_notes: "Alert reviewed during operational analysis. Root cause traced to [description]. Monitoring."

Close a resolved alert:

Tool: SN-Update-Record
Parameters:
  table_name: em_alert
  sys_id: [alert_sys_id]
  data:
    state: Closed
    close_notes: "Root cause resolved. Disk space freed on node prod-web-03."

Tool Usage

MCP Tools Reference

REST API Reference

Best Practices

• Triage by Severity First: Always address Critical (1) and Major (2) alerts before moving to lower severities
• Map Alerts to CIs: Unmapped alerts lose business context; prioritize CI mapping in event rules
• Review Noise Weekly: Schedule weekly reviews of top alert sources to maintain suppression rules
• Use Correlation Before Suppression: Correlating related alerts preserves signal; suppressing hides it
• Document Suppression Rationale: Always record why a suppression rule was created for future audit
• Validate Severity Alignment: Ensure alert severity matches CI business criticality -- a Warning on a Tier-1 service may warrant escalation

Troubleshooting

Alerts Not Appearing in Console

Cause: Events are not being processed into alerts Solution: Check em_event table for raw events. Verify event rules in evt_mgmt_alert_actions are mapping events to alerts correctly.

Too Many Duplicate Alerts

Cause: Missing or misconfigured alert grouping rules Solution: Review alert correlation rules. Ensure the group_source field logic matches on source, node, and type combinations.

Suppression Rule Not Taking Effect

Cause: Rule order conflict or filter condition mismatch Solution: Check the order field -- lower numbers execute first. Test filter conditions by querying em_alert with the same encoded query.

CI Not Linked to Alert

Cause: Event payload missing ci_identifier or lookup rules not matching Solution: Review the event payload for CI identification fields. Check CI lookup rules in Event Management settings.

Examples

Example 1: Triage a Critical Alert Spike

# 1. Find all Critical alerts from the last hour
Tool: SN-Query-Table
Parameters:
  table_name: em_alert
  query: severity=1^sys_created_on>=javascript:gs.hoursAgo(1)
  fields: sys_id,number,description,source,node,ci,state
  limit: 50

# 2. Group by source to identify if it is a single source flooding
Tool: SN-Execute-Background-Script
Parameters:
  description: Group critical alerts by source
  script: |
    var ga = new GlideAggregate('em_alert');
    ga.addQuery('severity', 1);
    ga.addQuery('sys_created_on', '>=', gs.hoursAgo(1));
    ga.addAggregate('COUNT');
    ga.groupBy('source');
    ga.query();
    while (ga.next()) {
      gs.info('Source: ' + ga.source + ' | Count: ' + ga.getAggregate('COUNT'));
    }

# 3. If single source, consider temporary suppression or investigation

Example 2: Build a Noise Reduction Report

# 1. Aggregate alerts by source, type, and node over the last 7 days
Tool: SN-Execute-Background-Script
Parameters:
  description: Weekly noise report
  script: |
    var ga = new GlideAggregate('em_alert');
    ga.addQuery('sys_created_on', '>=', gs.daysAgo(7));
    ga.addAggregate('COUNT');
    ga.groupBy('source');
    ga.groupBy('description');
    ga.orderByAggregate('COUNT', false);
    ga.setLimit(15);
    ga.query();

    gs.info('=== WEEKLY NOISE REPORT ===');
    gs.info('Top 15 recurring alert types (last 7 days):');
    var rank = 1;
    while (ga.next()) {
      gs.info(rank + '. Source: ' + ga.source +
        ' | Description: ' + ga.description +
        ' | Count: ' + ga.getAggregate('COUNT'));
      rank++;
    }

Example 3: Correlate Alerts for a Single CI

# 1. Find all alerts for a specific CI
Tool: SN-Query-Table
Parameters:
  table_name: em_alert
  query: ci=[ci_sys_id]^state!=Closed^ORDERBYDESCsys_created_on
  fields: sys_id,number,description,severity,state,source,sys_created_on
  limit: 20

# 2. Check metric correlations
Tool: SN-Query-Table
Parameters:
  table_name: em_alert_metric_correlation
  query: ci=[ci_sys_id]
  fields: alert,metric_name,correlation_strength

Related Skills

• itom/alert-investigation - Deep-dive investigation of individual alerts
• itom/service-mapping - Understand service dependencies behind alerts
• itom/health-log-analytics - Anomaly detection and log-based alerting
• itom/observability-integration - Ingest alerts from external monitoring tools
• cmdb/impact-analysis - Assess business impact of alerting CIs

References

• ServiceNow Event Management
• Alert Correlation
• Event Management Best Practices