discovery-patterns

Discovery Patterns for ServiceNow Discovery automatically populates the CMDB by scanning networks and systems. Discovery Architecture Discovery Schedule ↓ MID Server ↓ Probes (collect data) ↓ Sensors (process data) ↓ Identification Rules (match/create CIs) ↓ CMDB Population Key Tables Table Purpose discovery_schedule Discovery schedules discovery_credentials Discovery credentials discovery_range IP ranges to scan cmdb_identification_rule CI identification ecc_agent MID Server records discovery_status Discovery run status Discovery Schedules (ES5) Create Discovery Schedule // Create discovery schedule (ES5 ONLY!) var schedule = new GlideRecord ( "discovery_schedule" ) schedule . initialize ( ) // Basic info schedule . setValue ( "name" , "Data Center Discovery" ) schedule . setValue ( "description" , "Weekly discovery of data center infrastructure" ) // Type schedule . setValue ( "discover" , "IP" ) // IP, CI, Cloud Resources // Schedule schedule . setValue ( "run_type" , "weekly" ) schedule . setValue ( "run_dayofweek" , "sunday" ) schedule . setValue ( "run_time" , "02:00:00" ) // MID Server schedule . setValue ( "mid_server" , getMIDServerSysId ( "DataCenterMID" ) ) // Enable schedule . setValue ( "active" , true ) var scheduleSysId = schedule . insert ( ) // Add IP range addDiscoveryRange ( scheduleSysId , "10.0.0.0" , "10.0.255.255" , "Data Center Network" ) Add Discovery Range // Add IP range to discovery schedule (ES5 ONLY!) function addDiscoveryRange ( scheduleSysId , startIP , endIP , name ) { var range = new GlideRecord ( "discovery_range" ) range . initialize ( ) range . setValue ( "schedule" , scheduleSysId ) range . setValue ( "name" , name ) range . setValue ( "type" , "range" ) range . setValue ( "range_start" , startIP ) range . setValue ( "range_end" , endIP ) range . setValue ( "active" , true ) return range . insert ( ) } // Add CIDR range function addDiscoveryCIDR ( scheduleSysId , cidr , name ) { var range = new GlideRecord ( "discovery_range" ) range . initialize ( ) range . setValue ( "schedule" , scheduleSysId ) range . setValue ( "name" , name ) range . setValue ( "type" , "cidr" ) range . setValue ( "range" , cidr ) // e.g., '10.0.0.0/24' range . setValue ( "active" , true ) return range . insert ( ) } Discovery Credentials (ES5) Create Credentials // Create Windows credential (ES5 ONLY!) var cred = new GlideRecord ( "discovery_credentials" ) cred . initialize ( ) cred . setValue ( "name" , "Windows Domain Admin" ) cred . setValue ( "type" , "windows" ) cred . setValue ( "user_name" , "domain\admin" ) cred . setValue ( "password" , "" ) // Set via secure method cred . setValue ( "active" , true ) // Credential order cred . setValue ( "order" , 100 ) // Assign to credential affinity cred . setValue ( "credential_alias" , credentialAliasSysId ) cred . insert ( ) Credential Affinity // Create credential affinity (map credentials to IP ranges) (ES5 ONLY!) var affinity = new GlideRecord ( "dscy_credentials_affinity" ) affinity . initialize ( ) affinity . setValue ( "credential" , credentialSysId ) affinity . setValue ( "range" , discoveryRangeSysId ) affinity . setValue ( "order" , 100 ) affinity . insert ( ) Custom Probes and Sensors (ES5) Custom Probe // Create custom probe script (ES5 ONLY!) // Probes run on MID Server to collect data // Table: discovery_probes_script var probe = new GlideRecord ( "discovery_probes_script" ) probe . initialize ( ) probe . setValue ( "name" , "Custom Application Version" ) probe . setValue ( "active" , true ) // Probe script (runs on MID Server - ES5 ONLY!) probe . setValue ( "script" , "var output = {};\n" + "\n" + "// Command to run\n" + 'var cmd = "cat /opt/myapp/version.txt";\n' + "\n" + "try {\n" + " var result = Packages.com.service_now.mid.probe.tpcon.OperatingSystemCommand.execute(cmd);\n" + " output.app_version = result.getOutput().trim();\n" + " output.success = true;\n" + "} catch (e) {\n" + " output.success = false;\n" + " output.error = e.message;\n" + "}\n" + "\n" + "output;" , ) probe . insert ( ) Custom Sensor // Create custom sensor (ES5 ONLY!) // Sensors run on ServiceNow instance to process probe results // Table: discovery_sensors_script var sensor = new GlideRecord ( "discovery_sensors_script" ) sensor . initialize ( ) sensor . setValue ( "name" , "Process Custom Application Version" ) sensor . setValue ( "active" , true ) sensor . setValue ( "probe" , probeSysId ) // Sensor script (runs on instance - ES5 ONLY!) sensor . setValue ( "script" , "(function process(result, source) {\n" + " var output = JSON.parse(result.output);\n" + " \n" + " if (!output.success) {\n" + ' gs.warn("Custom app