Load balancer fields and probes

  • Release version: Yokohama
  • Updated January 30, 2025
  • 4 minutes to read
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    Summary of Load balancer fields and probes

    This document details how ServiceNow Discovery collects and stores information about various load balancers using probes and sensors. It covers multiple load balancer types, including Citrix Netscalers, Cisco GSS and CSS, F5 BIG-IP, and generic load balancer components. The data is organized into specific tables within the CMDB, each with fields populated by different discovery probes. It is important to note that this content applies specifically to probe- and sensor-based discovery, not pattern-based discovery used for certain devices like F5 Big-IP.

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    By default, the system assigns the discovered IP address of the load balancer as the CI’s IP, typically the management IP. There are configuration options to override this and use the NIC IP address instead.

    Key Fields and Probes by Load Balancer Type

    • Citrix Netscalers [cmdbcilbnetscaler]: Fields such as Serial Number, Asset Tag, and Model ID are gathered via SNMP probes specific to Netscaler identity.
    • Cisco GSS [cmdbcilbciscogss]: Includes Serial Number, Model ID, IP Address, and Manufacturer, collected using Cisco GSS-specific probes.
    • Cisco CSS [cmdbcilbciscocss]: Captures Serial Number, Model ID, IP Address, and Manufacturer via SNMP Load Balancer Identity probes.
    • F5 BIG-IP [cmdbcilbbigip]: Collects details like Active Modules, Asset Tag, Model ID, Failover Mode, Failover Peer, and Serial Number. Some fields may require form customization to be visible.
    • Generic Load Balancer [cmdbcilb]: Tracks Operational Status and Name using multiple probes including Apache, HAProxy, SNMP F5 BIG-IP, and Netscaler.
    • Load Balancer Application [cmdbcilbappl]: Fields include Configuration File, Name, IP Address, Last Discovery, and Version from probes like Apache, HAProxy, and Nginx.
    • Load Balancer Interface [cmdbcilbinterface]: Contains Status, Load Balancer reference, and Name, populated by several probes. Some fields must be added to the form manually.
    • Load Balancer Pool [cmdbcilbpool]: Includes Load Balancing Method, Load Balancer reference, Last Discovery, and Name, sourced from various probes.
    • Load Balancer Pool Member [cmdbcilbpoolmember]: Holds Fully Qualified Domain Name, IP Address, Load Balancer, Last Discovery, Name, Pool, and Service Port. Certain fields require form customization.
    • Load Balancer Service [cmdbcilbservice]: Tracks Input URL, IP Address, Last Port, Load Balancer, Last Discovery, and Service Port through multiple probes.
    • Load Balancer VLAN [cmdbcilbvlan]: Fields include Load Balancer reference, Name, and Tag collected by various probes.

    Additional Notes

    • Several fields across tables are not visible by default and require form customization to be displayed.
    • Discovery also gathers data on Apache web server load balancing modules via SSH probes, such as modjk and modproxy.
    • For detailed Apache web server discovery data, separate documentation should be consulted.

    Practical Application for ServiceNow Customers

    Understanding these fields and probes helps you verify what load balancer data is collected during Discovery, customize forms to show important but hidden fields, and troubleshoot or enhance your Discovery schedules for load balancers. Knowing which probes populate which fields enables better mapping and validation of your load balancer CIs in the CMDB, ensuring accurate and comprehensive infrastructure data for IT operations and service management.

    Discovery stores load balancer information in several tables.

    The information in this topic pertains to discovery with probes and sensors only. If you are using patterns, such as to discover F5 Big-IP load balancers, see the relevant topic for that type of load balancer.

    Note:
    By default, the system uses the discovered IP address of a load balancer for the CI record. This can be the management IP created for the device that is used in the Discovery schedule. For instructions on how to force Discovery to use the IP address of the load balancer's NIC rather than that of a management IP, see IP address selection properties.
    Table 1. Fields on the Citrix Netscalers [cmdb_ci_lb_netscaler] table
    Field label and name Probes that gather data
    Serial Number [serial_number] SNMP - Netscaler - Identity - Serial
    Asset tag [asset_tag] SNMP - Netscaler - Identity
    Model ID [model_id] SNMP - Netscaler - Identity
    Table 2. Fields on the Cisco GSS [cmdb_ci_lb_cisco_gss] table
    Field label and name Probes that gather data
    Serial Number [serial_number] Cisco GSS - Serial Number
    Model ID [model_id] Cisco GSS - Identity
    IP Address [ip_address] Cisco GSS - Network
    Manufacturer [manufacturer] Cisco GSS - Identity
    Table 3. Fields on the Cisco CSS [cmdb_ci_lb_cisco_css] table
    Field label and name Probes that gather data
    Serial Number [serial_number] SNMP - Load Balancer – Identity
    Model ID [model_id]
    IP Address [ip_address]
    Manufacturer [manufacturer]
    Table 4. Fields on the F5 BIG-IP [cmdb_ci_lb_bigip] table
    Field label and name Probes that gather data
    Active modules [active_modules]* SNMP - F5 BIG-IP - System
    Asset tag [asset_tag]
    Model ID [model_id]
    Failover mode [failover_mode]*
    Failover peer [failover_peer]*
    Serial Number [serial_number] Cisco GSS - Serial Number
    *not visible on the form by default. Customize the form to add this field.
    Table 5. Fields on the Load Balancer [cmdb_ci_lb] table
    Field label and name Probes that gather data
    Operational status [operational_status]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • HAProxy - Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    • SNMP - Load Balancer - Identity
    Name [name]
    Table 6. Fields on the Load Balancer Application [cmdb_ci_lb_appl] table
    Field label and name Probes that gather data
    Configuration file [config_file]* Nginx - Get Configuration
    Name [name]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • HAProxy - Get Configuration
    • Nginx - Get Configuration
    IP Address [ip_address]*
    Most recent discovery [last_discovered]*
    Version [version]
    • Apache - Version
    • HAProxy - Version
    • Nginx - Version
    Table 7. Fields on the Load Balancer Interface [cmdb_ci_lb_interface] table
    Field label and name Probes that gather data
    Status [install_status]*
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • HAProxy - Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    Load Balancer [load_balancer]
    Name [name]
    *not visible on the form by default. Customize the form to add this field.
    Table 8. Fields on the Load Balancer Pool [cmdb_ci_lb_pool] table
    Field label and name Probes that gather data
    Load Balancing Method [load_balance_method]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • HAProxy - Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    Load Balancer [load_balancer]
    Most recent discovery [last_discovered]*
    Name [name]
    *not visible on the form by default. Customize the form to add this field.
    Table 9. Fields for Load Balancer Pool Member [cmdb_ci_lb_pool_member] data
    Field label and name Probes that gather data
    Fully qualified domain name [fqdn]*
    • HAProxy - Get Configuration
    • Nginx - Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    IP Address [ip_address]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • HAProxy - Get Configuration
    • Nginx- Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    Load balancer [load_balancer]
    Most recent discovery [last_discovery]*
    Name [name]
    Pool [pool]*
    Service Port [service_port]
    *not visible on the form by default. Customize the form to add this field.
    Table 10. Fields for Load Balancer Service [cmdb_ci_lb_service] data
    Field label and name Probes that gather data
    Input URL [input_url]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • Nginx - Get Configuration
    IP Address [ip_address]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • Cisco GSS - Identity
    • HAProxy - Get Configuration
    • Nginx - Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    Last port [last_port]* HAProxy - Get Configuration
    Load Balancer [load_balancer]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • Cisco GSS - Identity
    • HAProxy - Get Configuration
    • Nginx - Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    Most recent discovery [last_discovery]*
    Service Port [service_port]*
    *not visible on the form by default. Customize the form to add this field.
    Table 11. Fields for Load Balancer VLAN [cmdb_ci_lb_vlan] data
    Field label and name Probes that gather data
    Load Balancer [load_balancer]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • HAProxy - Get Configuration
    • Nginx - Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    Name [name]
    Tag [tag]
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System

    Apache web server data

    Discovery also collects data on Apache web serer load balancing modules using SSH. See Apache mod_jk and mod_proxy discovery for more information on probes for Apache web server data. For information on the tables, fields, and data sources that discovery populates for Apache web servers, see Apache web server discovery.