discovery failed: " + output.error);\n' + " return;\n" + " }\n" + " \n" + " // Find or create CI\n" + " var ci = source.getDeviceRecord();\n" + " if (ci) {\n" + " ci.u_custom_app_version = output.app_version;\n" + " ci.update();\n" + ' gs.info("Updated CI with app version: " + output.app_version);\n' + " }\n" + "})(result, source);" , ) sensor . insert ( ) Identification Rules (ES5) CI Identification Rule // Create identification rule (ES5 ONLY!) var rule = new GlideRecord ( "cmdb_identifier" ) rule . initialize ( ) rule . setValue ( "name" , "Server Identification" ) rule . setValue ( "table" , "cmdb_ci_server" ) rule . setValue ( "active" , true ) // Priority (lower = higher priority) rule . setValue ( "order" , 100 ) // Identification entries (criteria) rule . insert ( ) // Add identification criteria var entry = new GlideRecord ( "cmdb_identifier_entry" ) entry . initialize ( ) entry . setValue ( "identifier" , rule . getUniqueValue ( ) ) entry . setValue ( "criterion_attributes" , "serial_number" ) // Match by serial entry . setValue ( "search_type" , "equals" ) entry . setValue ( "active" , true ) entry . insert ( ) Custom Identification Script // Identification script for complex matching (ES5 ONLY!) // Table: cmdb_identifier_script var script = new GlideRecord ( "cmdb_identifier_script" ) script . initialize ( ) script . setValue ( "name" , "Custom Server Match" ) script . setValue ( "table" , "cmdb_ci_server" ) script . setValue ( "active" , true ) script . setValue ( "script" , "(function identify(source) {\n" + ' var serial = source.getValue("serial_number");\n' + ' var hostname = source.getValue("name");\n' + " \n" + " // Try serial match first\n" + ' var gr = new GlideRecord("cmdb_ci_server");\n' + " if (serial) {\n" + ' gr.addQuery("serial_number", serial);\n' + " gr.query();\n" + " if (gr.next()) {\n" + " return gr.getUniqueValue();\n" + " }\n" + " }\n" + " \n" + " // Try hostname + IP match\n" + ' gr = new GlideRecord("cmdb_ci_server");\n' + ' gr.addQuery("name", hostname);\n' + ' gr.addQuery("ip_address", source.getValue("ip_address"));\n' + " gr.query();\n" + " if (gr.next()) {\n" + " return gr.getUniqueValue();\n" + " }\n" + " \n" + " // No match - return null to create new CI\n" + " return null;\n" + "})(source);" , ) script . insert ( ) Discovery Status (ES5) Monitor Discovery Status // Check discovery run status (ES5 ONLY!) function getDiscoveryStatus ( scheduleSysId ) { var status = new GlideRecord ( "discovery_status" ) status . addQuery ( "dscheduler" , scheduleSysId ) status . orderByDesc ( "sys_created_on" ) status . setLimit ( 1 ) status . query ( ) if ( status . next ( ) ) { return { state : status . state . getDisplayValue ( ) , started : status . getValue ( "started" ) , completed : status . getValue ( "completed" ) , devices_found : status . getValue ( "devices_found" ) , devices_completed : status . getValue ( "devices_completed" ) , errors : status . getValue ( "error_count" ) , } } return null } Discovery Device Results // Get discovered devices from a run (ES5 ONLY!) function getDiscoveredDevices ( statusSysId ) { var devices = [ ] var device = new GlideRecord ( "discovery_device_history" ) device . addQuery ( "status" , statusSysId ) device . query ( ) while ( device . next ( ) ) { devices . push ( { ip_address : device . getValue ( "source" ) , ci : device . cmdb_ci . getDisplayValue ( ) , ci_class : device . getValue ( "ci_type" ) , state : device . state . getDisplayValue ( ) , issues : device . getValue ( "issue_count" ) , } ) } return devices } MCP Tool Integration Available Tools Tool Purpose snow_query_table Query discovery tables snow_find_artifact Find discovery configs snow_execute_script_with_output Test discovery scripts snow_cmdb_search Search discovered CIs Example Workflow // 1. Query active schedules await snow_query_table ( { table : "discovery_schedule" , query : "active=true" , fields : "name,discover,run_type,mid_server" , } ) // 2. Check recent discovery status await snow_execute_script_with_output ( { script : var status = getDiscoveryStatus('schedule_sys_id'); gs.info(JSON.stringify(status)); , } ) // 3. Find discovery errors await snow_query_table ( { table : "discovery_log" , query : "level=error^sys_created_on>=javascript:gs.daysAgo(1)" , fields : "message,source,sys_created_on" , } ) Best Practices Credential Security - Use credential vault Schedule Off-Peak - Minimize network impact Range Management - Organize by network segment MID Server - Proper placement and sizing Identification - Clear matching criteria Reconciliation - Regular CMDB validation Monitoring - Track discovery health ES5 Only - No modern JavaScript syntax